CORN YIELD, RUNOFF, AND SEDIMENT LOSSES FROM MANURE AND TILLAGE SYSTEMS

One challenge in land application of manure is to maximize its benefit to crops without harming the environment, Our objective was to evalua te the impart of manure addition on corn yield, and sediment losses in snowmelt and rainfall runoff under moldboard plow (MP) and ridge till age (RT) systems, Corn (Zea mays L.) grain yield and sediment losses i n surface runoff after a one-time spring application of (16.2 dry Mg h a(-1)) solid beef (Bos taurus) manure on a 12% slope Forman (finc-loam y, mixed Udic Argiborolls)-Buse (fine-loamy, mixed Udorthentic Haplobo rolls) complex were measured from 1992 through 1994. In 1993, there wa s no effect of manure on grain yield irrespective of tillage because o f high rainfall. Under average rainfall conditions in 1994, grain yiel d (10.2 Mg ha(-1)) in the manure RT treatment was 1.0, 0.9, and 0.7 Mg ha(-1) greater than that in no-manure RT,manure MP, and no-manure MP treatments, respectively, Snowmelt runoff was not affected by manure a pplication and it transported <0.1 Mg sediment ha(-1). Manure reduced rainfall runoff by 10 mm in 1993 and 3.2 mm in 1994, which led to redu ction in sediment lass of 25 and 0.2 Mg ha(-1), respectively. The RT s ystem resulted in lower rainfall runoff compared with the MP system fo r all 3 yr. Onetime manure application reduced rainfall runoff and ass ociated sediment loss in both tillage systems. However, manure applica tion was more effective in minimizing runoff and sediment losses durin g Intense rainfall in the RT than in the MP system.