耕作方式对冬小麦氮素积累与转运及土壤硝态氮含量的影响

以济麦22为试验材料，在大田条件下设置条旋耕（SR）、深松+条旋耕（SRS）、深松+旋耕（RS）、旋耕（R）和翻耕（P） 5个耕作方式处理，研究了耕作方式对冬小麦氮素积累、分配和转运及土壤硝态氮含量的影响。结果表明，1）深松+条旋耕和深松+旋耕处理小麦开花至成熟期20140 cm各土层的土壤含水量较低; 拔节期之后的小麦氮素吸收强度、开花和成熟期植株氮素积累量、成熟期氮素向子粒中的分配比例及开花期营养器官中贮存的氮素向子粒中的转运量均高于条旋耕和旋耕处理; 深松+条旋耕和深松+旋耕处理成熟期氮素向子粒中的分配量高于翻耕，翻耕高于旋耕和条旋耕处理。2）深松+条旋耕和深松+旋耕处理成熟期080 cm各土层的土壤硝态氮含量低于翻耕处理，翻耕低于旋耕和条旋耕处理，条旋耕最高; 深松+旋耕在120160 cm土层的土壤硝态氮含量高于其他处理; 各处理在160200 cm土层的土壤硝态氮含量无显著差异。3）深松+旋耕和深松+条旋耕的子粒产量和氮肥偏生产力最高且两者无显著差异，翻耕次之，旋耕和条旋耕低于上述处理。在本试验条件下，综合考虑氮素利用、子粒产量和土壤中硝态氮的淋溶，深松+条旋耕为最佳耕作方式，可供生产中参考。

Effects of tillage practices on nitrogen accumulation and translocation in winter wheat and NO3--N content in soil

 Conservation tillage practices, including no tillage, rotary tillage, subsoil tillage and so on, are applied widely for wheat (Triticum aestivum) production in Northern China. They are primarily used because of their positive effects on soil fertility, water conservation and crop yield. Tillage practices affect not only soil properties and grain yield but also plant nitrogen metabolism. To determine the effects of tillage practices on nitrogen accumulation, distribution, translocation and soil NO₃^- -N content, a field experiment was carried out on high fertility soil with organic matter 14.5 g/kg, alkali hydrolysable N 106.8 mg/kg, available P 35.2 mg/kg and available K 116.9 mg/kg in Shijiawangzi village, Yanzhou city, Shandong province, China, using the wheat cultivar, Jimai 22, which has high yield and medium gluten potential. There were five treatments, strip rotary tillage (SR), strip rotary tillage after subsoiling (SRS), rotary tillage (R), rotary tillage after subsoiling (RS) and plowing tillage (P). There were three replicates for each treatment. The plot area was 4 m×4 m and a 2 m wide protective belt was left between every two adjacent experimental plots. The basic seedling number was 180 plant/m². The results indicate that the soil moisture contents of SRS and RS  treatments  in 20-140 cm layers are lower than those of the SR and R treatments from the anthesis to the maturity, respectively. The nitrogen uptake intensities after the jointing, nitrogen accumulation amounts in plant at the anthesis and the maturity, nitrogen distribution proportions in grain at the maturity and the nitrogen translocation amounts from vegetative organs to grain after the anthesis are higher in SRS and RS treatments than those in SR and R treatments. The nitrogen distribution amounts in grain at the maturity are the highest in SRS and RS treatments, and followed by P  treatments  which is higher than those in SR and R  treatments. The soil NO₃^- -N contents in 0-80 cm soil layers in SRS and RS  treatments are lower than that in P treatment, and the contents in SR and R  treatments are higher than that in P treatment, in which the content in SR  treatment  is the highest. The soil NO₃^- -N content in 120-160 cm soil layer of RS is higher than those of the others, and there are no significant differences of the contents in 160-200 cm soil layers among the five treatments. The SRS and RS  treatments  gain the highest grain yields and nitrogen partial factor productivity which have no significant differences between them, and then the P  treatment, followed by R and SR  treatments. Based on a comprehensive consideration of nitrogen use efficiency, grain yield and soil NO₃^- -N content, we recommend that the SRS is the most appropriate tillage practice in high yield and benefit production of wheat in Northern China.