In this essay we will discuss about the irrigation practices used for growing crops.
Essay Contents:
- Essay on the Irrigation Practices Used for Growing Rice
- Essay on the Irrigation Practices Used for Growing Wheat
- Essay on the Irrigation Practices Used for Growing Maize
- Essay on the Irrigation Practices Used for Growing Sorghum
- Essay on the Irrigation Practices Used for Growing Groundnut
- Essay on the Irrigation Practices Used for Growing Sunflower
- Essay on the Irrigation Practices Used for Growing Soybean
- Essay on the Irrigation Practices Used for Growing Pulse Crops
- Essay on the Irrigation Practices Used for Growing Cotton
- Essay on the Irrigation Practices Used for Growing Sugarcane
- Essay on the Irrigation Practices Used for Growing Tobacco
- Essay on the Irrigation Practices Used for Growing Horticultural Crops
Essay # 1. Irrigation Practices Used for Growing Rice:
Irrigated (lowland) rice forms 45 per cent of the total area under rice. It is an inefficient user of water. Rice requires more water than other crops of similar duration due to huge water needs for puddling and land sub-mergence. About 50 to 70 per cent of applied water is lost by deep percolation.
The amount of water used at field is 20,000 m3 t-1 with poor water management and as low as 3,000 m3 t-1 with good management. Average production of grain (kg ha-mm-1 of water) is 3.7 for rice as against 13.4 for finger-millet, 12.6 for wheat, 9.0 for sorghum, 9.2 for maize and 8.0 for pearl-millet.
It is often said and agreed that seasonal water requirements for rice vary from 750 mm to 1,500 mm with the average being 1200 mm. If the irrigation period is assumed to be 120 days, the average requirement will be 10 mm day-1, which appears to be reasonable on condition that land submergence is the usual practice with a minimum of 2 mm day-1 percolation/ seepage losses.
Submergence vs Soil Saturation:
Land submerge is usually practiced due to associated major advantages of increase in availability of phosphorus, iron and manganese, reduction in losses of nitrogen under reduced soil conditions and less weed problem. Soil saturation minimises irrigation needs without appreciable decrease in yield, if the benefits of land submergence are taken care under saturated soil conditions.
Standing vs Flowing Water:
Standing water in lowland rice minimise the irrigation needs leading to high WUE. Flowing water from field to field increase grain yield by preventing accumulation of harmful salts in the soil. However, nitrogen losses will be higher with flowing irrigation water. Flowing irrigation is ideal for problem soils.
Intermittent Irrigation:
Land submergence during moisture sensitive periods and maintenance of soil saturation during other period can give comparable yields under conditions of low atmospheric evaporative demand. Irrigation needs can be brought down by 25 per cent. However, this practice leads to considerable loss in nitrogen.
Rotational Irrigation:
Required amount of water will be applied at regular intervals such that there may not be any standing water in the field between two irrigations. Irrigation interval is adjusted in such a way that the crop will not experience water deficits at any period. Rotational irrigation is usually practiced at times of deficit water supplies.
It ensures better equity among water users in command area. This method, however, leads to leaching loss of nitrogen besides heavy weed infestation. In practice, there may not be much saving in irrigation water as huge amounts are necessary to bring the soil to saturation at each irrigation.
Recommended irrigation Practices:
1. Land preparation in standing water (puddling) to minimise deep percolation losses.
2. Maintenance of 2 cm depth at transplanting, 5 cm upto 3 days after planting, 2 cm upto panicle initiation, 5 cm upto 21 days after flowering followed by gradual withholding of irrigations.
3. Mid-season drainage at late tillering for about 3 days in fertile heavy soils.
4. Draining the field before topdressing nitrogen fertilisers and allowing water after a day or two.
5. Maintenance of deep submergence at seedling and flowering periods and changing water periodically to dilute the salt concentration in saline soils.
Essay # 2. Irrigation Practices Used for Growing Wheat:
About 60 per cent of wheat is grown under irrigation. In favourable humid climate, about 1,000 m3 of water is needed to produce 1.0 t of wheat. About half of this is used in transpiration and the other half is lost by evaporation and unavoidable deep percolation.
