Agriculture uses as high as 85 percent of the available water in India of which the irrigated area accounts for nearly 48.8 percent of the 140 million hectare (mha) of agricultural land, while the remaining 51.2 percent is rainfed. Groundwater is the most common source of water used for irrigation in India. Of the 160 million ha of cultivated land, 39 million ha is irrigated by ground water, 22 million by irrigated canals and about two third of cultivation still depends on the monsoon.

India, a water stressed country

Over extraction of groundwater for irrigation coupled with changes in rainfall patterns and climate change are however turning India into a water stressed country. The per capita annual water availability in India has declined from 5,177 cubic metre (cm) in 1951 to 1,508 cm by 2014, and is likely to reduce further to 1,465 cm and 1,235 cm by 2025 and 2050, respectively.

Reducing consumption of water and maximising agricultural productivity are crucial to deal with increasing water stress in the country. One important concern in the context of water use is whether the water is used efficiently for different crops.

Irrigation and water use efficiency

Irrigation plays a very important role in increasing the crop output and helps farmers use better varieties and technologies which help to increase productivity. Irrigation has many advantages.

Cropping patterns followed in the irrigated area are much more superior to that of un-irrigated area and the crop output is higher under irrigated land. Irrigation helps farmers to use the available land more intensively throughout the year with higher level of cropping intensity, which is not possible under un-irrigated land. Also, the risk in getting the assured output from the crops cultivated due to moisture stress is very high in un-irrigated land as compared to irrigated land.

While a large number of studies have analysed the role of irrigation in agriculture, very few have focused on water use efficiency in crop cultivation. Thus, while farmers have been cultivating water-intensive crops using groundwater, very little information is avolable on whether the crops are being cultivated efficiently.

A study titled 'Water use efficiency in different crops cultivation: A study of borewell owning farmers from South India' published in the Journal of Critical Reviews evaluated the water use efficiency of three water-intensive crops namely curry banana, sugarcane and paddy among borewell owning farmers from Sivagangai block of Sivagangai district of Tamil Nadu. The study aimed at:
•    Analysing the operation-wise cost of cultivation in curry banana, sugarcane and paddy
•    Evaluating the productivity of curry banana, sugarcane and paddy
•    Calculating the water use efficiency of curry banana, sugarcane and paddy in relation to value of output and profit of the crops
•    Comparing the income and profitability of curry banana, sugarcane and paddy

The study found that:

Water consumption

The water use pattern of three different water guzzling crops were not the same. On an average, number of irrigation used per acre was more or less same for banana and sugarcane cultivation (44 and 47 respectively) as compared to paddy cultivation (12). But, hours used for each turnof irrigation were less different for these three selected crops. As a result of the number of irrigation used and application of each turn of irrigation, total hours of water used for per acre was much higher for curry banana cultivation, requiring 2300 HP hours of water as compared to sugarcane which was 1761 HP and 475 HP for paddy.

Operation-wise cost of cultivation

The operation-wise cost of cultivation was very high for seed and sowing, weeding and irrigation except harvesting and transportation. The total cost of cultivation for curry banana was Rs. 47644/acre, for sugarcane - Rs. 68231/acre and Rs. 26780/acre for the paddy cultivation. Among these three crops, sugarcane required a high cost of cultivation per acre as compared to curry banana and paddy.

Of the three, curry banana and sugarcane farmers incurred high costs on seed and sowing (23.38 percent and 15.43 percent respectively) as transplantation of these two crops is labour intensive as compared to paddy crop. Irrigation application in both curry banana and sugarcane was about 18.51 percent and 11.81 percent of its total cost of annual cultivation, but was low (9 percent) for paddy cultivation. Paddy farmers spent more on fertiliser (19.24 percent) as compared to other crops. The third highest share in total cost of cultivation was found to be for weeding and interculture operations which was about 13 percent for both banana and paddy and just seven percent for sugarcane.

Productivity

The study found that the productivity of sugarcane was high at 562 quintal per acreas compared to curry banana which was 186.65 quintal and paddy at 23.21 quintal per acre.

Irrigation water and economic productivity

The highest profits were found to be in curry banana cultivation, due to the less cost of cultivation as compared to sugarcane and high output with profit per acre estimated at Rs.218678 followed by sugarcane at Rs.80695. Paddy showed the least profit per acre at Rs.9320/acre per season of paddy cultivation.

Water use efficiency

The water use efficiency was high for sugarcane cultivation at 3.13 HP hours of water for producing one quintal of annual output.

The lowest water use efficiency was found to be in paddy crop, which consumed 20.47 HP hours of water for producing one quintal of per seasonal output while for curry banana, the water required to produce one quintal of output was 12.32 HP hours of water.

Paddy, the most inefficient crop

Among the three crops, highest cost of cultivation was found to be with sugarcane crop as compared to other two crops. The irrigation water productivity and water use efficiency was higher for sugarcane crop. But, in the case of profitability and economic water productivity, curry banana crop cultivation seemed to be more efficient.

Paddy was found to be the most inefficient crop of the three both in terms of irrigation water productivity and economic water productivity.

However, farmers still continue to cultivate paddy using conventional flooding methods. These are extremely unsuitable and can prove to be extremely unsustainable taking into consideration the growing water crisis in the country. Urgent efforts need to be made in the form of designing special programmes with attractive incentives to change the cropping pattern from paddy to other crops among farmers that can give increased water productivity as well as more returns for every drop of water, argues the study.

The study can be accessed here

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