Assessment of Yield Gap and Factors Causing Yield Gap in Rapeseed-Mustard in Assam, India

Abstract

Rapeseed-mustard constitutes a major oilseed crop in Assam; however, its on-farm productivity continues to lag behind the attainable yield levels. The present study was conducted in Undivided Sonitpur and Lakhimpur districts of Assam with the objective of analysing the magnitude of the yield gap and identifying the factors contributing to this gap across different farm size groups. A multi-stage purposive-cum-random sampling procedure was employed to select 120 farmers, who were stratified into four farm size groups as marginal (below 1.00 ha), small (1.01-2.00 ha), semi-medium (2.01-4.00 ha) and medium (4.01 ha & above). The data were analyzed using the International Rice Research Institute (IRRI) yield gap method to estimate the magnitude of the yield gap and multiple regression models to identify the contributing factors. The results revealed substantial differences between potential, demonstration, and actual yields. The Total Yield Gap (TYG) was highest on marginal farms (5.99 q/ha) and lowest on medium farms (4.93 q/ha), indicating that the gap tends to decrease with increasing farm size. The yield gap of rapeseed-mustard was found to be higher in the Undivided Sonitpur district than Lakhimpur district. On average, sample farmers realized only 72.76 per cent of the potential farm yield, suggesting considerable scope for improving productivity. Regression results showed that type of seed (T1), muriate of potash (MOP), Technology Adoption Index (TAI), and contact with extension personnel (CEP) had a significant and negative influence on Yield Gap-II, affirming their critical role in bridging the productivity gap. Conversely, variables such as seed rate, tillage, fertilizer application, education, experience, access to credit, and district differences did not exhibit any significant impact. The study highlights the need for strengthening extension services, ensuring timely input supply, and promoting improved technologies to enhance productivity and reduce the yield gap in rapeseed-mustard cultivation in Assam.