%A XIE You-Liang, HUANG Yu-Fang, LIU Chun-Sheng, QU Ri-Tao, SONG Hai-Yan %T Effect of in-Season Nitrogen Management on Grain Yield and Nitrogen Use Efficiency in Wheat %0 Journal Article %D 2010 %J Acta Agronomica Sinica %R 10.3724/SP.J.1006.2010.01578 %P 1578-1584 %V 36 %N 09 %U {https://zwxb.chinacrops.org/CN/abstract/article_4624.shtml} %8 2010-09-12 %X 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.