Impact of nutrient management and zero-till crop establishment on rapeseed performance in rice-fallow ecosystems: Evidence from CFLDs in Manipur

Abstract

Rapeseed is a key winter oilseed crop well suited to rice-fallow ecosystems, where residual moisture after paddy harvest supports its cultivation with minimal inputs. In Manipur, productivity remains low due to conventional practices such as untimely broadcasting, use of local varieties, higher seed rates, absence of seed treatment, imbalanced fertilization, and poor weed and pest management. To demonstrate the advantages of improved cultivation practices, Cluster Frontline Demonstrations (CFLDs) were implemented from 2018 to 2024 across major rice-fallow villages of Bishnupur, Moirang, and Nambol blocks. The demonstrations showcased improved varieties (NRCHB-101, M-27, and TS-38), optimum seed rate (8 kg/ha), seed treatment, balanced nutrient application (40:20:20 NPK kg/ha), timely weeding, and IPM practices over farmers’ traditional methods. Across the study period, demonstration plots achieved 22.8-46.5% higher seed yield compared to farmers’ practice, with mean yields of 886.6 kg/ha against 758.2 kg/ha in farmers’ fields. Improved practices also enhanced profitability, recording a higher average net return (₹53,303/ha) and B:C ratio (2.51) than farmers’ practice (2.40). The mean technology gap (393.4 kg/ha), extension gap (128.4 kg/ha), and technology index (30.3%) indicated scope for further adoption and refinement. Overall, the results confirm that improved rapeseed production technologies are well suited to rice-fallow conditions, significantly improving productivity, resource-use efficiency, and farm profitability while strengthening technology dissemination among farmers.