TITLE EFFECT PREHARVEST TREATMENT OF CALCIUM CHLORIDE ON POST HARVEST BEHAVIOUR OF MANGO FRUITS
LOCATION OF RESEARCH kanchanpur, Nepal
DURATION OF RESEARCH 8 months EIGHT MONTHS(APRIL 2105 – NOVEMBER 2016)
TYPE OF PROJECT Research
PROJECT STATUS: NEW
SECTOR: post harvest horticulture
RESEARCHER: Hari Paneru
CONTACT NO. 9848513078
EXPECTED COST OF RESEARCH: NRS. 1,17,000/
Mango (Mangifera indica L.) is regarded as the King of fruits from tropical areas of the world. Besides its fresh consumption, it is also used to make the processed products like candy, leather, relishes, pickles, beverages and many more. Among the several varieties of this fruit, Dashahara, Malda, Totapuri, Kalkatiya, Bijuri, Safeda, Alfanso are some of the most demanded varieties in the market.
India is the largest Mango producing country in the world accounting for the production of 19 million
Mt mangos in the year 2008. It is grown over an area of 1.23 million hectares producing 10.99 million MT, which comes be around 52% of the total world production of mangoes. In India, Uttar Pradesh has the largest area of 0.27 million hectares under mango whereas Andhra Pradesh has the highest productivity of 12 MT per hectare. The other states producing mango in India are Andhra Pradesh (3.07 million MT), U.P. (2.39 million MT), Bihar (1.79 million MT) and Karnataka (0.92 million MT). The other major mango producing countries are China, Mexico, Thailand, Indonesia, Pakistan, Nigeria, Philippines, Brazil, Egypt and Haiti.
In Nepal, as per the agriculture statistics, the total area covered by Mango in the year 2007/08 was 14781 Ha from which 110736 MT of the mango was produced. The 10 major districts of mango production are Siraha, Sarlahi, Mahottari, Sunsari, Dhanusha, Saptari, Kapilbastu, Jhapa, Bara, Morang. More than 56% of the production is covered by these districts.
The mango production is trend is interesting. The plant booms in fruiting in every alternate year and hence the productivity too. As we observe the production trend of mango in Nepal, it can be seen this clearly that in every alternate year, the production quantity is declined. Despite the domestic production, mangoes are imported from India to Nepal. In the year 2007/08, 3306 MT (worth of the value of 20 million NRs) of mangoes were imported from India to Nepal.
Importance of mango
The importance of mango can be clearly understood through its nutritional importance and economical importance.
A. Nutritional importance
The king of fruits” mango fruit is one of the most popular, nutritionally rich fruits with unique flavor, fragrance, taste, and health promoting qualities, making it numero- uno among new functional foods, often labeled as “super fruits”
Health benefits of mango
Mango fruit is rich in pre-biotic dietary, fiber, vitamins, minerals and poly-phenolic flavonoid antioxidant compounds (Rudrappa, 2009)
According to new research study, mango fruit has been found to protect against colon, breast leukemia and prostate cancer.
Mango fruit is an excellent source of vitamin –A and flavonoids like beta-carotene, alpha- carotene and beta cryptoxanthin. Caonsumption of natural fruits rich in carotenes is known to protect from lung and oral cavity cancers.(Rudrappa, 2009)
Fresh mango is good source of potassium. 100 gram of fruit provides 156mg of potassium. Potassium is important component of cell and body fluids that helps controlling heart rate and blood pressure.
It is very good source of vitamin B6, vitamin C and vitamin E. consumption of foods rich in vitamin C helps the body develop resistance against infectious agent and scavenge harmful oxygen free radicals.
Additionally mango peel is also rich in phytonutrients, such as the pigment antioxidants like carotenoids and polyphenols.( Rudrappa, 2009)
B. Economic importance
Every year the demand of mango is increasing. Our country is unable to meet the total demand requirement in any fruit crops. A large import of mango is especially from india. Every year the price of mango is also increasing. A surplus production of mango within the country can lead to meet its remand requirement and further more earns foreign currency through export (Thapa P .K et. Al, 2008)
Post harvest problem of mango
After mangoes are harvested, they undergo various changes, and in most of the cases, undesirable changes do occurs and obviously led to the deterioration. The causes of post harvest deterioration are physical, physiological and pathological reasons and commence the losses on Mango ( Gautam and Bhattarai, 2006). Common practices of harvesting of mango make some sorts of injuries invisible or sometimes visible to the eyes. It is almost impossible to harvest and handle horticultural commodities without injuries. Mechanical cut and bruises occur during harvesting, cleaning, packaging, chemical treatment, loading, unloading, transport etc (Gautam and Bhattarai, 2006). The injuries the mango quality and serves as avenue for the entry of the pathogens. Any injuries causes stress to the mango and cause increase in respiration and ethylene production, which reduces shelf life and ultimately enhances deterioration. Ripe fruits are suitable media for growth of microorganisms. Harvesting at premature or over mature stage reduces quality and has short shelf life. Mango fruit develop fiber at over mature stage, while harvesting at premature causes physiological disorder and poor storage. For storage purpose climacteric fruits should be harvested at fully developed stage but before the initiation of climacteric rise (Gautam and Bhattarai, 2006). The mineral and nutrition level in the fruit plays important role in determining post harvest life of mango. Low level of calcium reduces fruit quality and deteriorates at faster rate (Karemera and Habimana, 2014)
1.2 Problem of study
Mango fruit is appropriate for canning purpose. It is sweet In taste and it has a high demand for export. Keeping quality of fruit is good. Nitrogen and potassium are required in larger amounts by plants (Atkinson et al., 1990). Calcium is considered as a secondary plant nutrient. It plays an important role in carbohydrate conversion into sugars and it is a constituent of cell wall (Elliot, 1996). Calcium is not considered as a leachable nutrient (Cheung, 1990). Many soils contain high levels of insoluble calcium such as calcium carbonate, but crops grown in these soils will often show a calcium deficiency (Boyonton et al., 2006). Calcium can only be supplied in the xylem sap (Banath et al., 1966). High levels of other cations such as magnesium, ammonium, iron, aluminium and especially potassium, will reduce the calcium uptake in some crops due to their antagonistic effect for their absorption (Kulkani et al., 2010).
The most commonly observed deficiency symptoms of calcium in plants are necrosis at the tips and margins of young leaves, bulb and fruit abnormalities, deformation of affected leaves, highly branched, short, brown root systems, severe, stunted growth, and chlorosis (Jones and Lunt, 1967). Calcium will be toxic if it is supplied in excess quantities (Kumar et al., 2006).
The time of harvest is a predisposing factor for the shelf life of mango fruit. The harvesting of fruit at full ripening stage is unsuitable for distant market and long term storage. during the transportation the loss of mango is very high. Mango are susceptible to bruishing and other kinds of mechanical damage ( Gautam and Bhattarai, 2006).
1.3 Rationale of study
Calcium spraying increased the productivity of mango due to the reduction of abscission (Kumar et al., 2006). It enhances the mango quality by increasing the fruit firmness and by maintaining the middle lamella cells. Treatment with calcium nitrate and calcium chloride (0.6-2.0%) delayed ripening after harvest, lowered weight loss and reduced respiration rates (Bender, 1998). Fruits storability was also improved by CaCl2 under cold storage (Wahdan et al., 2011). The pre and post-harvest application of chemicals like calcium chloride and calcium nitrate are known to influence the quality and shelf-life of fruits during storage (Gill et al., 2005).
Low fruit calcium levels have been associated with reduced post-harvest life and physiological disorders. For example, low levels have been correlated with physiological disorders of mangoes. So, to solve the problem of short shelf-life of mango fruits, different chemicals are used to delay the hastening. Gofure et al. (1997) studied on extension of post-harvest storage life of mango and they reported that the increase in calcium salts levels leads to delayed hastening but had bad effect on fruit quality by enhancing skin shriveling and reducing flavor and taste of the fruits.
1.4 Objective of the study
Reduce post harvest loss
To evaluate the different concentrations of calcium chloride on ripening of mango.
To study the effect of calcium chloride spray on shelf-life of mango.
To study the effect of calcium chloride spray on physio-chemical properties of mango.
To study the effect of calcium chloride spray on organoleptic qualities of mango.
To find out appropriate dose of calcium chloride for better post harvest of mango.
Pre-harvest spray of Calcium chloride delays the ripening of mango.
There is best rate of calcium that influences physio-chemical proprieties of mango.
2. LITERATURE REVIEW
Mango is juicy stone fruit belonging to the genus mangifera consisting of numerous tropical fruit trees, that are cultivated mostly for edible fruits ( Morton J, 1987). The majority of of these species are found in nature as wild mangoes. They all belong to flowering plant family Anacardiaceaae. The mango is native to south and south East Asia, from where it has been distributed to the worldwide to become one of the most cultivated fruits in the tropics. The highest concentration of msngifera is situated in western part of malesia and in Burma and india. It is the national fruit of india and phillipines and national tree of Bangladesh ( kostermans and bompard, 1993). Mango is important fruit tree of terai to inner terai region of our country.
Mango trees ( mangifera indica L) grow upto 35-40 m(115-131 ft) tall, with a crown radius of 10 m. the trees are long lived, as some specimens still fruit after 300 years. In deep soil, the taproot descends to a depth of 6 m, with profuse, wide-spreading feeder roots which penetrate several feet of soil. The leaves are evergreen, alternate, simple, 15-35 cm long and 6-16 cm broad; when the leaves are young they are orange pink, rapidly changing to dark, glossy red, then dark green as they mature. The flowers are produced in the terminal panicles 10-40 cm long; each flower is small and white with five petals 5-10mm long, with a mild sweet odor suggestive of lily of valley. There are over 400 varieties of mango, many of them ripe in summer while some give double fruit (mango, toptropicals.com ). The fruit takes three to six maonths to ripen.
