机采棉模式下氮肥运筹对棉花产量和养分吸收的调控

Regulation of Nitrogen Fertilizer Management of Cotton Yield and Nutrient Uptake Under the Machine Pick Cotton Pattern

为探明机采棉种植模式下氮运筹技术模式,通过田间试验,在不同施氮水平下,对不同产量水平下机采棉各生育期定点采集有代表性的植株样品,分析其干物质N、P、K含量,研究不同产量水平下机采棉各生育期吸收N、P、K的量与比例及其区别,以期探明确土壤-棉花体系养分吸收利用特征,及其与产量变化的匹配关系。结果表明：随着氮肥基施比例由0%提高到40%,在机采棉模式下,可形成7667.15 kg/hm^2超高产,7376.12 kg/hm^2的中高产,7212.33 kg/hm^2的一般产量3种水平;机采棉在苗期—蕾期主要吸收氮素养分,占棉花苗期—蕾期吸收养分总量的34.57%-48.52%。蕾期—花铃期对养分的需求量最大,吸收N量占棉花整个生育期吸收总N的66.14%-83.22%、吸收P2O5占总P2O5的52.39%-73.07%、吸收K2O占总K2O的75.57%-79.08%。机采棉种植模式下棉花对养分的需求表现出对氮需求较早,且量也较大;对磷的需求稍晚,但需求持续时间长;对钾的需求时间和强度处于居于氮、磷之间。结论：机采棉种植模式下,通过氮肥的基追比例运筹,能够调控棉花达到不同的产量水平。机采棉超高产棉花在单位面积上对N、P2O5、K2O的吸收量高于一般产量和中高产棉花的吸收量,而且对K2O吸收的绝对量最大。在不同产量水平下棉花对N、P2O5、K2O养分吸收比例总体上是相似的,但各生育期养分吸收比例有所差异。

To study nitrogen management technology under machine pick cotton planting mode, through fieldexperiment with different nitrogen levels, the author collected representative samples of plants with differentlevels of cotton production in the growth period fixed points on a regular basis under the machine pick pattern,analyzed the content of N, P, K in the dry matter, studied the absorption of the N, P, K proportion and quantityand its difference in different growth periods, in order to explore soil- cotton system nutrient uptake characteristic, and its matching relation with output changes. The results showed that as basal application ofnitrogen fertilizer ratio from 0% to 40%, machine pick cotton mode could achieve super high yield of7667.15 kg/hm^2, high yield of 7376.12 kg/hm^2, and general yield of 7212.33 kg/hm^2. Nitrogen absorption was amajor nutrient at seedling stage and bud stage under the machine pick pattern, accounted for 34.57%-48.52% of the total absorption in this growth period of the cotton. The greatest demand for nutrients was the bud stageto the flowering and boll-setting period, the absorption of N accounted for 66.14%-83.22% of all cotton yield,the absorption P2O5 accounted for 52.39%-73.07% in all of the absorption P2O5, the absorption K2 O accountedfor 75.57%-79.08% in all of the absorption K2 O. Under machine pick cotton planting mode, the demand for Nwas earlier and higher, the demand for P2O5 was later and the longest. The time and strength demand for K werebetween the N and P2O5. Conclusion： machine pick cotton planting modes, through the management of base andtopdressing proportion of nitrogen fertilizer, could control the cotton production at different levels. In superhigh yield cotton field, the absorption of N, P2O5 and K2O were higher than that in medium high yield and thegeneral yield field, and its yield per unit area and the absorption of K2 O was the largest. Cotton under differentproduction levels had generally similar nutrient uptake ratio of N, P2O5, K2 O ratio, but there were differencesamong the nutrient uptake ratios in each growth period.