中国冬油菜氮素养分管理策略

Integrated Nitrogen Management Strategy for Winter Oilseed Rape(Brassica napus L.) in China

油菜是中国重要的油料作物,长江流域是其最主要种植区域,该区域的气候、土壤和种植制度决定了土壤养分供应特征、油菜生长和养分需求特征。作物高产、经济和养分高效是农业生产及其可持续发展的决定因素,油菜氮素吸收和土壤氮素供应在时间和空间上的不协调造成氮的缺乏或过量是油菜产量和收益的重要限制因子,合理的氮肥施用是保证油菜高产和氮肥高效的关键。论文从作物氮素需求、土壤氮素供应、氮肥施用关键技术及其配套措施等方面综述了国内外油菜氮肥管理的进展。在此基础上,结合中国冬油菜种植区域土壤和作物的特点,提出以"前促后稳"为核心,协调作物氮素需求和土壤氮素供应的冬油菜氮素养分综合管理策略。该策略的核心内容是:通过调节氮肥施用时期、比例和配比,满足油菜前期快速生长的氮素需求,后期则主要通过发挥土壤氮素供应,促进油菜氮素转移再利用;综合考虑不同轮作、秸秆还田条件下土壤氮素供应特点及后效,统筹氮肥的施用;配合合理密植、水肥管理、同其他元素肥料配施、机械深施等措施,以协同增效的方式实现油菜的高产和氮肥的高效。

Oilseed rape is one of the predominant oil crops in China. Yangtze River Basin is the key winter oilseed rape production region in China, where the specific climatic conditions, soils and cultivation practices induce the different characteristics of soil nutrient supply, crop growth and nutrient demand. High crop yield, high economic benefit and high nutrient use efficiency are the determinants of agricultural production and sustainable development. Asynchrony between oilseed rape nitrogen （N） demand and soil N supply in space and time is the major reason that excessive N or deficient N input is the most important limiting factor of rapeseed yield and economic benefit. Optimal N fertilization is critical to achieve high seed yield and high N fertilizer use efficiency. In this paper, the authors reviewed the recent perspectives on oilseed rape N management, including crop N uptake, soil N supply, the critical N fertilizer application methods and the matching techniques. Further, considering the characteristics of crop growth and soil N supply, an integrated N management strategy, of which the key is ＂promotion in early and stabilization in late＂ to match crop N uptake and soil N supply, is put forward. The core content of the strategy includes （1） adjusting the timing and proportion of N fertilization and N sources to satisfy N requirement in the seedling period, focusing on soil N supply to promote N transfer and re-utilization since stem elongation period; （2） Depending on soil N supply under different rotations and/or crop straw incorporation, coordinating the distribution of N fertilizer in whole growing season; （3） Synergistic interaction with other practices including optimal plant density, fertigation, application with other nutrients and mechanization to obtain high seed yield and high N fertilizer use efficiency.