The ripe fruits vary in size and color. Cultivars are variously yellow, orange,red or green and carry a single flat, oblong pit that can be fibrous or hairy on the surface, and which does not separate easily from the pulp. Ripe, unpeeled mangoes give off a distinctive resinous, sweet smell. Inside the pit 1-2 mm thick is a thin lining covering a single seed, 4-7 mm long. The seed contains the plant embryo( Morton J, 1987).
Mango possesee unique nutritional and medicinal qualities apart from being a rich source of vitamins A and C. besides its attractive form and appearance, delicious taste and appreciating flavor, the ripe mango fruit, according to nutritional experts, is also highly invigorating, fattening, laxative and diuretic ( Bal J.S 2006). The medicinal importance of mango can be listed as:
Mango fruit is rich in pre-biotic dietary, fiber, vitamins, minerals and poly-phenolic flavonoid antioxidantcompounds (Rudrappa, 2009)
According to new research study, mango fruit has been found to protect against colon, breast leukemia and prostate cancer.
Mango fruit is an excellent source of vitamin –A and flavonoids like beta-carotene, alpha- carotene and beta cryptoxanthin. Caonsumption of natural fruits rich in carotenes is known to protect from lung and oral cavity cancers.(Rudrappa, 2009)
Fresh mango is good source of potassium. 100 gram of fruit provides 156mg of potassium. Potassium is important component of cell and body fluids that helps controlling heart rate and blood pressure.
It is very good source of vitamin B6, vitamin C and vitamin E. consumption of foods rich in vitamin C helps the body develop resistance against infectious agent and scavenge harmful oxygen free radicals.
Additionally mango peel is also rich in phytonutrients, such as the pigment antioxidants like carotenoids and polyphenols.( Rudrappa, 2009)
Every part of mango, from root to top, is used in variety of ways. The fruit itself in the various stages of its development is used in many ways. In its raw stage, the fruit is used for extraction of tannin and other astringent products as well as for the preparation of delightful chutneys, curies and pickles (Bal, 2006). Ripe fruits are delicacy for table, while the unmarketable and inferior ones can be converted into delicious squashes, juices, nectars, syrups, jams and jellies. Canned mango slices and pulp are indeed very popular. The stones besides their use for propagation can serve as a good stock feed for cattle (Bal, 2006). The inside kernel of the stone, being rich in carbohydrates, calcium and fat can be used as a source of food for certain industrial purposes (Bal, 2006). Thus the mango is a unique fruit, and possesses all the endearing qualities which justifiably lend to it a universal appeal.
Manuring mango plant starts right from planting operation in the orchard. Liberal applications of welldecomposed organic manure can be given each year to create proper soil physical environment and on account of several other beneficial effects.
Fertilizer dose/ plant / year
Age of plants(years) FYM (kg) N (g) P (g) K (g)
1 5 100 50 100
2 10 200 100 200
3 15 300 200 300
4 20 400 300 400
5 25 500 400 500
6 30 600 500 600
7 35 700 500 700
10th onwards 50 1000 500 1000
Source: Fruit Growing ( Bal, J.S)
Entire dose of the FYM and half dose of N, P and K should be given during monsoon while the balance half is applied during the end of monsoon. Before the application of fertilizers, the weeds should be removed from basins. The mixture of recommended dose of fertilizers should be broadcast under the canopy of plant leaving about 50 cm from tree trunk in old trees. The applied fertilizer should be amalgamated well up to the depth of 15 cm. To increase fertilizer use efficiency, fertilizers should be applied in 25 cm wide and 25-30 cm deep trenches dug around the tree 2 m away from trunk. The application of micronutrients is not recommended as a routine. Need based supplementation’s are essential when these become limiting factor for production. It is advisable to apply micronutrients through foliar sprays.
Amount and frequency of irrigation depends upon the type of soil, prevailing climatic conditions, especially rainfall to be given and its distribution and age of trees. No irrigation is required during the monsoon months unless there are long spells of drought. During the first year when the plants are very young with shallow root system, they should be watered every 2 to 3 days in the dry season. Trees in the age group of 2 to 5 years should be irrigated at 4 to 5 days interval. The irrigation interval could be increased to 10 to 15 days for 5 to 8 years old plants during dry season. When trees are in full bearing stage, generally 2 to 3 irrigations are given after the fruit set. Profuse irrigation during 2 to 3 months preceding the flowering season is not advisable. Irrigation should be given at 50 percent field capacity. Generally, intercrops are grown during the early years of plantation and hence frequency and method of irrigation has to be adjusted accordingly. It is advisable to irrigate the mango plants in basins around them, which can be connected in series or to the irrigation channel in the centre of rows. The intercrops need to be irrigated independently as per their specific requirements. In monocropping of mango also, basin irrigation is preferable with a view to economize water use (Medina and Garcia 2002).
After crops are harvested, they undergo various changes, and in most of the cases, undesirable changes do occurs and obviously led to the deterioration. The causes of post harvest deterioration are physical, physiological and pathological reasons and commence the losses on fruits (Mango),( Gautam and Bhattarai, 2006)
A physical cause of deterioration refers to the external injuries in the outer surface or inner part of the produce. Common practices of harvesting of mango make some sorts of injuries invisible or sometimes visible to the eyes. It is almost impossible to harvest and handle horticultural commodities without injuries. Mechanical cut and bruishes occur during harvesting, cleaning, packaging, chemical treatment, loading, unloading, transport etc(Gautam and Bhattarai, 2006). The injuries the mango quality and serves as avenue for the entry of the pathogens. Any injuries causes stress to the mango and cause increase in respiration and ethylene production, which reduces shelf life and ultimately enhances deterioration. Ripe fruits are suitable media for growth of microorganisms.
During storage freezing injury may damage the post harvest life of mango. The temperature below less than 0°C, causes the formation of ice in intercellular region (Gofure et al 1997).
Transpiration is major factor that determines the post harvest life of fruit. Transpiration is the losses of water of economic importance. Transpiration led to loss of total weight of produce. Transpiration generally occurs through the stomata (Gautam and Bhattarai, 2006)
Continuous respiration and metabolic process exhaust the stored food materials and led to the death of tissue which causes the deterioration of fruit. Lack of oxygen during the storage also causes the post harvest deterioration of fruit and as a result off-flavor produced due to anaerobic respiration or fermentation.
Time of Mango harvesting is an important factor of post harvest longevity of fruit. The time of mango harvesting varies from place to place and it also depends the cultivar type and availability and distance to market. Producers must decide whether to harvest as soon as the market price ensures a reasonable return or to leave the crop in the field to obtain maximum yield. However, waiting too long for yield increase may drastically shorten the marketable life of the produce and lower the sale price. This balance is a critical factor in determining the grower’s income from the crop. In practice the total harvest period is very short and the grower has very little time in which to make the correct decision. Harvesting at premature or over mature stage reduces quality and has short shelf life. Mango fruit develop fiber at over mature stage, while harvesting at premature causes physiological disorder and poor storage. For storage purpose climacteric fruits should be harvested at fully developed stage but before the initiation of climacteric rise (Gautam and Bhattarai, 2006).
Fungi, bacteria and insect larvae can infect mango tree and fruits either directly or indirectly. The latter is related to phyto-sanitary problems of the crop. More than 492 species of insects, 17 species of mites and 26 species of nematodes have been reported to be infesting mango trees. Almost a dozen of them have been found damaging the crop to a considerable extent causing severe losses and, therefore, may be termed as major pests of mango. These are hopper, mealy bug, inflorescence midge, fruit fly, scale insect, shoot borer, leaf webber and stone weevil. Of these, insects infesting the crop during flowering and fruiting periods cause more severe damage. The insects other than those indicated above are considered as less injurious to mango crop and are placed in the category of minor pests (Rajans, 2000). Some of the diseases like powdery mildew, anthracnose, die back, are of economic importance in post harvest life of fruit because these disease affect the shelf life of fruit directly or indirectly. The microorganisms produce abnormality in the commodity. Pathogen not only produce but also produce ethylene gas and lead to deterioration of the mango at faster rate ( Gautam and Bhattaria, 2006).
Post harvest loss of mango in different steps
• Loss due to Harvesting Method
The share of bruising, physical damage and sap contamination in loss at this stage was 8.67%, 6.17% and 72.84% respectively (Mallik and Majhar 2007)
• Tree to Shed
At the stage of farm shed, the percentage of fruit quality losses was 72.83% due to the cumulative share of bruising (6.5%), physical damage (5.5%) and sap contamination (60.84%), while the normal fruits, free from any disorder, were 27.17% (Mallik and Majhar 2007).
• Transportation (Farm to Wholesaler)
The current study reveal that only 6.2% fruits were free from any type of disorder, while 93.8% fruits were suffering from one or the other disorder at wholesale market. On an average, losss of 7.3% fruit were normal in top layer followed by bottom and middle layers with 6.3% and 5.0% respectively. Similarly the fruit loss was minimum in top layer (92.8%) followed by bottom (93.8%) and middle (95.0%) layers (Mallik and Majhar 2007).
