Intercropping and species interactions on physiological and light use characteristics of forage cereals-legumes combinations in semi-arid regions

Forage maize (Zea mays L.) and sorghum (Sorghum bicolor L.) are important forages for livestock production system across the world. Forage quality of them can be improved by intercropping with annual legumes. Field trials were conducted with an objective to evaluate their performance in dry matter, leaf area index (LAI), and light interception (LI) and radiation use efficiency (RUE) of maize, sorghum, lablab (Lablab purpureus L.), and lima bean (Phaseolus lunatus L.) grown in sole cropping or intercrops. A linear regression models were developed for the relationship between LAI and LI and between PAR and dry matter. Intercropping land use advantage was greater than that in any of the sole crops as indicated by land equivalent ratio (1.09–1.49). Maize grown as both sole and intercrop produced greater dry matter than brown midrib and brachytic dwarf sorghums. It was strongly associated with the LI. Both LAI and LI increased rapidly upto 60–70 days after planting and plateaued thereafter. Intercropping systems reached greater LAI, which intercepted 90% of the light, much earlier than any of the sole crops. Intercropping systems had greater RUE than in sole crops, but it was varied with season, crop, and year. Models indicated strong relationships between LAI and LI and between PAR and dry matter. Overall, lablab found superior to lima bean for intercropping with maize or sorghum for forage production.