Soil moisture dynamics, rooting traits, crop and water productivity of wheat under different tillage, irrigation and nutrition conditions

Water scarcity coupled with reduced nutrient-use efficiency (NUE) is challenging the sustainability of wheat production in the North-Western Plains of India. Suitable soil tillage practices, water, and nutrient management are thus essential to harvest high wheat yields on a long-term basis. Thus, a fixed-plot experiment was set and continued for three years to assess the main and interaction effects of tillage, irrigation, and fertilizers on water-use efficiency (WUE) and wheat yield. Zero-till flat bed (ZTFB) and conventional till-raised bed (CTRB) condensed the irrigation water requirement by 1163–1218 m3 ha−1 and 698–762 m3 ha−1, respectively, compared to conventional till-flat bed (CTFB) without affecting wheat yields during 2016–2019. Apart from the saving in irrigation water, CTRB enhanced grain turn over by 8.12–31.5%, biomass by 3.47–34.1%, WUE by 27.0–30.9% and irrigation water productivity (IWP) by 55.2–57.5% over CTFB. Likewise, CTRB recorded a 4.4–10.1% greater photosynthetically active radiation (PAR) interception over CTFB and ZTFB during the study years. ZTFB had the highest moisture level (11.2%–22.5%) for 0–0.3 m soil layer. Applying irrigation at 25% depletion of available soil moisture (DASM) and 100% recommended rates of nutrients (RRN) resulted in significantly greater grain and biomass yields and WUE over the lower levels of irrigation and nutrients during 2016–2019. Further, the treatment combination of CTRB or ZTFB + 25% DASM +100% RRN was more productive, registering significant enhancements in grain and biomass yields, and WUE compared to CTFB with all other fertilizer and irrigation levels. The study concludes that 25% DASM with 100% RRN application under CTRB and ZTFB in wheat are synergic to attain higher crop and water productivity against individual application of these agronomic variables.