Under less favourable conditions, about 5,000 m3 water is needed to produce 1.0 t of wheat. The crop is sensitive to water deficit at crown root initiation, flowering and grain formation periods.
Recommended water management practices are:
1. Pre-sowing irrigation for seed germination and stand establishment.
2. Scheduling irrigation at 25 per cent DASM or IW/CPE ratio of 0.8 to 1.0 with 6 to 8 cm depth of water, if water supply is adequate.
3. At times of deficit water supply, restricting the above schedule to moisture sensitive periods and scheduling irrigation at 50 to 60 per cent DASM or at IW/CPE ratio of 0.6 during other period.
4. Border or check basin surface irrigation method without water stagnation for long period.
5. High frequency irrigation with small depths at each irrigation using sprinkler system.
Essay # 3. Irrigation Practices Used for Growing Maize:
Maize is an efficient user of water in terms of total dry matter production. Potentially, it is the highest yielding grain crop among cereals. Although, roots may reach a depth of about 2 m in deep soils, effective root zone is confined to upper 80 to 100 cm. It is relatively tolerant to water deficits during vegetative and ripening periods. It neither tolerates severe drought nor waterlogging, particularly during flowering and grain development.
Recommended water management practices are:
1. Pre-sowing or post-sowing irrigation for seed germination and stand establishment.
2. Irrigations at 50 to 60 per cent DASM or at an IW/CPE ratio of 0.6 to 0.8 upto flower initiation and at 30 to 40 DASM during flowering (tasseling and silking) and grain development periods followed by at 75 per cent DASM during ripening period for higher WUE.
3. At times of deficit water supplies, irrigation can be scheduled at 50 per cent DASM during flowering and grain development and at 75 to 80 per cent DASM during rest of the period.
4. Furrow irrigation which enables draining of excess water, if any with plants on ridges is ideal for maize.
Essay # 4. Irrigation Practices Used for Growing Sorghum:
Sorghum crops are grown as irrigated crops in south India during rabi and summer seasons. Though, they are drought resistant, they respond well to irrigation. Sorghum and pearl-millet are sensitive to waterlogging during establishment period. Finger-millet and pearl-millet are usually transplanted in standing water with seedlings of about 20-25 days old.
Recommended irrigation practices are:
1. Pre-sowing or post sowing irrigation for better germination and stand establishment of sorghum.
2. Standing water for transplanting finger-millet and pearl-millet seedlings followed by a light irrigation 4-6 days after planting for seedling establishment.
3. At times of adequate water supply, these crops can be irrigated at 25 to 50 per cent DASM although the season.
4. At times of deficit water supply, irrigation can be scheduled at 50 per cent DASM during flowering and grain development periods and at 75 to 80 per cent during other periods.
5. Furrow irrigation is ideal for sorghum and pearl-millet crops, as it eliminates the danger of water stagnation at sensitive establishment period. Border or check basin irrigation can be used for finger-millet.
6. Since these crops can withstand drought, when water supply is limited, it is advantageous to use the available water over a large area for higher overall production, relative to the volume of water applied.
Essay # 5. Irrigation Practices Used for Growing Groundnut:
Groundnut is an irrigated crop during rabi and to certain extent in summer season. Though, the root system extends to about 1.75 m depth, major part of the system is confined to top 60 cm. Flowering, peg penetration and pod development periods are sensitive to water deficit.
Recommended irrigation practices are:
1. Pre-sowing irrigation for seed germination and better stand establishment.
2. Irrigation is usually not necessary upto three weeks after sowing.
3. Since flowering, peg penetration and pod development almost overlaps, it is essential to schedule irrigation at 25 per cent DASM during this period followed by at 50 per cent DASM during kernel development. An IW/CPE ratio of 0.8 to 1.0 is ideal throughout the reproductive period.
4. At times of deficit water supply, irrigation can be scheduled at 50 per cent DASM from flowering to pod development followed by 75 to 85 per cent DASM during kernel development period.
5. Six irrigations, one each at 25, 35, 45, 55, 70 and 90 days after sowing, in addition to pre-sowing irrigation results in high pod yield and high WUE on sandy loam soils.
6. Border or check basin irrigation is ideal. Keeping the total quantity of irrigation water applied constant, high frequency irrigation using sprinkler system gives higher pod yield and high WUE.
