长期定位施肥条件下黄土旱塬农田作物产量、水分利用效率的变化

以始于1979年的黄土旱塬黑垆土长期5种肥料试验为基础，研究了小麦、玉米一年一熟轮作条件下旱地作物产量及水分利用的变化。结果表明，无论气候年型如何，作物平均产量和水分利用效率大小依次为：有机无机肥结合（MNP）>秸秆还田与化肥配合（SNP）>单施化肥（NP）>单施农家肥（M）>单施化肥氮（N）>不施肥（CK）；MNP和SNP施肥方式在旱地农业生产中具有显著的增产和提高水分利用效率的作用，2种施肥方式下小麦平均产量较CK增加189%和158%，水分利用效率提高193%和 165%，玉米平均产量较CK增加125%和99%，水分利用效率提高121%和96%。随着试验年限的延长，化肥尤其是氮肥的增产效果受降水影响年际之间波动性很大, 但无机氮磷结合农家肥、无机氮磷配合秸秆还田能有效减缓产量的波动，起到抗逆减灾和稳定产量的作用。有机无机肥结合（MNP）和秸秆还田与化肥配合（SNP）是实现旱地有限水资源高效利用和旱地农业可持续发展的施肥方式。

CROP YIELD AND WATER USE EFFICIENCY UNDER LONG-TERM FERTILIZATION IN LOESS PLATEAU

Changes in grain yields and water use efficiency from a long-term fertilizer trail of 5 fertilization treatments in the dryland of Loess Plateau since the recorded 1979 were studied. The treatments were no fertilizer(CK), nitrogen fertilizer(N), manure fertilizer(M), nitrogen and phosphate fertilizers(NP), nitrogen and phosphate fertilizers with straw (SNP), nitrogen and phosphate fertilizers with manure (MNP). The results showed that whatever the year′s type of climate was, the crop yield and water use efficiency were coincident, the sequence was MNP>SNP>NP>M>N>CK. MNP and SNP could increase grain yield, improved water use efficiency. The average wheat yield of MNP and SNP increased by 189% and 158% , and water use efficiency increased by 193% and 165% compared with CK. The average corn yield of MNP and SNP increased 125% and 99%, and water use efficiency increased by 121% and 96% compared with CK. With the extension of trial period, inorganic fertilizer, especially nitrogen′s effect was influenced by annual precipitation, and the volatility of yield between years was bigger than that of other treatments. Inorganic nitrogen and phosphorus combined with manure(MNP), inorganic nitrogen and phosphorus combined with straw(SNP) could reduce output fluctuations, played important role to mitigate output reduction and stable yield in dryland agriculture. MNP and SNP were good fertilization methods to achieve high-efficient use limited water resources and sustainable development of dryland agriculture.