Increasing crop diversity and yield of black rice through intercropping with mungbean at different row proportions on raised-beds

Additive intercropping with legume crops such as soybean, peanut and mungbean was reported to increase growth and yield of red rice grown on raised-beds under aerobic irrigation systems. This study aimed to examine the effects of row proportions of rice-mungbean on growth, yield and land equivalent ratio (LER) of black rice in intercropping with mungbean grown on raised-beds under replacement series. The experiment was conducted in Beleke, West Lombok, Indonesia, from November 2018 to March 2019, which was designed according to Randomized Complete Block Design testing four treatments (RM-1:0= rice monocrop; RM-2:1= rice-mungbean 2:1 rows, RM-2:2= 2:2 rows, and RM-1:2= 1:2 rows). To measure LER, monocropped mungbean was also planted in each block. All crops were planted under 20x20 cm plant spacing. The results indicated that row proportions of rice-mungbean significantly affected numbers of green leaves, tillers, panicles and filled grains per clump, panicle length, grain yield and dry straw weight per clump, and total LER, which were higher on black rice intercropped with higher proportions of mungbean (RM-2:2 and RM-1:2) than on monocropped black rice. Black rice grain yield per clump tended to be highest in RM-1:2 but total LER was significantly highest (1.27 or 127%) in RM-2:2.