Nitrogen Mineralization Responses to Cropping, Tillage, and Nitrogen Rate in the Northern Great Plains

摘要: Nitrogen-mineralization rates are needed to accurately determine N fertilization requirements meet plant needs while minimizing environmental contamination. A spring wheat (Triticum aestivum L.)-fallow (SW-F) system was compared with a wheat-winter wheat-sunflower (Helianthus annuus L.) (SW-WW-SF) on Temvik-Wilton silt loam (fine-silty, mixed Typic and Pachic Haploborolls) at three (0, 22, 45 kg ha -1 for SW-F 34, 67, 101 - 1 SW-WW-SF) under conventional, minimum, no-tillage. After 10 yr, soil samples were incubated N-mineralization rates. Cropping intensity, rate, tillage intensity interacted affect Within the in 0- 0.05-m depth 8.2 ± 0.8 wk fallow phase vs. 5.0 0.7 crop conventional 6.2 0.3 minimum no-tillage both phases. The 2.3 0.4 0.05- 0.15-m soils of system. In wheat, 9.9 SW-WW-SF 5.6 ' 3.6 0.1 2.4 0.2 system, layer 6.8 0.5 winter 9.2 0.6 sunflower. layer, 3.3 1.0 '. More intensive cropping conservation increased this may ameliorate decline fertility associated crop-fallow systems.