Essay # 6. Irrigation Practices Used for Growing Sunflower:
Sunflower is an irrigated crop during rabi and summer seasons. It can withstand short periods of severe soil moisture stress because of deep root system extending upto about 3 m soil depth.
It utilises 50 to 60 per cent of its total water requirement during flowering period. Adequate soil moisture is necessary during late vegetative period for bud development. Flowering period is most sensitive to water deficit.
Recommended irrigation practices are:
1. Pre-sowing irrigation for better germination and stand establishment.
2. Scheduling irrigation at 25 per cent DASM or at an IW/CPE ratio of 0.8 to 1.0 throughout the growth period is ideal for high yield.
3. At times of deficit water supply, irrigation can be scheduled at 40 per cent DASM during late vegetative (bud development) and flowering periods and at 75-80 per cent DASM during rest of the growth period for high WUE.
4. Furrow irrigation which avoids water stagnation in the field is best suited because of sensitivity of this crop for water-logging.
Essay # 7. Irrigation Practices Used for Growing Soybean:
This crop has well developed tap root system extending up to 1.5 m soil depth. Most rapid root growth is often noticed after the start of flowering. At germination, the available soil moisture content should not exceed 85 per cent or fall below 50 per cent.
Recommended water management practices are:
1. Light pre-sowing irrigation for optimum seed germination.
2. At other stages, irrigations can be scheduled at 30-40 per cent DASM or at an IW/CPE ratio of 0.8 for high seed yield.
3. At times of deficit water supply, irrigation may be scheduled at 40 per cent DASM during late flowering (appearance of small pods) and initial pod filling and at 75-80 per cent during other growth periods.
4. Furrow or check basin irrigation is well suited for the crop.
Essay # 8. Irrigation Practices Used for Growing Pulse Crops:
Red-gram (pigeon-pea), green-gram and black-gram are irrigated crops during rain and summer seasons. Red-gram, though, resistant to drought, responds well to irrigation. Green-gram and black-gram are cultivated in south India only when the available water supply is not adequate for rice, vegetable crops, groundnut and finger-millet.
If water is available for about four months (8-10 irrigations) groundnut or finger-millet are the usual crops. Sunflower is the next choice if water is available for 3 months (4-6 irrigations). Green-gram and black-gram can be cultivated even if water is adequate only for 3 irrigations.
Recommended irrigation practices are:
1. If irrigation water is not limiting, irrigation can be scheduled at 50 per cent DASM during flowering and pod filling periods and at 80 per cent DASM other periods.
2. All the three crops need a minimum of one pre-sowing irrigation, one at flowering and another at pod filling period for economic returns.
3. All the three crops can be irrigated by border or check basin method.
Essay # 9. Irrigation Practices Used for Growing Cotton:
Waterlogging greatly reduces response of cotton to fertilisers leading to uneconomic yield. Adequate water supply is needed for good budding and fruiting. Excess irrigation water early in the growing period will restrict root and crop development. Cotton requires adequate water, particularly, just prior and during bud formation.
Continued water supply during flower opening and boll development periods results in prolonged and excessive growth. Abrupt changes in water supply will adversely affect growth and cause flower and boll shedding. Severe water deficits during flowering may fully half growth, but with subsequent water supply crop growth recovers and flower production is resumed.
Recommended water management practices are:
1. 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.
2. Irrigation at 60 per cent DASM is adequate during vegetative period.
3. At flowering, irrigation may be scheduled at 75 per cent DASM to check vegetative, growth without impairing yield. However, delayed irrigation during this period leads to considerable flower and bud shedding.
4. Irrigation at 75 per cent DASM is adequate during boll development and ripening since the root system can absorb moisture from deep soil profile.
5. Irrigations can be terminated 4 to 5 weeks before final pickings.
6. Furrow irrigation, which allows prevention of water-logging is the most ideal method of irrigation. However, drip irrigation is gaining importance in areas of inadequate irrigation water availability.
Essay # 10. Irrigation Practices Used for Growing Sugarcane:
Adequate available moisture throughout the growing period is important for high yield, because vegetative growth including cane growth is directly proportional to the water used by the crop. Frequency and depth of irrigation should vary with growth periods of the cane. Frequent light irrigations seems to be better than heavy ones at long intervals.
