Mitigating moisture stress in Brassica juncea through deficit irrigation scheduling and hydrogel in ustocherpts soils of semi-arid India

A field experiment was conducted to study the effect of irrigation scheduling and use of superabsorbent polymers on growth, seed and water productivity, soil moisture dynamics in Indian mustard under semi-arid conditions. During the first year of the study, the increase in the mustard seed yield with irrigations applied at IW/CPE (Irrigation water, mm/Cumulative Pan Evaporation, mm (CPU) ratios 0.8, 0.6, 0.4 and no-irrigation (rainfed) with hydrogel application (+HG) was 18.6, 17.9, 14.4 and 28.3%, respectively, over no hydrogel (-HG). The seed yield enhancement by hydrogel application during the second year varied from 3% under sufficient irrigation to 24.9% under rainfed conditions. The pooled data indicated that the production indices and economics with hydrogel use improved significantly (P ≤ 0.05) under limited irrigation or rainfed condition. A net increase of 38, 27.7, and 10.7%, in production efficiency (PE), the net return, and profitability of mustard respectively was observed due to the use of hydrogel improved under the rainfed condition. Under limited irrigation (single irrigation at IW/CPE 0.4), a net increase of 24.2 and 31.8%, in the marginal and gross water productivity of mustard respectively, was recorded with hydrogel use. Similarly, in rainfed conditions, hydrogel increased gross water productivity by 22.6%. The energy intensity under irrigations scheduled at IW/CPE 0.8, 0.6, 0.4, and rainfed condition, was enhanced by 4.9, 5.9, 6.7, and 10.5%, respectively, due to hydrogel application. Thus, the use of hydrogel both under the rainfed condition and deficit irrigation has the potential to enhance productivity, profitability, and bio-energy output of Indian mustard in semi-arid agro-ecologies.