• Wholesaler to Retailer
7.5% fruit remained free from any disorder at the retail end while 92.5% fruit was affected with any one of the detailed factors. The most important factor causing fruit losses at the retail level in the current study was sap contamination (50.25%) followed by physically pressed fruits (15%), bruising (13.5%), physical damage (8.5%) and diseases or disorders (5.25%).
• Cumulative Postharvest Losses in Mango
Taking in account the losses mangoes at every independent stage of the supply chains and calculating the mean of all the values, according to the current study, the estimated postharvest losses of mango from harvest to the retailer were 75.36%.
It is obvious that postharvest losses increase gradually at every stage of the supply chains, however maximum fruit loss occurs at the stage of harvest and transportation from orchard to
Wholesaler. Thus, if some interventions could be introduced to reduce the losses at these two stages, the mango fruit available for consumption or export can be increased.
Role of calcium chloride in post harvest longevity of mango
Nitrogen and potassium are required in larger amounts by plants (Atkinson et al., 1990). Calcium is considered as a secondary plant nutrient. It plays an important role in carbohydrate conversion into sugars and it is a constituent of cell wall (Elliot, 1996). Calcium is not considered as a leachable nutrient (Cheung, 1990). Many soils contain high levels of insoluble calcium such as calcium carbonate, but crops grown in these soils will often show a calcium deficiency (Boyonton et al., 2006). Calcium can only be supplied in the xylem sap (Banath et al., 1966). High levels of other cations such as magnesium, ammonium, iron, aluminium and especially potassium, will reduce the calcium uptake in some crops due to their antagonistic effect for their absorption (Kulkani et al., 2010). The most commonly observed deficiency symptoms of calcium in plants are necrosis at the tips and margins of young leaves, bulb and fruit abnormalities, deformation of affected leaves, highly branched, short, brown root systems, severe, stunted growth, and chlorosis (Jones and Lunt, 1967). Calcium will be toxic if it is supplied in excess quantities (Kumar et al., 2006). Calcium spraying increased the productivity of mango due to the reduction of abscission (Kumar et al., 2006). It enhances the mango quality by increasing the fruit firmness and by maintaining the middle lamella cells. Treatment with calcium nitrate and calcium chloride (0.6-2.0%) delayed ripening after harvest, lowered weight loss and reduced respiration rates (Bender, 1998). Fruits storability was also improved by CaCl2 under cold storage (Wahdan et al., 2011). The pre and post-harvest application of chemicals like calcium chloride and calcium nitrate are known to influence the quality and shelf-life of fruits during storage (Gill et al., 2005). Low fruit calcium levels have been associated with reduced post-harvest life and physiological disorders. For example, low levels have been correlated with physiological disorders of mangoes. So, to solve the problem of short shelf-life of mango fruits, different chemicals are used to delay the hastening. Gofure et al. (1997) studied on extension of post-harvest storage life of mango and they reported that the increase in calcium salts levels leads to delayed hastening but had bad effect on fruit quality by enhancing skin shriveling and reducing flavor and taste of the fruits.
3. PROJECT ACTIVITIES (MATERIALS AND METHODS)
Study on ripening, shelf-life, physico-chemical parameters and organoleptic evaluation of mango fruits (Mangifera indica L.) Cv. Alphonso carried out at the “A’ block of mango orchard
The experiment will be carried out with Complete Randomized Design with three replications.
Alphonso trees will be sprayed with CaCl2 at 30 days and 15 days before harvest. Data on number of days taken for ripening of fruits, shelf-life of fruits, physico-chemical parameters of fruits and organoleptic qualities of fruits will be recorded.
T1: Control (no spray),
T2: 0.50% spray of calcium chloride at 30 days before harvest,
T3: 1.00% spray of calcium chloride at 30 days before harvest,
T4: 1.50% spray of calcium chloride at 30 days before harvest,
T5: 0.50% spray of calcium chloride at 15 days before harvest,
T6: 1.00% spray of calcium chloride at 15 days before harvest,
T7: 1.50% spray of calcium chloride at 15 days before harvest The details of the experimental materials used and methods applied for the investigations are presented here:
Site: The experiment will be carried out at kanchanpur district which represents the terai region of Nepal.
Variety used: Alphonso
Observation to be taken
• Number of days taken for ripening of fruit:
Days from harvesting till the ripening will be recorded.
• Shelf-life of fruit:
The shelf-life of fruit will be accounted from the date of harvesting to the shelf- life expiration date.
• Physical parameters of fruit
• Length of fruit:
The length of the fruit from stalk end to the apex of the fruit will be determined at harvest stage with the help of vernier caliper and expressed in centimeters.
• Breadth of fruit
The breadth of fruit will be determined as the maximum linear distance between two shoulders of the fruit with the help of vernier caliper and expressed in centimeters.
• Thickness of fruit
The thickness of the fruit will be measured at the linear distance between the two checks of the fruit with the help of vernier caliper and expressed in centimeters.
• Volume of fruit:
The volume of the fruit will be measured by the conventional water displacement method and expressed in milliliter.
• Weight of fruit:
Immediately after the harvest of the fruit, stalk will be removed and the weight of the raw fruit will be recovered in grams.
• Weight of fruit peel:
The ripped fruits will peel off using a knife and weight of the peel will record in grams.
• Weight of fruit pulp:
The mango pulp from the ripe fruits will be separated from the peel and the stone and the weight will be expressed in grams. The percentage weight of pulp to that of total weight of fruit will be also computed.
• Weight of the stone
The stones of ripe mango fruits belonging to different cultivars will be separated from the pulp and their weight will be recorded in grams.
• Chemical composition of fruit
The fruits harvested from each tree will be employed to estimate the chemical composition of fruit. Total soluble solids, total sugars, reducing sugar, non-reducing sugar and titratable acidity will be estimated.
Total soluble solids content of a solution will be determined by the index of refraction. This will be measured using a refractometer, and referred to as the degrees Brix.
• Total sugars
The content of total sugars present in ripe fruit of different cultivars of mango will be estimated by the phenol sulphuric acid method and expressed in per cent.
• Reducing sugar:
The reducing sugar content of the ripe mango pulp will be estimated by Di-nitro salicylic acid method developed by Miller (1972) and will be expressed in per cent.
• Non-reducing sugar
The non-reducing sugar content of the mango pulp will be calculated by the subtracting the reducing sugar content of mango pulp from that of total sugar.
• Titratable acidity
Titratable acidity will be estimated from the pulp of ripe mango fruits. One gram of pulp from each replication in each treatment will be homogenized using a pestle and mortar and the volume made up to 20 ml with distilled water. It will then titrate against 0.1N sodium hydroxide solution to a phenol phatalein end point. The acidity will expressed as per cent malic acid
• Organoleptic qualities of fruit (Standard reference to be quoted)
The ripe mango fruits of selected varieties will be subjected to organoleptic evaluation by a panel of six judges along with their signatures. The evaluation will be carried out on a 100 score scale prepared on the basis of principles of organoleptic evaluation (Amerine et al., 1965), which had points for peel colour (15 score), pulp colour (15 score), texture of pulp (20 score), flavor of pulp (20 score) and taste of pulp (30 score). The overall acceptance of the fruits will be worked out by adding points scored for each of these characters.
Statistical analysis of data
The mean values of data on all the characters will be subjected to statistical analysis by using MSTAT and the results will be presented and discussed. The level of significance on “F” test will be tested at 5 %.The interpretation of the data will be done by using CD values calculated at the probability of 5 per cent and 1 per cent.
4. EXPECTED OUTPUTS
1. Post harvest life of mango increased with pre-harvest treatment of calcium chloride
2. Research finding published and technology generated disseminated.
5. OBJECTIVELY VERIFIABLE INDICATORS
1. Efficient pre-harvest treatment of calcium chloride that extends the post harvest life of the mango identified (Research report).
• The primary beneficiaries will be the mango growers. They will get an appropriate post harvest technology for increasing post harvest life of mango.
• Businessman and industrialists based juice, jam, jelly industries will also be benefited with the availability of higher quality of mango in sufficient quantity.
• The indirect beneficiaries will be government and non government organizations, students and other related institutions.
7. RISK AND ASSUMPTION
1. The fund will be available in time.
2. Related biotic and abiotic factors will be favorable.
3. Materials will be available in time including chemical substances.
8. EXPECTED ENVIRONMENTAL IMPACT
There will be no negative environmental impact from the project furthermore there is minimization in loss of mango due to decay and damage so will be reduction in environmental pollution.
9. FACTOR PREVENTING THE ATTAINMENT OF PLANNED ACTIVITIES
• Unfavorable climatic condition for mango production.
• Conflict among project members and the surrounding population.
• If fund is not released timely.
• Well equipped laboratory unavailable.
10. BUDGET ALLOCATION
1 Communication, literature review
2 Chemical cost
3 Other instruments cost
4 Lab rent
5 Data analysis and report writing
6 Sub total
9 Grand total
11. GANTT CHART
S.N. Activities Time for implementation
Jul Aug Sep Oct Nov
Literature review and proposal development
Tree treatment with Cacl2 30 days before harvesting
Tree treatment with Cacl2 15 days before harvesting
Data collection and compilation
Publication of research output
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20. Sthapit. P , 2008. Mango in Nepal: Production Expected to increase this year.