Recommended irrigation practices are:
1. During seedling emergence and establishment, light frequent irrigations are preferred. Irrigation at 30 per cent DASM is optimum.
2. Tillering is proportional to the frequency of irrigation during formative phase. As such the above irrigation schedule appears to be optimum.
3. There is close relationship between stem elongation and water use during grand growth period. Irrigation interval can be extended but depth of water application should be increased. Irrigations can be scheduled at 50 per cent DASM during this period. About 85 per cent leaf sheath moisture has to be maintained.
4. During maturity period, irrigation intervals should be extended to bring the crop to maturity by reducing the rate of vegetative growth. Irrigation can be scheduled at 80 per cent DASM during this period.
5. Irrigation can be stopped when the crop reaches arrowing (flowering) to increase sucrose accumulation.
6. Commonly used furrow irrigation is very effective. Sprinkler and drip irrigations have been successfully used, particularly in Hawai.
Essay # 11. Irrigation Practices Used for Growing Tobacco:
Tobacco should not be irrigated with water containing more than 40 ppm chloride because of its deleterious influence on quality. Irrigation often reduces nitrogen and nicotine content and increases sugar content of leaves. Fluecured tobacco in black soils need only one irrigation at 40 to 50 days after planting. On light soils, however, it responds well to timely irrigation.
Recommended irrigation practices are:
1. During first 4 weeks after emergence in the seedbed, the seedlings require 4 l m-2 day-1. From 30 days till transplanting the seedlings should receive lesser water to obtain robust seedlings.
2. A light irrigation is necessary for quick establishment of the planting seedlings followed by an irrigation after 20 days.
3. Irrigation is necessary at knee height stage for increasing number of leaves per plant and their size.
4. Scheduling irrigation at 50-60 per cent DASM between knee height and topping stages is ideal for optimum leaf weight and chemical composition.
5. One or two light irrigations (40 mm depth) at 80 per cent DASM appears to be appropriate during ripening period for optimum yield and quality.
6. Check basin or furrow irrigation without water stagnation is ideal for tobacco.
Essay # 12. Irrigation Practices Used for Growing Horticultural Crops:
a. Cabbage:
Cabbage has an extensive shallow root system. Majority of the root system is confined to top 50 cm of the soil profile. It is characterised by slow growth during first half of the growing period. During the following periods, the plant doubles its weight in every 10 days over a total period of about 40 days. Response to irrigation increases with development of the crop.
Recommended irrigation practices are:
1. During the slow developmental vegetative period, the crop is little affected by water deficits. As such irrigations can be scheduled at 50 per cent DASM in the upper 40 cm soil depth.
2. Water deficits during head formation and enlargement cause severe reduction in yield. Irrigation should be scheduled at 25 per cent DASM during this period.
3. At times of deficit water supply, water savings can be made during first half of the growing season with irrigation schedules at 75 per cent DASM.
4. Border, check basin or furrow irrigation can be followed. Sprinkler and drip irrigation are also gaining importance in places of irrigation water scarcity.
b. Cauliflower:
As the root system is confined to 50 to 60 cm soil profile, frequent irrigations are necessary throughout the crop period. Stagnation of water at any stage leads to physiological disorders. Irrigation should be scheduled at 25 per cent DASM in the 30 cm soil depth.
At times of deficit water supply, scheduling irrigation at 50 per cent DASM leads to high WUE. In general, 3-4 irrigations are required depending on winter rainfall. Any surface method of irrigation is equally effective for cauliflower.
c. Onion:
Onion, along with most vegetable crops is sensitive to water deficit. When the soil is kept relatively wet, root growth is reduced favouring bulb enlargement. The crop is most sensitive to water deficit during the period of rapid growth (60 days after transplanting). It is equally sensitive during transplantation. For a seed crop, flowering period is very sensitive to water deficit.
Recommended water management practices are:
1. Irrigation can be scheduled at 40 per cent DASM during vegetative growth period.
2. The crop should be irrigated at 25 per cent DASM in the top 30 cm soil depth till it reaches maturity.
3. Irrigation should be discontinued as the crop approaches maturity (20 days before harvest), to allow tops to desiccate and prevent second flush of root growth.
