Assessing Legumes for Forage Sorghum Based Intercropping Systems in the Southern High Plains.

Resource use efficiency needs to be improved in forage production systems in the Southern High Plains to sustain the large dairy industry, where decreasing water resources are limiting the production of traditional forage crops such as corn or alfalfa. Intercropping legumes with forage sorghum offers an innovative way of increasing both quantity and quality of forage production in the region. However to develop a successful intercropping system, Legume crops must be identified that are well adapted to the region and fit well under the resource competition of an intercropping system. A trial was conducted at New Mexico State University Agricultural Science Centers at Clovis (Olton clay loam) and Tucumcari (Canez fine sandy loam) to evaluate 10 different legumes (e.g., lablab, cowpea, kidney bean, forage soybean, pigeonpea, favabean, yardlong bean, pole bean, lima bean and field pea) for sorghum based intercropping systems. Both erect growing and climbing legumes were included in the trial. Clovis received heavy rain and hail early in the season, which set back legumes more than sorghum. Tucumcari was the drier of the two locations and lack of sufficient irrigation water later in the season severely stressed all crops. Legume crop contribution to biomass was very low at Clovis due to an initial hail storm. At Tucumcari, a few legumes, including lablab cvs. Rongai and Rio Verde, cowpea cv. Ironclay, limabean cv. Willowleaf, showed promise. Canopy and leaf area index observations indicated early closure of canopy with intercropping. Total biomass production at both locations was not affected by intercropping; and monocrops of both sorghum and corn produced statistically similar biomass compared to intercropping systems tried. Further research is continued at Clovis in 2009.