氮肥滴施次数及比例对机采棉产量和氮肥利用率的影响

【目的】 研究氮肥随水滴施次数和分配比例对机采棉生长、产量以及氮肥利用率的影响。【方法】 2017~2018两年田间试验,设置5个处理:(1)不施氮肥(CK),(2)施肥8次+前轻后重(习惯施肥,N8-B),(3)施肥8次+前重后轻(N8-F),(4)施肥10次+前轻后重(N10-B),(5)施肥10次+前重后轻(N10-F)。【结果】 增加氮肥施用次数显著提高棉花干物质重和氮素吸收量。在相同氮肥滴施次数下,氮肥分配“前重后轻”处理(F)棉花干物质重和氮素吸收量均显著高于“前轻后重”处理(B)。2017和2018年,施肥10次处理棉花产量较施肥8次处理分别增加17.9%和34.7%,棉花氮肥利用率分别提高了24.02和28.61个百分点。N8-F和N10-F处理棉花产量较相同施肥次数的N8-B和N10-B处理分别增加7.0%~11.1%和12.1%~21.5%,氮肥利用率分别提高了12.0~26.5和11.2~24.9个百分点。【结论】 增加氮肥滴施次数及前期施用比例可促进滴灌机采棉生长和氮素吸收,提高机采棉产量和氮肥利用率。

Effects of Nitrogen Fertigation Frequency and Proportion on Yield and Nitrogen Use Efficiency of Machine-picked Cotton

【Objective】 A field experiment was conducted to examine the effects of nitrogen (N) fertigation frequency and proportion on yield and N use efficiency of machine-picked cotton under drip irrigation conditions from 2017 to 2018. 【Methods】 The experiment consisted of 5 treatments: (1) control (no N fertilization (CK); (2) N fertigation 8 times plus former-lower-latter-higher (farmers conventional fertigation, N8-B), (3) N fertigation 8 times plus former-higher-latter-lower (N8-F), (4) N fertigation 10 times plus former-lower-latter-higher (N10-B), (5) N fertigation 10 times plus former-higher-latter-lower (N10-F).【Results】 Increasing the frequency of N fertigation significantly increased the dry matter weight and N uptake of cotton in both 2017 and 2018. Under the same N fertigation frequency, the dry matter weight and N uptake of cotton were significantly higher in the former-higher-latter-lower treatments (F) than those in the former-lower-latter-higher treatments (B). Compared with N8 treatments, the yield of cotton in N10 treatments increased by 17.9% and 34.7% respectively, in 2017 and 2018; and NUE of cotton increased 17.9 and 34.7 percentage point, respectively. The yield of cotton in N8-F and N10-F treatments were 7.0% - 11.1% and 12.1% - 21.5% higher than those under N8-B and N10-B treatments. NUE of N8-F and N10-F treatments were 12.0-26.5 and 11.2-24.9 percentage points higher than those of N8-B and N10-B treatments, respectively. 【Conclusion 】 Increasing N fertigation frequency and the proportions at the early stage can promote the growth and N uptake, and increase the yield and NUE of machine-picked cotton.