氮素实时管理对冬小麦产量和氮素利用的影响

为实现氮素效率和小麦产量的协同提高,以山东省泰安市和兖州市为试验地点,连续2年在4个田块上进行了基于土壤硝态氮测试的氮素实时管理试验。与农民习惯施肥相比,优化施氮处理提高产量0.87%～10.44%,平均5.82%;而氮肥用量减少38.61%～53.29%,平均46.70%;氮素吸收效率、氮素表观利用率和氮素农学效率分别增加36.67%～85.69%、58.49%～267.69%和34.16%～410.58%;氮肥偏生产力升高74.23%～124.87%;产/投比提高78.50%～112.09%。说明应用土壤硝态氮测试进行小麦氮肥实时实地管理达到了减少氮肥用量,提高氮素利用效率,增加产量和经济效益的目的。

Effect of in-Season Nitrogen Management on Grain Yield and Nitrogen Use Efficiency in Wheat

Heavy nitrogen (N) fertilization is traditionally accepted by farmers in high-yielding wheat (Triticum aestivum L.) production. This fertilization strategy not only results in low N use efficiency and environmental pollution but also restricts to achieve high yield potentials of wheat cultivars. Site-specific N management is based on an in-season assessment of nitrate nitrogen (NO₃^--N) in soil and the required N quantity of wheat. Although the optimal N application rate during wheat growth period has been widely studied, including in-season N fertilization management, there is no an applicable fertilization scheme based on NO₃^--N monitoring for wheat fields with yield higher than 7500 kg ha^-1. In this study, four locations from typical high-yielding regions in Tai’an and Yanzhou of Shangdong province, China were selected as experimental sites, and local wheat cultivars were planted for treatments of in-season optimized N management (OPT) and farmer’s traditional fertilization (FR) under two growing seasons. According to yield target of 7 500 kg ha^-1, the N supply amount in OPT treatment was defined as pure N of 150 kg ha^-1 from sowing to jointing and 210 kg ha^-1 from jointing to maturity. A total of 125.1–155.5 kg ha^-1 and 125.9–164.4 kg ha^-1of N fertilizer were used in 2004 and 2005 year, respectively. In FR treatments, approximately 267.8 kg ha^-1 of N was applied, which was higher than that of OPT treatment by 38.61%–53.29%. Grain yield of OPT treatment was higher than that of FR treatment by 0.87%–10.44% with an average of 5.82%. Compared with FR treatment, OPT treatment had higher levels of several indices of N utilization. For instance, N uptake efficiency increased by 36.67%–85.69%, N recovery efficiency increased by 58.49%–267.69%, N agronomy efficiency increased by 34.16%–410.58%, and N partial factor productivity increased by 74.23%–124.87%. The value/cost ratio in OPT treatment was larger than that in FR treatment by 78.50%–112.09%. These results suggested that in-season N management strategy based on soil nitrate N test may reduce N application rate, increase N use efficiency, grain yield, and value/cost ratio in wheat.