Effect of density between intercropped sorghum and stylosanthes on biomass production and quality under varying NPK fertilizer application rates

Abstract

This field study was conducted to investigate the effect of spaced-row pattern and NPK fertilizer rates on productivity and quality of intercropped sorghum and Stylosanthes guianensis. Three spaced-row pattern (S1 = 90 × 20 cm, S2 = 75 × 25 cm, and S3 = 60 × 30 cm, respectively) and NPK fertilizer application rates (N1 = 0 without NPK, N2 = 100 kg/ha, N3 = 200 kg/ha, respectively) were investigated under two local sorghum varieties (V1 = var. Kawali and V2 = var. Super-2) in a 2 × 3 × 3 split–split-plot design. Intercropped sorghum × stylosanthes in S3 resulted in higher dry matter (DM) content and biomass production than that in S1. NPK fertilization significantly increased DM and organic matter (OM) production by 16.2–115.0% and 16.1–115.2%, respectively, compared to those without NPK fertilization. Interaction effects of V × NPK and V × S × NPK were detected that contributing to the increase in biomass and nutrient quality of the forages. In vitro DM and OM digestibility rates for V1-S were higher than at V2-S. In conclusion, V2 produced a higher biomass, whereas V1 was superior in terms of nutrient quality. Spaced-row at 60 × 30 cm and 100 kg/ha of NPK were efficient in improving the productivity and nutrient quality of sorghum and stylosanthes.