江汉平原棉花氮肥合理运筹技术研究

Nitrogen Fertilizer Application and Assignment Techniques of Cotton in Jianghan Plain

为了提出江汉平原地区棉花氮肥的合理运筹技术，采用田间小区试验研究了棉花氮肥品种的选择、合理的施氮次数,并探讨了气候条件的影响。结果表明，综合考虑棉花产量、经济效益、氮素吸收利用以及土壤中硝态氮残留等各种因素,普通尿素4次施氮和缓控释氮肥2次施氮都是较好的氮肥运筹方式。在氮肥施用的时间上宜采用“应变式”方式，雨后施氮,充分利用自然降雨发挥肥效，避免施氮肥后3～5d内出现大的降雨．施肥后如遏长时间干旱需及时灌溉。必要时还可根据棉花预期产量水平的变化调整施氮总量,并通过调整后期追氮量来实现，从而实现氮肥高效利用与棉花高产。

To establish nitrogen （N） fertilizer application assignment techniques of cotton in Jianghan plain, 2 field experi- ments were carried out to study the rational N fertilizer type and application times, and the effect of climate conditions. Re- sults showed that if cotton yield and economic profit, N absorption and apparent recovery efficiency, and NO3^--N residual in soil were all taken into consideration, both ordinary urea being applied for 4 times and slow/controlled released N fertilizers being applied for 2 times were recommended. Flexible method should be used to the specific application time of N fertilizer. It is advised to apply N fertilizers after rain to make the best use of both natural rainfall and N fertilizers, to avoid heavy rain 3-5 days after N fertilizer application, and to irrigate cotton field if necessary. The total N fertilizer application rate might be adjusted according to predicted cotton yield goal by the subsequent top-dressing rate of N fertilizers,which could achieve high efficiency of fertilizer application and high yield of cotton.