江汉平原麦后移栽棉适宜施氮量研究

为探寻江汉平原棉区麦后移栽棉模式最适宜施氮量，以中棉所63为研究对象，于2018—2019年连续2年进行不同施氮量（0、90、180、270、360、450 kg·hm-2）的田间小区试验，研究施氮量对麦后移栽棉的生长、产量及氮肥利用率的影响。研究表明：随着施氮量的增加,棉株倒4叶SPAD值呈增加趋势，花铃期倒4叶SPAD值与施氮量呈极显著一元二次关系。以施氮量在270~360 kg·hm-2之间籽棉占整株干物质量比例较大，且氮素向生殖器官转移速率最大。施氮量360 kg·hm-2处理的棉花产量、氮肥表观利用率、氮肥贡献率均最高。采用线性加平台模型拟合得出麦后移栽棉适宜施氮量为318.75 kg·hm-2（2018年）、310.64 kg·hm-2（2019年）,产量潜力可达到4 463.58 kg·hm-2(2018年)、4 662.53 kg·hm-2（2019年）。综合棉花生长、产量、氮素迁移及利用的结果，推荐江汉平原麦后移栽棉适宜施氮量为310.64～318.75 kg·hm-2。

Study on the Optimal Nitrogen Application Rate for Transplanted Cotton following Wheat Harvest in Jianghan Plain

In order to find out the optimal nitrogen application rate for transplanted cotton following wheat harvest mode in Jianghan Plain using cotton CCRI 63, this paper carried out the field plot test for six N application rate treatments(0, 90, 180, 270, 360 and 450 kg·hm-2) during 2018 and 2019 and studied the effects of nitrogen rate on the growth, yield and nitrogen use efficiency of cotton transplanted after wheat. The results showed that the SPAD value increased with the increase of nitrogen application rate and had a univariate quadratic relationship with nitrogen application at flowering and boll-forming stage. The seed cotton accounted for a larger proportion of the whole plant when the nitrogen application rate was 270~360 kg·hm-2. The rate of nitrogen transfer to the reproductive organs was the highest. The yield, apparent nitrogen use efficiency and nitrogen fertilizer contribution rate were the highest under 360 kg·hm-2 nitrogen treatment. A linear plus platform model was used to fit the optimal economic nitrogen application rates that was 318.75 kg·hm-2 (2018) and 310.64 kg·hm-2 (2019) for transplanted cotton following wheat harvest in the Jianghan Plain. The potential yield was 4 463.58 kg·hm-2(2018) and 4 662.53 kg·hm-2(2019) respectively. Based on the results of cotton growth, yield and nitrogen migration and utilization, it was suggested that the suitable nitrogen application rate was 310.64~318.75 kg·hm-2 for post-wheat transplanted cotton in the Jianghan Plain.