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通过西北典型旱地渭北旱塬5年定位试验,在施磷100kgP2O5·hm-2的基础上,设0、80、160、240、320kgN·hm-25个施氮水平,结合5年降水情况,研究了播前底墒与施用氮肥对旱地冬小麦产量及水分利用的影响.结果表明:夏季7—9月的降水与播前底墒呈线性相关,每增加1mm夏季降水,土壤贮水量增加0.6mm;要保持小麦稳产或高产,底墒应保持在550mm左右,夏季降水应有370～390mm.夏季降水充足(>386mm)的年份,前季小麦施氮量增加造成的下季小麦播前底墒下降不明显;降水偏少(<350mm)的年份,前季小麦每增施氮肥100kg·hm-2,可使下季小麦播前底墒减少9～17mm.除底墒外,关键生育期的充足降水也是保证旱地小麦产量的重要因素,每毫米播前底墒和关键生育期降水分别能形成10.6～11.4和30.6～33.1kg·hm-2小麦籽粒产量.变异分析表明,氮肥投入水平影响小麦对底墒的利用程度,底墒制约小麦植株干物质向籽粒转移的比例.
Based on the five-year experiment of Weibei Arid Plateau, a typical dry land in the northwestern China, 0, 80, 160, 240 and 320 kg N · hm-25 nitrogen application rates were established on the basis of 100 kg P2O5 · hm- The effects of soil moisture before sowing and nitrogen fertilizer on the yield and water use efficiency of winter wheat in dryland were studied.The results showed that there was a linear correlation between precipitation and sowing soil moisture before and after sowing in July to September and the water storage capacity increased by 0.6mm for each additional 1mm summer precipitation Maintain a stable yield of wheat or high yield, bottom moisture should be maintained at about 550mm, summer precipitation should be 370 ~ 390mm. Summer precipitation sufficient (> 386mm) of the year, Precipitation less (<350mm) of the year, the first quarter of wheat nitrogen fertilizer for each additional 100kg · hm-2, sowing the next season can reduce the sowing moisture 9 ~ 17mm. In addition to the end of soil moisture, the key growth period of adequate precipitation is to ensure dry land wheat The grain yield of 10.6 ~ 11.4 and 30.6 ~ 33.1kg · hm-2 wheat was the key factor of yield per hectare before sowing and the critical period of precipitation.The variation analysis showed that the input level of nitrogen affected the utilization degree of soil moisture, Restricted the dry matter of wheat plants to The proportion of particles transfer.