Biomass production and nitrogen accumulation of velvet beans, sunnhemp and pillipesara as influenced by plant density and phosphorus application.

摘要

Field experiments were conducted at Tamil Nadu Agricultural University during the northeast monsoon (NEM) season of 1993-94 and southwest monsoon (SWM) season of 1994 to study the effect of different spacings and phosphorus application on biomass production and nitrogen (N) accumulation of three green manure crops, pillipesara [Vigna aconitifolia], sunnhemp (Crotalaria juncea) and velvet beans (Stizolobium deeringianum [Mucuna deeringiana]). Velvet beans produced the highest biomass of 27.6 t/ha inthe SWM season followed by sunnhemp and pillipesara. Biomass production and N accumulation were higher at closer spacing (30X20 cm). Application of 50 kg P2O5/ha significantly increased the growth of all the three crops. Interaction between spacing andP levels was significant and highest biomass (10.0, 11.2 and 35.9 t/ha for pillipesara, sunnhemp and velvet beans respectively) was achieved in the treatment combination of 50 kg P2O5/ha and closer spacing (30X20 cm). Velvet beans and sunnhemp produced higher biomass in SWM season (27.6 and 10.1 t/ha) while NEM season was more favourable for pillipesara (8.5 t/ha).