21. Thapa P .K, Kamal D. S, Gaire R, Commodity Case Study: Fruits
Cotton is a soft, fluffy staple fiber that grows in a boll or protective capsule around the seeds of cotton plants of the genus Gossypium .The fiber is almost pure cellulose .It is one of the most important fiber crop playing a key role in economic and social affairs of the world .It is the oldest among the commercial crops of the world and also known as the king of fibers .The English term cotton derives its name from Arabic word ‘quoton’, Dutch ‘katoem’ and French ‘coton’.
Archaeologists have discovered cotton fibers more than 4,000 years ago in costal Peru and at Mohenjo-Daro in the Indus valley (Pakistan).The plant is a shrub native to tropical and sub-tropical regions around the world including the Americas, Africa and India. The greatest diversity of wild cotton species is found in Mexico followed by Australia and Africa. It belongs to family Malvaceae and tribe Hibisceae. Four cultivated species of cotton are:
* Gossypium arboretum
* Gossypium herbaceum
* Gossypium hirsutum
* Gossypium barbadense.
Current estimates for world production are about 25 million tons annually, accounting for 2.5% of world’s arable land. China is the world largest producer of cotton, but most of this used domestically .The United States has been the largest exporter for many years. The important cotton growing countries are India, China, USA, Brazil, Egypt, Pakistan, Australia, etc.
In Nepal, it is mostly cultivated in western part of the country like in Banke, Bardia, Dang, Kailali and Kanchanpur .Now the cultivation is decreasing day by day. In 1985/86, the crop was cultivated in area of 1,552 ha by 3,018 farmers and then, it was 3,426 ha in 1994/95. Likewise, in 1999/2000 the area under cotton cultivation was 875 ha and about 3,661 farmers were engaged in its cultivation. During 2009, the area and production is 100 and 59 tones, respectively. According to FAO, the area and production of seed cotton is 121 ha and 109 tones, respectively in 2010.
Cotton is grown chiefly for its fiber used in the manufacture of cloth for mankind .It is also used to make a no. of textile products like towels ,jeans ,socks ,t-shirts ,etc .It is also used for several other purposes like making threads ,for mixing in other fibers and extraction of oil from cotton seed .Cotton seed cake after extraction of oil is a good organic manure and contains about 6%N ,3%P and 2%K .Cotton seed ,cotton linters and pulp obtained during oil extraction and cotton meal are good concentrated feed for cattle
- To be familiar with major weeds found in cotton field.
- To be able to manage the problem of weed infestation in cotton production.
Weeds are the unwanted and undesirable plants which interfere with the utilization of land and water resources and thus adversely affect human welfare .They are often prolific ,persistent ,competitive and harmful .They can also be referred to as plant out of place .Usually this means that weeds grow where we either want other plants to grow or where we want no plants at all .In cropland and forests ,weeds compete with the beneficial and desired vegetation ,reducing the yield and quality of produce .Undesirable vegetation also flourishes in aquatic systems ,forestry and non cropped areas such as industrial sites ,roadsides ,landscape planting ,water tank ,etc .thus all plants may become weeds in particular situations .It is widely known that losses caused by weeds exceed the losses from any category of agricultural pest such as insects ,nematodes ,rodents ,etc .of the total annual loss of agricultural produce from various pests ,weeds account for 45% .
Many kind of weeds have found certain limited uses .however ,this is rather an anomalous situation ;for if a plant has a reputed use ,strictly by definition it should cease to be classed as a weed .A plant classed as a weed in one region may when grown in another posses some very valuable uses or in a few cases may actually be cultivate .Weeds are largely used by primitive peoples in medicine and as emergency food supplies .weeds are used as food for animals ,for ornamental purpose ,etc .weeds can also be the source of organic matter in soil and thus contribute to increase soil fertility.
WEEDS MANAGEMENT IN COTTON:
Weeds are serious and costly pest in cotton .cotton grows slowly in the spring and can be shaded out result .For this weed management is focused on providing a 6 to 8 week weed free period directly following planting.
Weed management refers to the combination of practical approaches which intend to minimize the crop losses weeds. It includes weed prevention, eradication and control of weeds from field.
a) Prevention: This includes combination of practices that deny the entry and establishment of new weeds in an area. Prevention is better than cure. The following methods are generally adopted for prevention of weed
- Use of pure crop seeds that is free from weed seed
- Use of well decomposed organic manures and mulch materials that is free from weeds.
- Prevention of movement of cattle from weed infested areas to cotton field.
- Cleaning of farm machinery before going to the field.
- Prevention of shifting soil from infested area to cotton field.
- Cleaning of the irrigation channel, drainage channel, bunds, farm road and nearby area.
b) Eradication: Weed eradication is complete removal of all live plant parts and seeds of weed so that the weed cannot regenerate the growth. This can be done by
- Destroying the species at the initial stage of introduction and growth before it produces seed and/or any propagules so that it cannot regenerate.
- Destroying the buried dormant viable seeds by fumigation, flooding, heating, etc.
c) Control of weeds: Weed control is the process of limiting weed infestation so that crops could be grown profitably and other activities of man conducted efficiently. Control method can be divided into 4 groups:
1) Physical method: This method includes the use of manual labor, animal power, fuel and different and different implements to uproot, cut, incorporate, burn and decompose the weeds to reduce their growth and infestation. The implements used in this method may vary from simple hand tools.
2) Cultural method: In this method weed free seedbed preparation, summer ploughing, adoption of crop rotation, conservation tillage, proper planting density, inter row cultivation, proper amount, method and time of fertilizer application and proper irrigation are the common practices adopted to reduce weed infestation in cotton.
3) Biological method: The control of weeds with living natural enemies of weeds is known as biological method of weed control. The bioagents are insects, fungi, fishes, etc. One of the weed of cotton, cockle bur’s natural enemy are pumpkin beetle.
4) Chemical method: This method includes the use of various chemicals to kill the weed called herbicides. Some common herbicides used in cotton field are atrazine, diuron, 2, 4-D, etc.
MAJOR WEEDS OF COTTON:
Major weeds of cotton include, pig weeds, crab grasses, nut sedges johnsongrasses, cockle burs, morning glories and plants in sida complex. Plants in sida complex are the only weeds that have become relatively more serious since 1965, whereas barnyard grass has diminished in importance in the same period. The major weeds of cotton, their harmful effects and control methods are described below:
Amaranthus retroflexus L. (Redroot pigweed)
It is a broad leaf weed. It is found in 46 countries, is considered as a serious weed in 16 countries including USA, Canada, and Mexico. It is a roughish, somewhat pubescent annual, with a long fleshy, red or pinkish taproot and pink or white rootlets. The stems are often erect, 1-2 m high, are simple or branching freely, if not crowded, greenish to reddish, with the lower part being thick and the smooth upper part often very hairy. Leaves are alternate, long stalked, sparsely hairy, ovate to rhombic ovate, dull green above the lower surface with prominent white veins. A vigorous plant may produce 100,000 seeds. Commonly found in cultivated fields, orchards, roadside and open disturbed habitats where annual weeds predominate. Seldom grows in shade.
- Dry hoeing with a hand hoe or spades 5-6 weeks after sowing is effective.
- Several soil applied and foliage applied herbicides atrazine, perfluidone are effective against this weed.
Cyperus rotundus L. (Nutgrass, Purple nutsedge):
It is very persistent sedge. It is World’s worst weeds occurring in 52 crops in 92 countries. It is distributed throughout the tropics and subtropics. The height ranges from 15-60cm, is swollen and thick at base. Leaves are smooth, shiny dark green and grooved on the upper surface. Roots are fibrous and extensively branched. It is sensitive to shade and grows well in wet and dry soil and warm climates.
- Mechanical method is not effective, herbicide which translocate rapidly into the tubers to prevent their regeneration are most effective in controlling.
- 2, 4-D or MCPA is effective @2-5 kg/ha.
- 2, 4-d sodium salt @4kg/ha gave complete control.
- Soil applied herbicides; atrazine and perfluidone give satisfactory result.
- EPTC can also be used.
- Soil incorporation of imazaquin (150-250gm/ha), chlorimuron (50-100gm/ha) and halosulfuron-methyl (75-150gm/ha) provides good control of tuber growth.
- Post application of chlorimuron (10-20gm/ha) or imazethapyr (50-100gm/ha) can also be done.
Sorghum halepense L. (Johnson grass)
It is an erect perennial grass which reproduces by large rhizomes and by seeds. Root system is freely branching, fibrous with stout rhizomes. Stem is erect, stout, 0.5-2m tall, arising from creeping scaly rhizomes. Leaves are alternate, simple, smooth, 20-25cm long and 1.5-2cm wide. This grass is heavy seed producer, grows well on arable land and along irrigated canels.also troublesome weed in sugarcane, maize, etc.
- Application of dalapon or asulam at an interval of 20 days.
- Mechanical cultivation of the infested soil, followed by foliage application of glyphosate or dalapon+ammonium sulphate on regrowth helps in effective eradication.
- Two ploughing and two discing followed by soil incorporation of trifluralin can give good control.
- Pre application of EPTC+atrazine, alachlor, diuron, fluchloralin, trifluralin and pendimethyline.
- post application of nicosulfuron (35gm/ha) and primisulfuron (49gm/ha).
Digiteria sanaquinalis L. (Crab grass)
It is an annual grass. Its clums are stout, usually decumbent at the base, smooth 30-90cm long when prostrate. Leaves are long and somewhat hairy. It flowers between July and September and is prolific seed producer. It can thrive well under both tropical and temperate climate. It can grow in moist areas as well as under dry and hot weather condition. Covers ground very fast.
- Mechanical method alone not effective.
