Conservation Agriculture- Based Planting Techniques and Weed Management Practices Influence on Nutrient Content and Their Uptake in Dry Direct-Seeded Rice (Oryza sativa L.)

Abstract

Conventionally established rice leads to major challenges in crop production like soil health degradation, water table declination and labour scarcity which ultimately increases the cost of production. To address these issues of transplanted rice, different conservation agriculture (CA) based crop establishment practices in combination with suitable weed management options were incorporated to sustain rice productivity. The field trial was conducted for two years during kharif season of 2018 and 2019 at Research Farm, Banaras Hindu University, Varanasi, Uttar Pradesh (India). The experiment was laid out in split plot design having four planting techniques in main plots viz., farmer’s practice (Conventional Transplanting), zero-till direct seeded rice (ZT-DSR), reduced-till direct seeded rice (RT-DSR) (Rotavator single pass) and conventional-till direct seeded rice (CT-DSR) and five weed management practices viz., pendimethalin 1 kg ha-1 pre-emergence (PE) followed by (fb) chlorimuron + metsulfuron (4g + 4g ha-1) at 20 days after sowing (DAS), pendimethalin 1 kg ha-1 PE fb pyrazosulfuron (30 g ha-1) at 20 DAS, bispyribac-sodium + chlorimuron + metsulfuron (25g + 4g  + 4g ha-1) at 20 DAS, hand weeding at 20 and 40 DAS and Weedy check in sub-plots and replicated thrice. The results showed that Nitrogen (N), Phosphorus (P) and Potassium (K) content in grain and straw were not significantly influenced by planting techniques and weed management practices. However, among various crop establishment methods CT-DSR recorded significantly higher N, P and K uptake by both grain and straw over rest of the treatments except ZT-DSR during both the years.  Similarly, two hands weeding (at 20 DAS and 40 DAS) recorded the highest N, P and K uptake by the crop. With respect to herbicidal treatments, higher N, P and K uptake by crop was found with the application of pendimethalin 1 kg ha-1 (pre-em) fb  chlorimuron + metsulfuron (4g + 4g ha-1) at 20 DAS compared to others during both the years of experimentation. Based on the results, it is concluded that application of pendimethalin 1 kg ha-1 PE fb chlorimuron + metsulfuron (4g + 4g ha-1) at 20 DAS to CT-DSR was registered maximum N, P and K uptake by both grain and straw of rice.