Mixed Cropping of Dwarf Napiergrass (Pennisetum purpureum cv. Mott) with Indigofera (Indigofera zollingeriana) using an Alley Cropping System

Abstract

Background: Mixed cropping of forage grasses and legumes can potentially improve the performance of herbivores. However, the feasibility of grasses mixed-cropped with legumes should be examined at different plant densities. Aim: This study aimed to evaluate the growth characters and forage chemical composition in dwarf napiergrass (Pennisetum purpureum cv. Mott) with Indigofera (Indigofera zollingeriana) grown using alley cropping. Methods: Three densities of dwarf napiergrass with Indigofera, i.e., high density (2 and 1 plants m-2, respectively); medium density (1.33 and 1 plants m-2, respectively); and low density (1 and 1 plants m-2, respectively) were applied under rainfed conditions in Makassar. Results: Plant density significantly affected growth characteristics, such as plant height and tiller density in dwarf napiergrass (p<0.05), and non-significantly affected plant height and branch density (p>0.05) in Indigofera. Plant density did not affect the yielding ability at the first defoliation and annual total of yields (p>0.05), except at the second defoliation when the dry matter production of dwarf napiergrass peaked in the low plant density treatment (p<0.05). In terms of chemical composition, plant density significantly affected fiber concentrations of acid detergent fiber and neutral detergent fiber, which were lowest at low plant densities (p<0.05). The acid detergent lignin and cellulose concentrations tended to be lower at low plant densities, but the differences were not significant (p>0.05). Conclusion: We consider that alley cropping systems for dwarf napiergrass and Indigofera are suitable if low plant densities are employed in the region.