- Application of diuron, butachlor, EPTC, metribuzin, oxadiazon, etc.
- Pre soil incorporation of butylate tatrazine, alachlor+linuron and alachlor+chloramben. Pre application can be done 1to 2 kg/ha.
- Post application of paraquat.
Xanthium spp. (Cockle burs):
It is also a major weed of cotton. It belongs to family asteraceae and native to the Americas and eastern Asia. It is herbaceous annual plants growing 20-47 inch tall. The leaves are spirally arranged with a deeply toothed margin. The seeds are produced in hard, spiny, globose or oval double chambered single seeded burs. They stick to the clothes and animal body and are carried all around the world by travelers. This weed is noxious for animals.
- Hoeing the area where cockle burs grows in the spring.
- Applying pre emergent herbicides like flumetsulam and metribuzin.
It is the common name for over 1000 species of flowering plants in the family convolvulaceae. It is a perennial weed. It develops thick roots and tends to grow in dense thickets. They can quickly spread by way of long, creeping stem and complete with cotton plant for nutrients and sunlight. It is characterized by attractive purple, pink and white flowers.
- Root system should be removed by hand weeding.
- Herbicide, glyphosate (round up) can be done.
- Biological control can be done by golden tortoise beetle.
Caustic weed (Chmaesyce drummondii)
It is a minor weed of cotton that competes for nutrients and water and at high density can reduce cotton yields. It is relatively easily controlled and is often ignored but it is a persistent weed that may become more problematic in reduced input system.
Stomp and diuron give the best control of the residual herbicides, with diuron giving good post emergence control as well as some pre emergence control of caustic weed. Glyphosate (round up) also give post emergence control of caustic weed in an irrigate field.
Hence, I found out that cotton is very sensitive to weeds. Weeds are very serious and costly pest in cotton. This drastically decreases the yield of cotton production. It is reported that up to 45% loss is obtained in cotton due to weeds. I found out that the major weeds that affect cotton fields are pig weed, crab grasses, nut sedges, Johnson grasses, cockle burs, morning glories, etc. They compete with the cotton plant for nutrition, sunlight and water as a result they cannot grow properly. Not only this, caustic weed i.e. minor weeds are also affecting the cotton since they are being ignored.
So, for this, I found weed management at most. It includes preventive measure along with the control measures. Preventive measures include selecting seeds of cotton which are not mixed with weed seeds and ploughing field properly. But this alone is not sufficient if the infestation is high. Manual weeding should be regularly done in 3-4 weeks interval interval by using hoe or spade. Weeds can also be controlled chemically by using herbicides. Herbicides are pre emergent and post emergent, the combination of both spray provide best result.
- Chapman S.R. and Carter L.P., Crop production, principle and practices (2000), Surgeet Publication Co. Pvt. Ltd.
- Singh C.et al., Modern Techniques of Raising field crops, 2nd edition, Oxford and IBH Publishing Co. Pvt. Ltd
- Rao V. S., Principles of weed science, 2nd Edition; Oxford and IBH, 2000 Publishing Co. Pvt. Ltd., New Delhi.
- Gururaj Hunsigi and K.R. Krishna ;Science of field crop production
- King Lawerance J., Weeds of the world, Wiley Eastern Private Ltd.
- Lecturer note provided by Mr. T.N. Bhusal and B.B. Adhikari.
- Weeds by common Name. Retrieved from:
http://www.cottoncrc.org.au > Home> Publication > weeds identification tools >
Weeds by common names. Retrieved on 2 feb 2013.
- Retrieved from:
In context of Nepal, where there is limited research in the field of soil science, few works in the systematic classification of soil, where still majority soils are unclassified, and this assignment given by respected sir Dev Raj Chalise has really created interest towards the Nepal’s soil and also knew the major soil orders, suborders, groups. So first of all I would like to thank him. Similarly, thanks goes to respected sir Ram Kumar Shrestha for his ideas, sharing about indigenous and scientific soil classification system of Nepal. I am also grateful to Santosh Pathak who suggested me some popular websites regarding the types of soil found in Nepal. Similarly thank goes to my classmates for their kind support and cooperation.
I take the responsibility for errors that remain, and I would be grateful if they are brought to my attention in a constructive fashion.
Soil is a natural body of minerals and organic matter occurring on the surface of the earth that is the medium for plant growth and having ever-changing properties in response to many physical, chemical and biological processes going on over a geological period of time. There are different types of soil in Nepal. Various factors such as geology, climate and vegetation types have resulted in variations in soil properties. There is very limited research about soils in Nepal. So far, various types of soil found in Nepal are alluvial soil, lacustrine soil, rocky soil and mountain soil. Alluvial soils in the terai and in river basins. This alluvial soil is very fertile in nature because it is formed by the materials deposited by rivers. The sandy and gravel soil are found in churiya where gravel and conglomerate are predominantly found. This is not fertile soil. The lacustrine soil found in the Kathmandu valley. The mountain soil is formed by where boulders, sands and stone brought by glacier are found. It is also not fertile. Once a soil has been described, the next step is to classify it so that specific information regarding the soil can be communicated locally, nationally and internationally. Nepalese farmers have long used a traditional system of soil classification based on soil color, texture and water regime and within their own village can communicate soil management effectively (Tamang 1991).
The dominant international soil classification system used in Nepal is soil taxonomy. The system permits identification in the field rather than in a laboratory, it is universal in that it encompasses all of the soils found in the world and it is easy to translate into other national and international soil classification systems. The soil taxonomy classification is based on diagnostic horizons and their significance to soil pedogenesis. In 1986, a Land Resource Mapping Project (LRMP) carried countrywide survey and produced a soil classification report based on USDA soil taxonomy. It reported 14 soils group covering the 4 soil orders encountered in Nepal. They are mainly Entisols, Inceptisols, Mollisols and Alfisols. Soil orders Spondosols, Histosols, Ultisols and Aridosols are occasionally found.
- For preparation of this work “An Assignment on Major Soils Found in Nepal”, I follow most of the books and few journals available at lamjung campus library that covers the soil types and its classification. This helps me developing the ideas regarding the soil types of world and Nepal too.
- Similarly most of the information related to soil types of Nepal was retrieved from websites.
- I discussed the types of soil with my classmates, who had shared their ideas about soil types and system of soil classification in Nepal.
- Some information on the types of soil was referenced from the lecture note provided by Janma Jaya Gairah.
Major soils of Nepal
The soils of Nepal include four major orders and fourteen groups. This classification of soil is carried out by LRMP, based on soil taxonomy developed by US. The brief description of these major soil orders and group is described briefly.
These are the youngest and least developed soils. These are the soils found on hill sides and adjacent to river courses and on the steeper, less stable slope throughout the mountain regions. These are the soils formed through deposition of colluviums and alluvium and are present throughout the country. This category of soil may also be find at constructions site. The parent materials are not exposed to soil forming factors. Soil productivity ranges from very high for certain entisols formed in recent alluvium to very low for those forming in shifting sand or on steep rocky slopes. (Brady & Well, 13th edition, page no.88). Lack of clear soil horizons is the distinguishing feature of these soils. Entisols are worldwide dominant soils. Fluvents, orthents and fluvaquents are the major groups of entisols found in Nepal.
Fluvents: Fluvents are the entisols that have recently been deposited by river sedimentation. They tend to show little or more pedogenestic development and often exhibit strong evidence of recent sedimentation. Textures of these soils are generally coarse sandy with considerable inclusions of gravel within most of mountainous regions. Depending upon the type of materials carried by the rivers they can be calcareous or non-calcareous. Acasia are commonly found in these soils. Fluvents are occasionally cultivated –although the risk of crop damage or destruction is a constant threat during the monsoon.
Orthents: Orthents are common throughout the mountainous regions of Nepal. They also describe those surfaces where older soils have been seriously eroded by surface erosion and origin diagnostic horizons are absent. Generally orthents are found on steep slopes (over 30 degrees) or where landslide runouts have been deposited. As the soil develops it is constantly removed by erosion. They are shallow near the bedrock, coarse textured and poorly vegetated. Alnus is very well suited to such soils in Nepal. These soils are used for grazing, fodder and firewood collection. Under the areas of gentle slope can be quickly reclaimed for agriculture, while steeper slopes are rapidly reinvaded by pioneer vegetation. In general the Himalayan landscapes have a much higher proportion of orthents than other mountain regions of the world. This is because of the exceptionally dynamic hill slope processes that occur in the Himalayas.
Inceptisols are by far the most important soil order of Nepal. This Positioned on more stable landscapes than the Entisols, both agricultural and forestry uses are common on these soils. The relative stability of these landscapes permits some leaching of topsoil and weathering of the subsoil. Inceptisols show more significant profile development than Entisols, but are defined to exclude soils with diagnostic horizons or properties that characterize certain other soils orders (Brady & Well, 13th edition, page no 92). Inceptisols covers 9% of world land area. Major soil groups in the Inceptisols order found in Nepal are briefly described below.
Aquepts: Aquepts are relatively stable soils that are strongly affected by a high water table- at least during the monsoon season. Subsoil is under anaerobic conditions for long periods and this inhibits the plant growth but is conductive to rice production. Depending on the depth and variation of the water table over the year, different cropping systems are possible. Those areas of terai that still have high water tables late in the fall cannot take advantage of some of cash-cropping opportunities. Farmers tend to grow two rice crops in these areas. Aquepts are common in lower terai, in stable, low relief areas and are commonly associated with infilled back water channels.
