Estimation of irrigation water requirement of soybean crop using remote sensing and gis

The paper focuses on analyzing the crop water requirement of soybean crop during the monsoon period on 10-daily basis for all sub-basins of Bearma basin have been computed by using CROPWAT model in Sagar and Damoh districts of Bundelkhand region in Madhya Pradesh, which is regularly suffered from frequent droughts due to large variation of rainfall. Irrigation demands of all users namely WU1, WU2, WU3, WU4, WU5, WU6 and WU7 in various sub-basins have been computed considering the command area in each sub-basin. The total command area of each user WU1, WU2, WU3, WU4, WU5, WU6 and WU7 is 284.19 km², 54.31 km², 121.26 km², 121.16 km², 356.13 km², 25.95 km² and 707.91 km² in SW1, SW2, SW3, SW4, SW5, SW6 and SW7 sub-basin, respectively. Area under soybean cultivation has been determined using supervised classification techniques with maximum likelihood algorithm were used for the land use classification in ILWIS 3.6. The maximum agricultural area lies in sub basin SW7 (707.91 km²), followed by SW5 (356.13 km²) and SW1 (284.19 km²). It is concluded that user WU7 required more irrigation water, 37.53 m³/sec between 10 August to 20 August followed by WU5 (18.51 m³/sec from 10 September to 20 September) and WU1 (13.91 m³/sec between 20 August to 31 August) whereas WU7 also shows maximum irrigation water requirement of 239.17 m³/sec followed by WU5 and WU1 as 54.78 m³/sec and 70.06 m³/sec during crop growing period of soybean crop. Therefore, it is immediate required that planning for drought mitigation can be carried out by constructing small size reservoirs in all sub-basins especially in sub-basin SW7, SW5 and SW1 to cater the water demands of all users by supplying more frequently irrigation water to fulfil the irrigation water requirement in the basin.