Precision nitrogen and water management in double zero -till wheat: effects on photosynthetic parameters,...

Conventional tillage (CT), excessive irrigation, and indiscriminate nitrogen (N) use in wheat farming degrade soil and water resources in the Indo-Gangetic Plains (IGP), threatening the sustainability of the rice-wheat cropping system.

A two-year study (2019-21) in north-west IGP was conducted to assess the integration of zero-tillage (ZT) with precision water and N management for sustainability, nutrient efficiency, and environmental performance.

The study tested two crop establishment methods (ZT-wheat and double ZT-wheat) and three irrigation regimes-25%, 50%, and 75% depletion of available soil moisture (DASM), with silicon applied at 75% DASM-alongside three N strategies: 100% recommended N dose (RDN), NutrientExpert^® (NE^®) + Leaf Color Chart (LCC), and NE^® + SPAD-based N management, using a split-plot design.

Double ZT-wheat performed better over conventional ZT, showed superior growth (higher dry matter accumulation, leaf area index, and photosynthetic rate), 3.5% greater interception of photosynthetically active radiation (PAR), and 6.7-9.9% increases in grain/straw yields, and resource-use efficiency. Irrigation at 25% DASM increased photosynthetic activity, intercepted 18.3% more PAR, and yielded 9.23% higher grain over 50% DASM, though delaying irrigation to 50% DASM conserved water without significant yield loss. NE^® + SPAD-based N management saved 40 kg N ha^-1 while enhancing productivity and efficiency, and combining ZT with 75% DASM + silicon and NE^® + LCC significantly reduced N₂O emissions, thus suggested for implementation in the wheat growing regions.

The current study findings promote precision N-water strategies, and double ZT to enhance productivity, resource conservation, and environmental sustainability in the IGP's wheat systems addressing important sustainable development goals concerning agriculture.