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

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.

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.

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.

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).

We consider that alley cropping systems for dwarf napiergrass and Indigofera are suitable if low plant densities are employed in the region.