Plant Growth-Promoting Bacteria and Crop Residue in Rice-Wheat System Cultivated with Favorable Tillage Influence Crop Productivity, Nutrient Uptake, Soil Quality, and Profitability in the Terai Agro-Ecological Zone of West Bengal, India

A field study was conducted from 2021 to 2023 in a rice-wheat cropping system in the Terai agro-ecological zone of West Bengal, India, using different management practices, i.e., tillage (conventional tillage, CT, and zero tillage, ZT), crop residue (R), and plant growth-promoting bacteria (B). This study was a part of long-term research on resource conservation technology (conservation agriculture, CA), undertaken on a research farm in Uttar Banga Krishi Viswavidyalaya, Pundibari (Cooch Behar), West Bengal. The project was established in 2006 in acidic alluvial soil. The aim of this study was to evaluate rice-wheat productivity, nutrient uptake, soil quality, and profitability after the 16th and 17th crop cycles under the above-mentioned management practices. The results revealed that the pooled yield of rice grain and straw was significantly higher under the CT + R + B treatment than under the other treatments (ZT, ZT + B, ZT + R, ZT + R + B, CT, CT + B, and CT + R). However, the wheat grain and straw yields were significantly greater under the ZT + R + B treatment than under other treatments. The system's grain yield and straw yield were significantly higher under the CT + R + B treatment, on par with ZT + R + B, compared to the other treatments. Nutrient uptake (nitrogen, N; phosphorus, P; and potassium, K) was increased by retaining R and inoculating B compared to the sample without R and without B. Soil properties, including organic carbon, available N, available P, and available K, were improved in all the treatments compared to the initial values, but the impact was greater in the treatments with R and B than in those without R and without B. In the 5-10-cm soil layer, the above-mentioned soil properties were also improved over the initial (2006) values by 37, 126, 65 and 60%, respectively, by applying the best treatment (ZT + R + B). In economic terms, the benefit-cost ratio was significantly higher under the CT + R + B treatment for rice crops (2.99) and ZT + R + B for wheat crops (3.37). Therefore, we can conclude that, after 17 years of cultivation, for rice, CT-based treatments performs better than ZT-based treatments; meanwhile, for wheat cultivation, ZT-based treatments produces greater yields than CT-based treatments in the Terai agro-ecological zone of West Bengal, India.