N 肥通常在冬小麦秋播前施于土壤表层。由于大多数作物要到第二年春暖时才吸收N 肥,一些 N 肥会淋失或分解成氨气跑掉。然而,大平原产区的多数试验表明,秋季或第二年春季施用 N 肥,产量相差不大。NH_4~+-N 的硝化、成为有机氮被固定以及在土层中的移动都能影响作物对它的利用。本试验旨在研究:大平原湿润地区冬小麦生长期间,秋施 NH_4~+-N 的固定、硝化、移动、植 N fertilizer is usually applied to the soil surface before winter wheat fall seeding. Since most crops will not absorb N fertilizer until the next spring, some N fertilizers will be leached or decomposed into ammonia gas to run away. However, most of the trials in the Great Plains show that there is not much difference in yields between using N fertilizer in autumn or next spring. Nitrification of NH_4 ~ + -N, as organic nitrogen is fixed, and the movement in the soil can affect crop utilization. The purpose of this experiment is to study the fixation, nitrification, movement and plantation of NH_4 ~ + -N during the winter wheat growth in the humid areas of the Great Plains.