Growth of Introduced Temperate Legumes in the Edwards Plateau and South Texas Plains

Abstract

A study was conducted to evaluate production of 2 temperate, annual legumes at locations where temperature and moisture may seasonally place severe constraints on growth. Arrowleaf (Trifolium vesiculosum Savi) and subterranean (Trifolium subterraneum L.) clovers were grown at Beeville, in south Texas, and at Brady, 230 miles north of Beeville. Standing crop samples were collected at approximately 2-week intervals, starting 30 days post emergence and continuing to plant maturity during 2 years. Very little growth was made prior to 1 March at Brady in either year or at Beeville the first year. Total production was minimal (<1,500 kg/ha) at Brady. Arrowleaf produced about twice as much standing crop as subterranean at Beeville, 3,900 to 8,800 kg/ha (arrowleaf) versus 2,800 to 4,600 kg/ha (subterranean). No environmental variable showed a close association with growth rate when the data for 2 years and 2 species were included in simple correlations. In stepwise multiple regression equations, daily heat units was the most important variable followed by soil water. Early fall emergence and the development of a supraminimal canopy prior to the advent of growth-limiting winter temperatures had an overriding effect on winter growth as indicated by production differences in the 2 years at Beeville. The study shows that temperate annual clovers can be grown further west in the Southern region than current usage indicates.