Sugarcane productivity in the semi-arid regions of Karnataka is increasingly constrained by water scarcity, necessitating efficient cropping strategies to enhance resource use and farm income. A field experiment was conducted at KJ Somaiya Institute of Applied Agricultural Research, Sameerwadi, Karnataka, to evaluate the performance of sugarcane-based intercropping systems under different row spacings and to assess competitive interactions using various indices. The experiment comprised sugarcane planted at 1.2, 2.4 and 3.6 m spacings intercropped with soybean, green pea and drill sown onion. The results revealed that competition indices such as competition ratio (CR) and aggressivity (A) varied significantly among intercrops, with soybean exhibiting higher competitiveness against sugarcane, particularly during early growth stages. Land equivalent ratio (LER) values greater than unity in all intercropping systems indicated superior land use efficiency over sole cropping, with the highest LER (2.10) recorded in sugarcane + green pea at 3.6 m spacing. However, area time equivalent ratio (ATER) values were comparatively lower, suggesting overestimation by LER due to differences in crop duration. Drill sown onion emerged as the most productive and economically viable intercrop, recording the highest sugarcane equivalent yield (204 tonnes/ha) and relative production efficiency (156.25 %). Although intercrop yields were lower than sole crops due to competition, intercropping systems significantly improved overall productivity and resource use efficiency. The study highlights that sugarcane planted at wider spacings with suitable intercrops, particularly onion, can enhance system productivity and profitability in water-limited environments.
Nadiger et al. (Thu,) studied this question.