密度与氮肥对机采棉生长特性及产量的影响

Effects of density and nitrogen fertilizer on growth characteristics and yield of cotton harvested by machine

[目的]随着拾花劳动力紧缺以及拾花价格上涨,棉花机械采收已成为主要的棉花采收方式,研究机采棉种植模式下种植密度和施氮量对棉花生长特性及产量的影响十分必要。[方法]以‘新陆中54号’为供试品种,采用裂区试验设计,主区为18和24万株·hm-22个种植密度,副区为0、170、320、470 kg·hm-24个施氮量。[结果]当种植密度为24万株·hm-2、施氮量320 kg·hm-2时,增产率和氮肥农学利用率最高,分别为33.64%和6.38 kg·kg-1,与最高产量差异不显著。在相同种植密度下,随着施氮量的增加,株高、倒3叶宽、真叶数、果枝数、茎粗、主茎日增长量和群体干物质积累量均增加;在相同施氮量条件下,随着种植密度的增加以上性状呈降低的趋势。增施氮肥及增加种植密度均会延长生育期。在种植密度为18万株·hm-2时,叶面积指数、单株结铃数、单铃质量、衣分、籽棉产量均随着施氮量的增加而增加,而在24万株·hm-2密度条件下表现为先增后减的趋势。农艺性状与产量构成因素呈正相关关系。增产率及氮肥农学利用率均随施氮量的增加先增后减,随种植密度的增加呈增加的趋势。[结论]南疆阿克苏地区棉花种植密度24万株·hm-2、施氮量320 kg·hm-2较为理想,增产率和氮肥农学利用率最高,产量较高,农艺性状符合机采的标准。

[Objectives]With the shortage of picking labor and the rising price of picking cotton,the mechanical harvesting of cotton has become the main way of harvesting cotton.It is necessary to study the effects of planting density and nitrogen application rate on cotton growth characteristics and yield under the machine harvested cotton planting mode.[Methods]The variety was‘Xinluzhong 54’.The design was the split zone test:2 planting densities in the main area(180,240 thousand plants·hm-2),and 4 nitrogen application rates(0,170,320,470 kg·hm-2)in the sub area.[Results]When the planting density was 240 thousand plants·hm-2 and the nitrogen application rate was 320 kg·hm-2,the yield and nitrogen agronomic efficiency were the highest,respectively 33.64%and 6.38 kg·kg-1.The difference was not significant with the highest yield.Under the same planting density,plant height,3rd leaf width,the number of true leaf,the number of fruit branch,stem diameter,the daily growth of the main stem and the accumulation of dry matter in the population increased with the increase of nitrogen application.Under the same nitrogen application rate,with the increase of planting density,the above traits decreased.Increasing nitrogen fertilizer and increasing planting density will prolong the growth period.When planting density was 180 thousand plants·hm-2,leaf area index,boll number per plant,quality of single boll,lint percentage and seed cotton yield increased with the increase of nitrogen application rate.When the planting density was 240 thousand plants·hm-2,the above traits increased first and then decreased.There was a positive correlation between agronomic traits and yield components.The increase rate and nitrogen agronomic efficiency increased first and then decreased with the increase of nitrogen application rate.The increase rate and nitrogen use efficiency increased with the increase of planting density.[Conclusions]When the density of cotton planting in southern Akesu was 240 thousand plants·hm-2,and nitrogen application rate was 320 kg·hm-2,the yield and nitrogen agronomic efficiency were the highest and the yield was higher.The agronomic characters conform to the standard of mechanical mining.