长期施肥对我国6种旱地小麦磷肥回收率的影响

为阐明长期施肥下小麦磷肥回收率的时间及空间变化特征，对我国6种旱地土壤（红壤、黑土、均壤质潮土、轻壤质潮土、塿土和黄棕壤）长期不同施肥下的磷肥回收率及相关指标进行了分析。结果表明，长期施用NPK化肥（NPK），均壤质潮土、轻壤质潮土、塿土、黄棕壤上小麦当季磷肥回收率随时间增加而显著升高，每年平均分别上升 0.80、0.60、1.30和0.44个百分点；化肥有机肥配施（NPKM），每年平均上升0.25～1.72个百分点。黑土上小麦磷肥回收率长期施用NPK的变化不大，施用NPKM的显著升高，平均每年上升 0.50个百分点；红壤上磷肥回收率NPK处理呈下降趋势，平均每年下降 0.86个百分点，而NPKM处理保持平稳，说明施用有机肥有利于提升磷肥回收率。不同土壤上小麦当季磷肥回收率的变化速率与土壤磷的形态密切相关，以无机钙磷为主要形态的土壤（均壤质潮土、轻壤质潮土、塿土）小麦磷肥回收率均高于以有机磷为主要形态的黑土和以无机闭蓄态磷为主要形态的红壤。小麦当季磷肥回收率受土壤性质的影响，与土壤全磷和pH值之间具有显著的正相关关系（P0.05）。

Influences of long-term fertilizations on phosphorus recovery efficiency of wheat in six dry upland soils of China

Based on long-term experiments in six upland soils (black soil, isotropic fluvo-aquic soil, fluvo-aquic soil, manural loess soil, red soil and yellow-brown soil), recovery efficiency of phosphorus (PRE) on wheat and its correlative parameters were analyzed to study the temporal and spatial changes of PRE on wheat under various long-term fertilizations. Results indicate that PREs on wheat in the isotropic fluvo-aquic soil, fluvo-aquic soil, manural loess soil and yellow-brown soil are increased annually by 0.80, 0.60, 1.30, and 0.44 percentage points with NPK application (chemical N, P and K fertilizers), respectively. PREs are increased by 0.25–1.72 percentage points with NPKM application (chemical N, P, K fertilizer combined with organic manure) on the four soils. For the black soil, PRE is unchanged during the long-term application of NPK, while that is increased annually by 0.50 percentage points with NPKM. However, PRE in red soil is decreased annually by 0.86 percentage points with long-term application of NPK, and unchanged with long-term application of NPKM. These results indicate that the application of organic manure is helpful to increase PRE in upland soils. The change rate of PRE is related with the fractions of soil phosphorus at the six sites. In isotropic fluvo-aquic soil, fluvo-aquic soil and manural loess soil, the main fraction of soil phosphorus is Ca-P, the PRE change rates of these soils are higher than those of black soil with the main fraction of organic-P and red soil with the main fraction of occluded-P. There are significant positive correlations between PRE and TP (total phosphorus) and soil pH respectively (P<0.05).