Ochrepts: These are the commonest soils in the terai as well as in the middle hills, mostly below 1500 meters (higher on south facing slopes) and have developed on the acidic or neutral bedrock including lacustrine deposits. They have well developed B horizon and base saturation below 60%. They are the single-most common soil found in country and is extensively used for agricultural production. Ustochrepts with high base saturation are most prevalent in the Far Western and Mid Western Development regions of Nepal, where the climate is considered to be sub-humid (Annex 2, classification of Nepal’s soil, icimod.org). Subgroups under Ochrepts are described below.
Dystrochrepts and Udochrepts: Dystrochrepts and Udochrepts have a lower base saturation percentage and are more acidic. They are more commonly found in Central and Eastern parts of Nepal, where more humid conditions create stronger leaching conditions. It is in the Dystrochrepts and Udochrepts that the problems of soil acidification are most severe. Erosion control on the hill slopes is a must to maintain the productivity of Dystrochrepts.
Cryochrepts: Cryochrepts are common at elevations above 3,500 meters, on moderately sloping lands throughout the country. They are of no importance for agriculture production.
Eutochrepts: Eutrochrepts soils are similar to ustochrepts but developed on calcium rich parent materials.
Umbrepts:Umbrepts are the dark colored Inceptisols that usually occur above 2,000 m (1,500m on northern aspects). They have low base saturation and high organic matter levels in the surface soil. If organic matter oxidized off, their natural acidity becomes limiting to the growth of many agricultural crops. Subgroups under Umbrepts are described briefly below.
Haplumbrets: Haplumbrets are the soils of high and middle hill regions (3,500m) and developed in cool temperatures on the acidic bedrocks under mixed forest. They have low base saturation. Soils under forest and on steep slopes are shallow and stony but the cultivated ones are fertile due to a high organic matter content, which inactivates the toxic effect of aluminum by its chelating action. Soil fertility-is maintained by grazing animals, and leaving fallow for 2-3 year periods. Barley, millet and potato are the main crops grown in this soil.
Cryumbrepts: Cryumbrepts are also the soils of high Himalayan and high hill regions generally found above 3,000m but, depending on the local climate altitude vary. Soils of this group have dark A horizons, high organic matter with wide C/N ratio low base saturation and contain no free carbonate. They are silty in texture. These soils are under snow for at least three months of the year. Vegetation ranges from monsoon grasses to Rhododendron and Betula in this type of soil. Ares under these soils are extensively used for seasonal grazing.
Spondosols consists of spodic horizon (Bh,Bs). they are rare, but are important to pedologists as they indicate a stable but strongly leaching environment. Spondosols have strong reddish or black subsoil in which iron and organic have been deposited after initial leaching from the surface soil layers. They occur on stable landscapes at elevations above 3,000 meters where conifers dominate the forest. The best developed Spondosols in the country were sampled 1 km north of the old Tengboche monastery in the khumbu area. They were cryorthods (Annex 2, icimod.org). Agriculturally they are of very little importance. Spodosols have higher proportion of organic acids which accelerates weathering. This result in leaching of base cations. So Spodosols are not fertile soils.
Soils with high organic matter content, usually under thick grass or forest, dark colour and high base saturation are classified under Mollisols. They develop on basic parent materials at higher elevations. They are formed on calcium rich parent materials and throughout rapid base recycling and/or low leaching, have maintained their high base saturation. Mollisols in humid regions generally have higher organic matter content and darker, thicker mollic epipedons than their lower-moisture-regime counterparts. Mollisols have been found sporadically in the Sal forest of upper terai and southern exposed grassland sites in western Nepal at higher elevations. Vegetation removal for cultivation results in the rapid oxidation of the organic matter in the surface of these soils and they are over time converted to Ustochrepts. Some groups under Mollisols are as follows:
Haplustolls: These are common in subtropical mixed forest of terai and inner valleys. They develop on alluvial materials and are distinguished by a soft and dark colored mollic Ah horizon with high base saturation and a well developed Bm horizon under an ustic moisture regime. Haplustolls develops under forest but not under grassland. These soils are generally fertile and have high productivity for few years but later yield of crop decreases as organic matter decreases.
Cryoborolls: These differ from Haplustolls mainly in their development on base rich parent materials under thick grassland of the high mountain in high Himalayan regions. They are found in cooler climate and an udic moisture regime.
Alfisols are those soils with significant pedogenetic development, with obvious trans-located clay in the subsoil and a high base saturation percentage. Alfisols are characterized by a subsurface diagnostic horizon in which silicate clay has accumulated by illuviation (Brady & Well, The Nature and Properties of Soils, 13th edition, page no 106). Alfisols are common but do not make up a large percentage of the soils. They represent the most mature landscape positions throughout the sloping lands of the mountain regions and also on older alluvium. The great groups of Alfisols found in Nepal are briefly described below:
Rhodustalf: They are the strong red soils common on ancient terraces, are among the oldest soils found in Western Nepal. They are also known to resource managers because of their tendency to crust on the surface after tillage. These soils have problems with phosphorous fixation and are occasionally subject to severe gullying. The extensive gullying found in Jajarkot on Bheri River in Mid Western Development Region shows the extent to which gullying and land degradation can proceed. Strong local relief, low infiltration rates, slow permeability of subsoil due to clay accumulation and occurrence of high intensity rainfall are dominant characteristics that results in the gullying of these soils.
Haplustalfs and Hapludalfs: The soils that do not meet the color criteria for Rhodic, soils are classified as Haplustalfs and Hapludalfs. Hapludalfs are found in the area just north of Godavari on the southern edge of ancient lake basin that once covered Kathmandu Valley.
Only one Ultisol of any significance occurs in Nepal- the Rhodudult. Its properties are identical to those of the Rhodudalf, except that it has a low pH and a low base saturation. These soils are restricted to the old Tars in Central and Eastern Nepal, and they represent the oldest most weathered soils found in Nepal. The Jhikhu Khola just east of Kathmandu, is set between major terrace systems of Rhodudults. These soils are important to distinguish because soil acidification rapidly occurs through the use of chemical fertilizers. There is also considerable evidence that phosphorous management will be a serious problem as cropping intensity increases. Ultisols can be found in diverse climate from humid temperate to tropical climate. This soil is more weathered and acidic more than Alfisols but less than Spondosols.
Aridisols occupy a larger area globally than any other soil order (more than 12%) except Entisols. Water deficiency is the major characteristic of these soils. The soil moisture level is sufficiently high to support plant growth for no longer than 90 consecutive days. The natural vegetation consists mainly of scattered desert shrubs and short bunchgrasses. Soil properties, especially in the surface horizons, may differ substantially between interspersed bare and vegetated areas (Brady & Well, 13th edition, 3.10 1st paragraphs). These are the soils that are dry for more than nine months of the year. They exhibit very little in the way of weathering and usually have free calcium carbonate and other salts at or near the surface. There is high accumulation of sodium salts. Aridisols are restricted to the rain shadow areas of the main Himalayan massive, where annual precipitation is less than 300 mm. The areas north to Jomsom in the Mustang district are dominated by Aridisols. With irrigation, in special microclimatic pockets, they can be productive: although the vast majority of Aridisols are covered with extensive grazing pastures at this time.
Indigenous classification of soil and agricultural land
There is a systematic criterion for distinguishing soils according to landform position, based on slope, elevation and drainage. Topsoil colour, texture and terrace type are the most dominant criteria for local land classification and soil fertility management. Farmers also use broad climatic regimes to differentiate climatic conditions. These are based on elevation and aspect, which relate to temperature and which is in turn one of the most important factors influencing the choice of crops to be used in the rotation sequence, crop production and length of the growing.
Table: Broad classes of Nepal soil with their native vegetation-
Broad soil classes
Mean annual air temp. (°C)
Shorea robusta, Pinus roxburghii
1 200–1 600
Pinus roxburghii, mixed broad leaf forest
1 600–2 200
Oak (Quercus) mixed forest
Soil colour can be used as a key distinguishing criterion by farmers. Some of the colour differences relate to the age of the soil, the origin or parent material, and the carbon content. Farmers use major topsoil colours to differentiate soils. The colour categories noted by the farmers are a partial indication of organic matter content in the soil. At higher carbon content the soil colours are usually darker, the moisture content and cation-holding capacity are higher, and the structural stability of soil aggregates is greater. In addition, the very old soils in Nepal are deeply weathered and contain significant portions of Fe and Al. the former gives rise to the red soils which have a significant portion of kaolinite and distinct physical properties. Because of the long leaching processes, the red soils are generally low in phosphorous. The various types of soil colors found all over Nepal is given in table below.
Local colour classification
Munsell Soil Colour Chart
10 YR 3/1–4/1 –dark greyish brown-very dark greyish brown
2.5 YR 4/6–5/6 – red
Haluka rato mato (light red)
5 YR 5/6–6/6-yellowish red-reddish yellow
Khairo mato (brown)
7.5 YR 4/2–5/2- brown-dark brown
10 YR 5/1–5/2- grey –greyish brown
Kharani mato (light grey)
7.5 YR 7/10 YR 7/7- light grey
Jogi mato (yellow)
10 YR 6/6-7/6–8/8 – brownish yellow-yellow
Among the most important physical properties of soils considered by farmers is soil texture. Soil texture involves the size of individual particles and arrangement of soil particles into groups or aggregates. These properties determine nutrient supplying ability of soil solids and the supply of water and air necessary for plant root development activities. The size of particles in mineral soil (texture) is not readily subject to change, and remains constant. The farmers are aware of the fact that the texture of a given soil can be changed only by mixing it with another soil of different textural class. Farmers incorporate large quantities of sand and sill through irrigation water to improve the physical properties of red day soils for potato cultivation. The textural classes differentiated by farmers in the field are listed in Table below and their equivalent USDA soil texture classes are also provided. The farmer’s textural classifications are used primarily for crop selection and soil management. Heavy textured (chimte) soils require higher labour inputs then light textured (domat) soils for ploughing and other cultivation activities. Moisture content in relation to texture is also used as an index of workability of the soil.
