Performance of Hyacinth Bean [Lablab Purpureus (L.)] in the Southern Great Plains.

Lablab is widely cultivated in parts of Africa, south and Central America, the Indian sub-continent and other regions of Asia. Though used as a grain crop, its potential as forage or green manure has been recognized in Brazil, Africa and Australia. While some cultivar development has occurred in southern Texas, there is no information available on the productivity and quality of lablab forage for the southern Great Plains. Experimental plots (3 by 20 m) were disked and fertilized with 60 kg ha^-1 P₂O₅ during middle of May 2007, and no N fertilizer was applied. Seeds of ‘Rongi’ lablab were treated with commercial inoculum and planted at 15 kg ha^-1 on May 22, 2007, in 40 cm spaced rows. Total biomass samples were collected at 5 sampling dates at 15-day intervals, beginning 45 days after seeding (July 9). Samples were oven-dried to determine biomass production, and nitrogen content and digestible dry matter were determined on samples. Biomass accumulation was slower the first three sampling dates (2026 to 8502 kg ha^-1; 99 kg ha^-1 d^-1 from 22 May to 15 Aug) while rate of accumulation was greater over the last three sampling dates (8502 and 22486 kg ha^-1; 194 kg ha^-1 d^-1 from 22 May to 14 Sep). Nitrogen concentration and digestible dry matter (DDM) were high during the first two sampling dates (29.69 g N kg^-1 and, 773 to 732 g DDM kg^-1). Forage quality declined slightly and was maintained during the last three sampling dates (25 g N kg^-1, and 698 to 708 g DDM kg^_1). Results suggest lablab can produce large amounts of high quality forage during the late summer and early fall in the southern Great Plains Region.