Soil conservation benefits of large biomass soybean (LBS) for increasing crop residue cover

Soybeans are planted on approximately eight million hectares (20 M acres) of highly erodible land (HEL) in the United States. Soybean crops have been recognized as deficient in supplying crop residues that reduce soil erosion. A new type of soybean tested at the Beltsville Agricultural Research Center, Maryland, can grow to heights of 1.8-meters (6 ft) or more. The development of the large biomass soybean (LBS) suggested the potential of increased crop residue production to reduce soil loss on erodible soybean lands. An evaluation was conducted of the soil conservation benefits of LBS versus conventional soybean using data from a three-year field experiment. LBS produced more crop residue dry biomass and provided a mean increase of 31 percent more crop residue cover in the spring before mulch tillage and 47 percent more after mulch tillage than conventional cultivars. Soil loss estimates for LBS were much lower than for conventional soybeans as simulated by a revised universal soil loss equation (RUSLE). Breeding for increased residue production in soybeans could produce significant environmental benefits as a soil conservation practice in reducing soil erosion. The conservation benefits of LBS can be realized if enhanced biomass production can be combined with adequate grain production.