Conventional fertilizers have played an important role increasing the yield during the production of maize in China. However, a great deal of conventional fertilizers utilization with low nutrient use efficiency not only leads to enormous waste of resource, but also causes the related environmental risk. Fortunately, controlled-release fertilizers with high nutrient use efficiency and low nutrient loss ratio are essential for increasing crop yield, nitrogen (N) utilization efficiency, and reduction of potential environmental risk. Additionally, soil fertility affects grain yield and fertilization utilization efficiency remarkably in practice. Obviously, it is essential to identify the optimum contioiled-release urea (CRU) rate in different fields. Therefore, a pot experiment was conducted to explore the effects of controlled-release urea on yield and photosynthesis characteristics of maize under different soil fertility conditions from 2006 to 2007. In the trial, two types of controlled-release urea, CRU3Oand CRU60 with 30 d and 60 d release durations, were used compared with the conventional urea (U) under two soil fertility conditions. All six treatments were supplied with N 5.43 g pot-1, P2O52.10 gpot-1, andK2O 5.24 g pot-1 as base fertilizer. Biomass above ground, harvest index (HI), leaf area (LA), net photosynthetic rate (P^, chlorophyll content and nitrogen content were investigated. Biomass above ground was increased significantly by CRU, but the increasing effects were different to CRU30 and CRU60. Under low soil fertility conditions, the yield increase effect was CRU30>CRU60>U (P<0.05), and the dry matter weight in CRU30 treatment was 18.9% higher than that in U treatment. Correspondingly, under high soil fertility conditions, that was CRU60>CRU30>U (P<0.05), and the dry matter weight in CRU60 treatment was 18.29% higher than that in U treatment. In addition, CRU enhanced the drymatter distribution to grain and partial factor productivity from applied nitrogen (PFPN) significantly under two soil fertility conditions. Among all treatments for dry matter distribution after anthesis and PFPN, the effect of CRU30 was the highest under low soil fertility condition, however, the effect of CRU60 was the highest under high soil fertility condition. CRU improved the dry matter accumulation and partitioning to grain after anthesis, especially enhanced the biomass above ground per plant, grain number per ear and 1000-kernel weight remarkably because the treatments of CRU30 and CRU60 kept the LA, Pn, chlorophyll content and nitrogen content at a higher level after anthesis. Accordingly, the controlled-release urea with short release duration is suggested to be utilized as the base fertilizer under low soil fertility conditions, however, that with long release duration under high soil fertility conditions in practice.%氮肥是玉米生产中最重要的增产要素之一.为探明不同地力水平下控释尿素对玉米物质生产及光合特性的影响,采用盆栽试验研究了释放期不同的2种控释尿素(CRU30,释放期为30d;CRU60,释放期为60d)的作用效果,以普通尿素为对照(U).结果表明,控释尿素处理显著增加玉米干物质积累量,但释放期不同的控释尿素在不同地力水平下增产效果不同,低地力水平下增产效果为CRU30>CRU60>U(P<0.05),CRU30处理比施用普通尿素增产18.9%;高地力水平下增产效果为CRU60>CRU30>U(P<0.05),CRU60处理比U增产18.2%.与对照相比,控释尿素使干物质向开花后分配比例增加,氮肥偏生产力(PFPN)显著提高,低地力时CRU30最高,而高地力时CRU60最高.控释尿素处理的单株干物质积累量、穗粒数及千粒重显著增加,主要因为生育中后期叶面积、光合速率、叶绿素及叶片氮含量维持较高水平.所以,在等氮量做基肥一次性施入时,低地力水平下施用释放期较短的控释尿素为宜,而高地力水平下应施用释放期较长的控释尿素.
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