# Precision nitrogen and water management in double zero -till wheat: effects on photosynthetic parameters, productivity, nutrient-use efficiency and N2O emission

## TL;DR

This study shows that using zero-tillage with precise water and nitrogen management improves wheat growth, yield, and environmental outcomes in the Indo-Gangetic Plains.

## Contribution

The study introduces a double zero-tillage wheat system combined with precision irrigation and nitrogen strategies to enhance sustainability and productivity.

## Key findings

- Double zero-tillage wheat increased growth metrics and yield by up to 9.9% compared to conventional methods.
- Irrigating at 25% DASM boosted photosynthesis and grain yield by 18.3% and 9.23%, respectively.
- NE® + SPAD-based nitrogen management saved 40 kg N/ha while reducing N2O emissions significantly.

## Abstract

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.

Flowchart illustrating sustainable wheat farming practices. Conventional methods lead to soil and water degradation, threatening rice-wheat cropping. Double-zero tillage with HD-3086, irrigation at 50 percent DASM, and NE®+SPAD-based methods increase productivity, resource efficiency, reduce N₂O emissions, improve incomes, and enhance sustainability. Aligns with UN Sustainable Development Goals: zero hunger, clean water, responsible consumption, climate action, life below water, and life on land.