Indigenous terms for texture classification
USDA Texture Class
Sandy clay loam
Very fine (clay) soil
Summary and Conclusions:
The vast diversity of soils can be found in Nepal. This diversity causes the difficulty in classification of Nepal’s soil. Most of Nepalese farmers use indigenous knowledge based on soil color, soil texture, consistency and depth for identification and classification of soil. Most indigenous classes can readily be converted to commonly used scientific classification. Generally two methods are popular for classification of soil. The first one is Soil taxonomy developed by US soil survey staff (1975) and other is FAO/UNESCO system. The countrywide survey carried by LRMP in 1986 reported 14-soil group covering the 4 soil orders encountered in Nepal. They are mainly Entisols, Inceptisols, Mollisols and Alfisols. Soil orders Spondosols, Histosols, Ultisols and Aridisols are occasionally found. Entisols are the least developed soils generally found on hill sides and river courses. These soils have not much agricultural importance. Inceptisols are the soils important for agricultural and forestry use. Ustochrepts (group occurs in Inceptisols) are present in Far-Western regions of Nepal. Dystrochrepts and Udochrepts are common in Central and Eastern regions. Mollisols are common in Western Nepal at higher elevations. They are rich in organic matter and base. Alfisols are found in mountainous regions of Western Nepal. Gullying is the major problem of this soil. Ultisols are acidic and have low base saturation so they have not much agricultural importance. Aridisols are the dry soils found in higher altitude such as Manang and Mustang districts of Nepal where annual precipitation is less than 300mm.
The soil which covers the earth is comprised of many individual soils each with different properties. These properties are associated with horizontal layers, found in soil profile. These horizons reflect the physical, chemical, and biological processes of soil during their development. Knowledge of the kinds and properties of soils around world is critical to humanity’s struggle for survival and well-being. This classification helps in identifying the basic characteristics of soils and also has agricultural as well as pedological significance. Cropping system can be planned depending upon the type of soil. The classification of soil also helps in promoting forest plantation programs.
ü Brady, Nyle C., and Ray R. Well. The Nature and properties of Soil, 13th edition, Singapore: Pearson Education, 2002.
ü Bishwas, T.D., and Mukherjee, S.K. Textbook of soil science, 2nd edition, New Delhi: Tata MC Graw Hill Publishing Company ltd, 2001
ü Lecture note on Soil physics, Genesis and Classification: Janma Jaya Gairah.
ü Front line: classification of Nepal’s Soil. Retrieved from http://www.lib.icimod.org/record/22779/files/c_attachment_195_2263.pdf, retrieved on 12/1/2013.
ü Nepal soil types, retrieved from http://www.newworldatlas.blogspot.com/2011/08/nepal-soil-types.html
ü Pariyar Dinesh, “country pasture/ forage Resource Profiles.” Retrieved from http://www.fao.org/ag/AGP/doc/counprof/Nepal/Nepal.html
Cotton is shrubby plants of the genus Gossypium, having showy flowers and grown for the soft white downy fibers surrounding oil rich seeds. Cotton is one of the most important fiber crops playing a major role in economic and social affairs of the world. It is oldest among the commercial crops of the world. Cotton (Gossypium spp.), is the king of fibers, usually referred as white gold. Cotton is warm season crop mainly grown in tropical and subtropical regions of world which belongs to Malvaceae family.
Cotton has been a crop of importance from the days of yore. Excavations of Indus valley civilization are testimony of cotton use more than 5000 years ago. Cotton is chiefly grown for its fiber used in manufacture of cloth. It is also used for various purposes like making threads, for mixing into other fibers and for extraction of oil from cotton seed. Cotton seed cake is the good organic manure which contains 5% N, 3% P2O5and 2%k2O. Cotton stem can be used as organic manure or fuel. In Nepal cotton growing areas are Dang, Banke, Bardiya, Kailali and Kancahnpur. Modern Cotton cultivation was initiated in 1969/70 in Nepal. In 1976/77 only 50 growers were involved in cotton farming in 8 hectares of land which increases to 3,400 hectares including 8,830 farmers in 1994/95. There after the area and production of cotton is radically decreased and reached to 135 hectares and 135 tons in 2010/11. Various textiles industries of Nepal are mainly dependent upon the imported cotton because the domestic cotton production is not sufficient to fulfill national demand. Mainly the problems of disease and pest, cultivation techniques, very limited research for introduction of new high yielding varieties, lack of processing units and reasonable price are the major constraints for the lower production of cotton in Nepal.
According to classification by Hutchinson (1947) the following four cultivated species contain almost all varieties of cotton cultivated.
- Gossypium arboreum (n=13)
- Gossypium herbaceum (n=13)
- Gossypium hirsutum (n=26)
- Gossypium barbadense (n=26)
ü To know the different methods of irrigation in cotton field.
ü To know the correct time for irrigation/ irrigation scheduling.
ü To be familiar with the effects of water logging in cotton field and ways to minimize its impact.
Crop Water Use:
Water need in cotton varies with cultivar, length of growing season, temperature, sunshine hours, the amount & distribution of rainfall and the characteristics of soil. The cotton plant has deep and extensive root system. Root zone may go down to a depth of 180 cm and laterally expand as much and make use of water effectively from deeper soil layers. The root system is however, restricted in clay and poorly drained soils. The dynamics of water use pattern for cotton (with 160 days duration) shows that with the advancement in crop growth, the water use increases progressively from 2.5 mm/day in seedling stage, 2.5 to 6.2 mm/day from squaring to first bloom, and goes to a maximum of 6.2 to 10 mm/day in peak flowering and decreases to 5.1 mm/day thereafter during boll development and falls below 2.0 mm/day during boll bursting stage. In terms of percentage of total seasonal water use, crop water requirement is 20 % till 1st flower, 40 % during 1st flower to peak flower, 30 % during peak flower to bursting of few bolls and only 10 % till maturity. The total water requirement for cotton is 700-1200 mm depending upon climate and crop growing period. In order to produce high yield, the cotton plants require 5-8 thousand cubic meter of water per hectare during period. The cotton plant can take more than 20,000 liters of water to produce 1 kg of cotton; equivalent to a single T-shirt and pair of jeans (WWF Report, 2003). This proves that water requirement of cotton is high.
Cotton’s water requirement is determined by the location, species and environment where it is being grown. Similarly, the dryer and hotter the environment, the more water the plant requires. A desert like environment with high temperatures and low humidity will result in high water requirements ranging from 40 to 50 inches of water per year. A more humid and temperate environment often results in lower water requirements between 20 to 30 inches. When water is available, its daily consumption by transpiration and soil evaporation in the cotton field averages about 1/5 inch per day. Maximum daily usage ranges from ¼ to 2/5 inch at the peak of growth in mid-summer. Thus, for higher yields, from 24 to 42 inches of water in the soil from rainfall or irrigation is used in growing season. (John H. Martin et.al, 1976).
Irrigation in Cotton Field:
Hansen et al (1980) defined irrigation as artificial application of water for the purpose of supplying moisture essential to plant growth.
Irrigation water management can be defined as the integrated process of intake, conveyance, regulation, measurement, distribution, application and use of irrigation water to farms and drainage of excess water, with proper amount at right time for the purpose of increasing crop production and water economy in conjugation with improved agricultural practices. (S.R Reddy, principles of Agronomy, 2001). Adequate soil moisture is a must at sowing and pre sowing irrigation is necessary if stored soil moisture in the profile from preseason rainfall is not adequate. Frequent irrigation to keep the soil moisture from dropping much below 50 percent of its field capacity is desirable. In hot and dry climates, this requires irrigation every 8 to 16 days. Moisture stress resulting from the lack of or an excess of water early in the growing season will restrict root and crop development (pace et al. 1999). Abrupt changes in soil moisture will adversely affect growth and cause fruit shed.
Estimated impact of severe deficit moisture stress on fruit and fiber development (Hake and Grimes, 2010)
|Fruit Stage||Retention||Impact on:
|Square initiation||Moderate||Minimal||Loss-fewer and smaller bolls|
|Boll- 0 to 30 days of age||Severe||Severe||Loss- short staple and high micronaire|
|Boll -31 to 60 days of age||Minimal||Moderate||Loss- immature fiber|
|Boll opening||None||Minimal||Hasten maturity|
It is important to work out an economically feasible and technologically efficient irrigation scheduling for optimum water use under any given set of agro-climatic condition for realizing higher crop/water productivity. Therefore, irrigation scheduling should be based on crop, soil air, soil characters and plant water relations.