4. Furrow irrigation is ideal for onion crop.
d. Potato:
Potato is relatively sensitive to water deficits. To optimise the yield, soil should be maintained at relatively high moisture content. Irrigation schedule should be based on avoiding water deficit during the periods of stolonisation and tuber initiation and tuber enlargement. Irrigation can be restricted during early vegetative and ripening periods.
Recommended irrigation practices are:
1. Irrigation can be scheduled at 50 per cent DASM during early vegetative period. An IW/CPE ratio of 0.75 is equally good during early period.
2. Since water deficit during stolonisation and tuber enlargement have the greatest adverse effect on yield, irrigation should be given at 25 per cent DASM or at an IW/CPE ratio 0.9 to 1.0.
3. At times of inadequate water supply, water can be saved by irrigating the crop at 60 per cent DASM during early vegetative period and at 75 per cent DASM during ripening period.
4. Furrow irrigation is an ideal irrigation method for potato.
e. Tomato:
This crop has fairly deep root system extending upto 1.5 m soil depth. Maximum root depth is reached by 60 days after transplanting. In general, a prolonged severe water deficit limits growth and yield which cannot be corrected by heavy watering during later period.
Highest demand for water is during flowering. However, withholding irrigation during this period is sometimes recommended to force less mature plants to flower for uniform flowering and ripening.
Recommended irrigation practices are:
1. Since the plant is sensitive to excess moisture during seedling stage, irrigation can be scheduled at 50 per cent DASM at this period.
2. Water supply during flowering and fruit set must be at 40 per cent DASM with light and frequent irrigations.
3. Heavy, irregular irrigations or dry periods alternating with wet periods should be avoided.
4. At times of deficit water supply, irrigation can be concentrated during flowering and fruit development.
5. Furrow method of irrigation is well suited for tomato. Drip irrigation has gained popularity in the recent past.
f. Citrus:
As a perennial crop, its response to water supply at a particular period depends on the level of water supply prior to that period during the same season and also on the level of water supply during previous growing season.
Citrus is sensitive to excess moisture. Water-logging predisposes the plant to fungal diseases. It is also sensitive to salinity. Irrigation water should not have more the 4SAR, 140 ppm chlorine, 0.5 ppm boron and 2000 ppm total soluble salts.
Irrigation can be scheduled at 50 per cent DASM in 30 cm of top soil. At times of water shortage, irrigation can be scheduled at 75 per cent DASM. Young trees upto 6 months require light irrigation at 4 to 5 days interval. From 6 to 12 months, weekly irrigation is optimum.
From one year upto bearing, irrigation can be given at 10 days interval. For fruit bearing trees, irrigation is necessary at 10 days interval in rainy season, 12 days in winter and 7 days in summer. Most common method of irrigation is basin method. Drip irrigation is most effective in minimising irrigation need of citrus.
g. Banana:
Banana is very sensitive to salinity and water-logging. It requires frequent irrigations throughout the crop period. Establishment and early vegetative periods determine the potential for growth and fruiting. As such adequate water supply is essential during this period.
Water deficit during flowering limit leaf growth and number of fruits. Water stress during fruit growth affect both fruit size and quality. Scheduling irrigation at 30 per cent DASM at any stage is optimum. Furrow irrigation is ideal for banana.
h. Grape:
Grape, a perennial crop, can adjust to a certain extent to limited water supply by developing deep root system. For optimum yield in the same year and following years, good vegetative growth during vegetative period is important.
Water deficit should not occur at rapid lateral shoot growth. The soil water content should be at field capacity at the end of winter to ensure adequate supply during first month of growing period. Shoot elongation is very sensitive to water deficits.
Prior and during flowering, adequate water supply is necessary for flower development. Water deficits at this period retard flower development, while severe deficit reduces fruit set. Fruit enlargement depends on a steady, continuous water supply. This period is, however, less sensitive to water deficits than during shoot growth.
Severe water deficit at fruit growth and ripening causes shriveling of fruits. Severe water deficit during ripening delays maturity and allows sun-burn. The berries develop dull colour. After the harvest of fruits, there is no necessity for irrigation. If dry spell is prolonged, one or two irrigations may be given during summer months.