Evaluation of management practices for converting grassland back to cropland

ABSTRACT:

Minimum-till (MT) and no-till (NT) systems were evaluated for converting seeded grassland back to cropland. Nitrogen fertilization need to optimize grain yields following grass and to optimize hay yields from the grassland were also evaluated Tillage treatments — conventional till (CT), MT, and NT — were established on a Weld silt ham soil that had been seeded to grass about 30 yr following more than 30 yr of crop-fallow. Nitrogen treatments were 0, 45, and 90 kg N/ha (0, 40, and 80 16 N/a) applied to each crop in a winter wheat (Triticum aes-tivurn L.)-corn (Zea mays L.)-fallow rotation or annually to grass plots. Residue cover at wheat planting averaged 18, 44, and 73% for CT, MT, and NT, respectively. Soil water recharge was minimal between grass kill and wheat planting however, soil NO₃-Nincreased 115, 69, and 54 kg N/ha (103, 62, and 48 16 N/ac) for CT, M7, and NT respectively. Wheat grain yields were greater with CT2,685 kg/ha (40 bu/ac) and MT 2,558 kg/ha (38 bu/ac) than with NT 2,052 kg/ha (30.5 bu/ac) . Lower wheat yields with NT resulted from lack of grass control. Wheat yield responses to N varied with year and were dependent on available water supplies. Corn grain yields were low [1,233, 2,063, and 1,564 kg/ha (19.7, 32.3, and 24.3 bu/ac) for CT, MT, and NK respectively]due to limited growing season water. Average wheat 6,238 kg/ha (5,623 lb/ac) and corn 5,040 kg/ha (4,500 lb/ac) plytomass production exceeded that of the fertilized grass [1,529 kg/ha with 90 kg N/ha (1,365 Mac with 80 16 N/ac)]. Producers converting CRP pass to crop production can use MT and NT practices to maintain soil erosion control.