Conservation Agriculture Effects on Soil Health, Weeds, and Productivity in a Maize–Sunflower System

This study investigates the impact of conservation agriculture (CA) and weed management (WM) practices on the productivity, profitability, soil health, and sustainability of a maize–sunflower cropping system. A strip plot design with 15 treatment combinations was employed, involving 5 tillage methods and three weed control strategies. Five treatments were imposed across kharif (maize) and rabi (sunflower): CT–CT, CT–ZT, ZTR–ZT, ZT–ZTR, and ZTR–ZTR, representing different combinations of conventional tillage, zero tillage, and residue retention practices. The ZTR–ZTR treatment combined with WM consistently achieved lower weed density and dry weight, alongside higher weed control efficiency (>70% at 45 DAS), resulting in significantly improved crop productivity and profitability. This combination also enhanced soil microbial populations (bacteria: 22.7 × 10 6 CFU/g, fungi: 17.2 × 10 4 CFU/g, actinomycetes: 29.5 × 10 5 CFU/g) and enzymatic activities (alkaline phosphatase, urease, and dehydrogenase). WM alone also improved microbial and enzymatic parameters compared to herbicide‐only and unweeded treatments. Herbicide dissipation (pendimethalin and atrazine) followed first‐order kinetics ( R 2 > 0.94), with >80% degradation observed within 30 and 45 days after herbicide application, respectively. These findings indicate that practicing zero tillage combined with residue retention and weed management enhances agroecosystem sustainability, improves soil biological health, and supports efficient and environmentally sound weed control in maize–sunflower systems.