1. Use of Indicator plant:
Crops like sunflower and tomato show stress symptoms earlier than others since these are highly sensitive to water stress. These crops are planted at random throughout the field and scheduling of irrigation can be made based on the stress symptoms noticed in these plants. If the plants fail to recover in the afternoon following wilting of leaves during the normal mid-day hot weather, it is a sure sign for immediate watering. Even the cotton plant can act as the indicator in itself for irrigation scheduling. Here a pit of 1.5 x 1.5 x 1.5 m is dug within the field in a most frequently visited location and the dugout soil is mixed with 5 % sand and is filled in and the level of pit is brought to approximately original level (of compaction) and a few cotton plants are planted with normal spacing in this pit. These plants normally start wilting under moisture stress before the rest of the plants in the same field, and irrigation scheduling is made observing the wilting symptoms in these. This technique of determining irrigation in cotton field can be one of the most important tool for increment of cotton production in Nepal.
2. Critical stages of plant:
Squaring, flowering and boll development are the critical stages for water at which irrigation is applied after giving the due allowances for the rainfall. Irrigation at 10 to 12 days interval during these stages seems to be the optimum. Irrigation should be curtailed in the early stages to prevent excess vegetative growth since it leads to stunted growth and delays in formation of fruiting parts. A planned moisture regime during the crop growth period promotes efficient root system, optimum vegetative growth, reduced boll shedding and uniform bursting in short period. Amongst three different stages of the crop, irrigation at boll development period showed the highest WUE and IUE thereby revealing the boll development period as the most critical for moisture stress. As the number of irrigation increased from one to more, IUE decreased because of non linear response yet seed cotton yield increase numerically although non-linearly. (K. Sankaranarayanan et.al, 2007, Central Institute for Cotton Research, Coimbatore)
Depending on climatic condition and soil type etc, irrigation at 10-15 days interval for light soils and 15-25 days for medium & heavy soils is normally recommended.
- The cotton plant needs irrigation or water when the leaves turn to a dark or dull bluish green color followed by wilting during the hot part of the day.
- A need of water is evident when vegetative growth decreases to the point where flowers are opening near the top of the plants. Lack of adequate moisture at these stages may result in premature flower drop, boll shedding and poor development of bolls.
3. Soil moisture depletion and climatological approach:
Irrigation schedules based on percent depletion in available soil moisture (50 to 75% depletion) or soil water potential of 0.5 bars in a soil profile of 30 cm depth is recommended for cotton. Cotton irrigated at 75% depletion of available soil moisture results higher yield. On climatological approach, scheduling of irrigation at 0.40 and 0.60 IW/CPE (Irrigation Water/Cumulative Evapo-Transpiration) ratio during vegetative & reproductive phases respectively is recommended.
4. Soil texture:
Six to eight irrigation’s is recommended in clay or clay loam soils for better yield. Similarly, it requires thirteen to fourteen irrigation’s for red sandy soils because water holding capacity of light textured soils is less.
Various methods of irrigation is practiced in cotton production depending upon soil characters, availability of technology and amount of water availability. Some of methods of irrigation are described below.
It is traditional method of irrigation, mostly practiced by Nepalese farmers where water is directly allowed from the channel into entire field. The water requirement is comparatively high than other methods.
This is most common and ideal method of irrigation in cotton field. It is well adapted to deep soils that are nearly level or have uniform & moderate slopes. Furrow or basin irrigation often produces higher yields than other does. This method is more effective in saving water (20-30%). In this method, the salt moves away from the furrow and deposited on the top of ridges. Cotton being more sensible to soluble salts, its risk can be minimized adopting furrow irrigation. Loam and clay loam soils are best adopted to furrow irrigation because the water holding capacity and intake rate are generally within the range that will permit uniform distribution of water. Furrow irrigation is not suitable for very sandy soil due to high intake rate.
III.Alternate Furrow Irrigation:
In this method, the crop is planted just like in the conventional method as there is no variation in spacing but variation in water application (areas). Water is applied in alternate rather than in all furrows (Irrigating odd & even furrows alternatively). Thus, 1st irrigation is applied in furrows which do not receive the 2nd irrigation and so on. This reduces surface runoff and leach salts from bed. As water flows into alternate furrows, it also moves into furrow bed and cross the bed into the non irrigated furrow in an action called subbing.
Alternate furrow irrigation applies 29 percent less water than do every furrow irrigation in silty clay loam. When every furrow id irrigated, salts tend to be carried into the seedbed. But in alternate furrow irrigation, the subbing action carries salts through the furrow bed where they accumulate along the outer edges, away from the seedbed, reducing salinity.
This method is used in diverse soil types, however, is more suitable for porous soils, water scarcity areas and undulated lands. Since the water is applied daily/alternate days at low rate and at low pressure (up to 1 kg/cm2) over a long period of time and directly into the vicinity of plant roots, it maintains the soil moisture level around the root zone at/close to field capacity. Drip irrigation results in better partitioning of photosynthesis, higher yield and greater water use efficiency. Other advantage includes the use of saline water up to 8-10 dS/m without affecting the yield. In addition, fertilizers can also be combined and delivered simultaneously with irrigation water (drip-fertigation) more precisely to the root zone the efficiency of fertilizer use tremendously. It is also reported that lint yield of >2250 kg/ha was realized using drip irrigation at Arizona, U.S.A. Improvement in quality of cotton is also observed in relation to fiber fineness & maturity. 60% water can be saved using this method of irrigation.
V.Check Basin method:
In this method, field is divided in small plots surrounded by bunds on all four sides.Convenient check basin of square (2 m x 2 m to 4m x 4m) or rectangular size is used for irrigation. Here, accurate leveling is not necessary, since bunds are provided on all the four sides of the small basin. The water is kept within the basin and not allowed to run off. The size of ridges or bunds depends upon the depth of water to be impounded in the basin. The water is turned on to the upper side and is turned off following application of the required quantity of water. This method is more efficient in fine textured soil. Leaching of salts is also possible by impounding water and giving more opportunity time for infiltration. Yet, the drawback of this is the requirements for high degree of leveling for uniform distribution of water. However, for small streams, this method can be suitably adopted.
This is especially suitable to shallow sandy soils of uneven topography, where leveling is also not practicable, and to the regions where both labor and water is scarce. Sprinklers are advantageous compared to the surface methods as water can be delivered at a desired and controlled rate, thereby ensuring a uniform distribution of water and high (water use) efficiency. Although more extensively used in advanced countries, it is not popular in Nepal because of high initial investment cost. Today, sprinklers can be employed for any type of soil/crop except very fine texture soil. Sprinkler irrigation increases the concentration of soluble salts in upper zone of roots in heavy soils, so it is not considered as best for cotton field because cotton is sensitive to soluble salts.
Quality of Irrigation Water:
Use of inferior water with high sodium or total salt or both may cause deterioration to the physical properties of soil which ultimately influences the yield of cotton. Salt deposited from applied water tends to accumulate in the soil profile. Hence appropriate techniques are required for proper management of poor quality water. The quality of irrigation water is determined by following chemical characteristics:-
- Total concentration of soluble salts or salinity.
- Concentration of Sodium/ Sodocity.
- Concentration of bicarbonates and carbonate.
- Concentration of Boron, Fluorine that may be toxic to plant growth.
Management of saline water for irrigation:
Factors such as soil characteristics, plant types, climatic parameters and management practices are to be considered while using the saline water for irrigation.
- Lighter the texture, greater is the tolerance to saline water. So sprinkler irrigation holds best in light textured soils not in heavy soils.
- High organic matter content of the soil enhances the tolerance of crops to saline water used for irrigation.
- Furrow irrigation helps in solving the problems of soil salinity.
- Adequate irrigation is necessary to leach out salts away from the root zone which can be achieved by flooding the entire field.
Water Management in Irrigated Tract/ Management of water logged condition
Cotton requires equal attention for drainage, as for irrigation. Because it is sensitive to root aeration, no water stagnation should be allowed to occur. In cotton growing areas of Mid Western and Far Western terai, water stagnation occurs during the monsoons. The Opening of deep furrows after every 2 or 4 rows of cotton increases cotton yield.
Water logging greatly reduces response of cotton to fertilizers, leading to uneconomic yield. The major and immediate effect of water logging is blocking transfer of oxygen between the roots and the soil atmosphere. Plant roots may become so oxygen deficient that they cannot respire. As a consequence, root growth and absorption of nutrients is decreased leading to less overall plant growth. Water logging also tends to increase sodium uptake by cotton. During water logging, an enzyme that helps to exclude sodium from the plants is disabled, hence sodium can move into the root more freely. This may then affect the uptake of other nutrients and the growth of the plant. The availability of Nitrogen (N), Iron (Fe) and Zinc (Zn) decreases and Manganese (Mn) increased are directly affected by the decline in soil oxygen which is result of water logging, and uptake of N,K, P and Fe by the roots is also impaired.
Problems due to Excess Moisture
- Excess moisture at later stages delayed opening of bolls
- Bolls are susceptible to boll rot pathogens.
- Lodging of plants.
- Excess moisture generally has adverse effect on fiber quality, mainly because of increase in proportion of fibers that fall to mature properly.
Cotton is most important commercial crop, grown from very early of human civilization and has played significant role for the well being of mankind. Especially mid and far western terai areas of Nepal are famous for its cultivation. In Nepal it is mostly grown as rainfed crop. Wide variability exists between irrigated and non irrigated cotton. Chiefly furrow method of irrigation holds best for cotton because it saves water by 20-30% and also helps in reducing the concentration of soluble salts which lowers the production. Other methods such as drip irrigation, flooding, alternate furrow irrigation are also profitable for cotton field. Time and frequency of irrigation depends upon the variety, growing environment, climatic condition, soil moisture level. Cotton is most sensitive to water logging, so drainage is important as irrigation. Adoption of suitable packages of practices of water management can definitely uplift the cotton production.
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