In this essay we will discuss about irrigation practices adopted for growing pulses in India.
Essay Contents:
- Irrigation Practices for Growing Pigeonpea
- Irrigation Practices for Growing Chickpea
- Irrigation Practices for Growing Greengram and Blackgram
Essay # 1. Irrigation Practices for Growing Pigeonpea:
Among the pulse crops, kharif pigeonpea may be the only crop, which receives irrigation due to its longer duration, extending up to January – February (postrainy season). The other reason for irrigating the kharif sown crop is that it gives 2 or 3 flushes of crop harvests in 6 to 7 months.
On sandy soils of Morena, three irrigations (each 7.5 cm depth) at IW/CPE ratio of 0.9 resulted in seed yield of 2.0 t ha-1. However, at Rahuri, 10 irrigations (each 5 cm deep) scheduled at 0.75 ratio produced optimum yield of 4.34 t ha-1 from 3 flushes. At Navsari and Kota, optimum ratio was 0.6 requiring 2 and 4 irrigations respectively (Table 11.10).
In the absence of timely rainfall, one irrigation at flower initiation and another at pod development can double the yield of rainy season crop. Response to irrigation is, generally, more consistent in postrainy season crop on stored soil moisture. Three irrigations at monthly intervals can double the yield on light soils, while more than two may not be necessary for the crop on medium and deep soils during postrainy season.
TABLE 11.10: Seed yield of major pulses at optimum IW/CPE ratio
Suggested water management practices for pigeonpea crop during postrainy season are:
1. In the absence of adequate rainfall after October, one irrigation at flower initiation (second or third flush of flowering) and another at pod development can double the yield of kharif sown crop
2. Response to irrigation is, generally, more consistent in postrainy season crop on stored soil moisture. Three irrigations at monthly intervals can double the yield on light soils, while more than two may not be necessary for the crop on medium and deep soils during postrainy season
3. Scheduling irrigation at IW/CPE ratio of 0.75 during postrainy season may require two or three irrigations for optimum yield
4. If irrigation is scheduled based on DASM, 75 per cent depletion level requiring three irrigations could be adequate for optimum yield.
Essay # 2. Irrigation Practices for Growing Chickpea:
Around 60 per cent of the chickpea area in the country is rainfed, especially as a postrainy season crop on receeding soil moisture in black soils. The crop responds to irrigation on light soils of north India, particularly if winter rains are scanty. Even under drought conditions, more than two irrigations are not necessary. Where evaporative demand is high as in Peninsular India, irrigation can double the yield on relatively light soils.
However, under conditions of low evaporative demand as in north India, irrigation leads to excessive growth and lodging.
Branching, 45 days after seeding (DAS), and pod formation (75 DAS) are the critical stages for soil moisture stress.
Suggested irrigation management practices are:
1. If irrigation water is adequate, four irrigations (seeding, branching, flowering and pod filling) appears to be adequate for a crop on light soils. Generally, irrigation is not recommended for a crop on deep black cotton soils
2. Under condition of limited availability, two irrigations (branching and pod formation) can give economic yield on light soils
3. Scheduling irrigation at 0.5 IW/CPE ratio or at 75 per cent DASM, requiring 2 to 3 irrigations is equally effective as that of critical stages irrigation
4. Chickpea is very sensitive to soil salinity. Irrigation water with saline water that has 10 mmhos cm-1 can reduce the yield by 60 per cent.
Essay # 3. Irrigation Practices for Growing Greengram and Blackgram:
These two crops are grown as rainfed crops during rainy season. As such, they will not respond to irrigation unless there is prolonged dry spell at critical stages for soil moisture stress. Postrainy season crops grown with stored moisture on black cotton soils also will not receive any irrigation. These crops are grown as irrigated crops during summer in northern parts of the country and in winter in southern parts. In delta areas of south India, these crops are grown as relay crops with kharif rice without any irrigation.
Flowering and pod development stages are sensitive to soil moisture stress. In general, rainy season crop did not respond to irrigation at several places. Summer crop required 3 to 4 irrigations at IW/CPE ratio of 0.60 for normal yield at different locations.
Recommended irrigation practices are:
1. Under conditions of adequate irrigation facilities, four irrigations, one each at sowing, branching, flowering and pod development are adequate for optimum yield during winter and summer seasons
2. If irrigation water is limiting, a presowing irrigation followed by another irrigation at flowering can result in near optimum yield of winter and summer crops
3. Scheduling irrigation at 50 per cent DASM during flowering and pod formation and at 75 per cent DASM during other stages could be as effective as the above, at times of deficit water supplies
4. There may not be any necessity for irrigating these crops during rainy season unless prolonged dry spells occur during the critical stages for soil moisture stress.
Other pulse crops like cowpea, kidney bean and lentil are of little importance as irrigated crops. The principle of irrigating these crops is same as that for greengram and blackgram.