测墒补灌对冬小麦氮素积累与转运及籽粒产量的影响

2007-2009年,在田间条件下,以冬小麦品种济麦22为材料,以0-140 cm土层平均土壤相对含水量为指标设计4个测墒补灌试验处理:W0(土壤相对含水量为播种期80%+拔节期65%+开花期65%)、W1(土壤相对含水量为播种期80%+拔节期70%+开花期70%)、W2(土壤相对含水量为播种期80%+拔节期80%+开花期80%)和W3(土壤相对含水量为播种期90%+拔节期80%+开花期80%),研究不同水分处理对冬小麦氮素积累与转运、籽粒产量、水分利用效率及土壤硝态氮含量的影响。结果表明:(1)成熟期小麦植株氮素积累量为W1处理最高,W3处理次之,W0和W2处理最低,W0和W2处理间无显著差异;氮素向籽粒的分配比例为W2处理显著低于W1处理,W0、W1、W3处理间无显著差异。开花期和成熟期营养器官氮素积累量、营养器官氮素向籽粒中的转移量、成熟期籽粒氮素积累量均为W1>W3>W2>W0,各处理间差异显著。(2)随着小麦生育进程的推进,0-200 cm土层土壤硝态氮含量先降低后回升再降低,在拔节期最低。成熟期W0和W1处理0-200 cm土层土壤硝态氮含量较低,W2和W3处理120-200 cm土层土壤硝态氮含量较高。(3)W0处理小麦氮素吸收效率、利用效率和氮肥偏生产力最低;随灌水量的增加,氮素利用效率呈先升高后降低趋势;W1处理小麦对氮素的吸收效率和利用效率较高,氮肥偏生产力最高。W0处理水分利用效率较高,但籽粒产量最低;灌水处理籽粒产量、灌溉水利用效率和灌溉效益两年度均随测墒补灌量的增加而显著降低。在本试验条件下,综合氮素利用、籽粒产量、灌溉水利用效率及土壤中硝态氮的淋溶,W1是高产节水的最佳灌溉处理,在2007-2008年和2008-2009年度补灌量分别为43.83 mm和13.77 mm。

Effects of supplemental irrigation based on measured soil moisture on nitrogen accumulation, distribution and grain yield in winter wheat

Water shortage is a serious problem threatening sustainable agricultural development in the North China Plain, where winter wheat ( Triticum aestivum L.) is the largest water-consuming crop. Water-saving technique is one of the most important components in maintaining wheat cultivation system with sustainable production in this area. The objective of this study was to optimize irrigation schedule in order to obtain high yield and water use efficiency in wheat. Field experiments were conducted with the cultivar of Jimai 22 under high-fertilizer soil conditions during 2007-2009 years. The irrigation treatments were designed four supplemental irrigations based on average relative soil moisture contents at 0-140 cm layers, at sowing, jointing, and anthesis stages(80%, 65%, and 65% for treatment W0; 80%, 70%, and 70% for treatment W1; 80%, 80%, and 80% for treatment W2; 90%, 80%, and 80% for treatment W3, respectively), to examine effects of different irrigation treatments on nitrogen accumulation and translocation, grain yield, water use efficiency, and soil nitrate nitrogen leaching in winter wheat. The results showed that: (1) Plant nitrogen accumulation of wheat at maturity for treatment W1 was the highest, following by W3, W0, and W2 ( P <0.05). The rate of nitrogen distribution to grain for treatment W2 was significantly lower than W1, and the differences among treatment W0, W1, and W3 were no significant. Nitrogen accumulation amount in vegetative organs at anthesis and maturity, nitrogen translocation of vegetative organs to grain, and grain nitrogen accumulation amount at maturity all showed the order of W1>W3>W2>W0 ( P <0.05). (2)Nitrate nitrogen content in 0-200 cm layers decreased first, increased then, and decreased again with wheat growth process progress, reaching its lowest content at jointing stage. At maturity stage, soil nitrate nitrogen content in 0-200 cm soil layers of treatments W0 and W1 were significantly lower, while those in 120-200 cm soil layers of treatments W2 and W3 were higher. (3)Nitrogen uptake, use efficiency, and partial productivity of treatment W0 were the lowest. Nitrogen use efficiency increased first, decreased then with irrigation amount increasing. Nitrogen uptake and use efficiency of treatment W1 was higher while its nitrogen partial productivity was the highest. Water use efficiency of treatment W0 was higher than those of other treatments. However, grain yield was the lowest for treatment W0. In two years, grain yield, irrigation water use efficiency, and irrigation benefit for the three irrigation treatments decreased significantly when more water was supplied. Under the present experimental condition, the W1 regime was considered optimal irrigation treatment, which 43.83 and 13.77 mm of water were supplied during 2007-2008 and 2008-2009 years, respectively.