Agronomic performance of soybeans in double-row soybean-maize intercropping systems under drought conditions in dryland areas

This study investigates the agronomic performance of high-protein soybean varieties under various double-row intercropping patterns in drought-affected dryland areas of Lombok, Indonesia. The research utilised an experimental approach using a split plot design. The main plot comprised four levels of double-row intercropping patterns (B): (B1) soybean sole cropping with a spacing of 40:20:15 cm, (B2) soybean-maize intercropping with a spacing of 70:20:15 cm, (B3) soybean-maize intercropping with a spacing of 60:20:15 cm, and (B4) soybean-maize intercropping with a spacing of 50:20:15 cm. The subplot included five high-protein soybean varieties (V): ‘Kemuning-1’ (V1), ‘Mutiara-2’ (V2), ‘Mutiara-3’ (V3), ‘Sugentan-2’ (V4), and ‘Gamasugen-2’ (V5). Each combination was replicated three times. The assessed agronomic traits included plant height, trifoliate leave number, node number, branch number, trifoliate leaf area, days to flowering, pod number, filled pod number, percent of unfilled pod, grain number, 100-grain mass, grain mass per plant, and grain yield per hectare. The results showed that the B×V interaction significantly influenced agronomic traits, including the number of nodes and branches, as well as yield and its components. The varieties ‘Kemuning-1’, ‘Mutiara-3’, and ‘Gamasugen-2’ produced better grain yields in sole cropping and double-row intercropping systems, but exhibited greater crop reductions under double- row intercropping, indicating lower adaptability to the system. In contrast, the consistent grain yield stability of ‘Mutiara-2’ and ‘Sugentan-2’ showed greater efficiency under double-row intercropping systems, indicating their superior adaptability to double-row intercropping conditions.