氮肥和土壤质地对滴灌棉花根系分布及产量的影响

Effect of Nitrogen Fertilization and Soil Texture on Cotton Root Traits and Yields Under Conventional Drip Irrigation

通过大田二因素随机区组试验,研究了滴灌条件下不同质地棉田土壤棉花根长密度和根表面积的垂直分布特征及其对产量的影响。结果表明:(1)施肥、灌水都可以显著降低棉花根长密度和根表面积,其关系表现为显著负相关;(2)花期之前棉花在0~20 cm土层根长密度表现为砂土>黏土>壤土,花期之后表现为砂土>壤土>黏土;在20~40 cm土层表现为壤土>黏土>砂土,且深层土壤砂土中棉花根长密度下降势显著高于壤土、黏土;在不同质地土壤中,粗根表面积均表现为N2(施氮量360 kg/hm^2)>N3(施氮量480 kg/hm^2)>N1(施氮量240 kg/hm^2)>CK(不施氮处理);(3)根系分布特征参数与籽棉产量相关性分析结果显示,根长密度、根表面积对籽棉产量的形成均有显著影响,棉花籽棉产量的有效提高手段之一是在某些特定生育期适度地降低根系特征参数。

A field experiment was conducted to study the effects of N fertilization and soil textures on cotton root characteristics and yield under conventional drop irrigation by using the method of minirhizotron technique and randomized field plots. The results showed that N fertilization and drop irrigation significantly reduced cotton length density and surface area, a significant negative correlation existed between fertigation and the two root parameters. Cotton root length densities in 0-20 cm were in an order of sand soil 〉 clay soil 〉 loam soil before flowering stage, but in an order of sand soil 〉 loam soil 〉 clay soil after flowering stage; Cotton length densities in 20-40 cm were in an order of loam soil 〉 clay soil 〉 sand soil, and it decreased significantly in sand soil than in other soil textures. The surface areas of coarse roots were in order of N2 （N 360 kg/hm^2） 〉 N3 （N 480 kg/hm^2） 〉 N1 （N 240 kg/hm^2） 〉 CK （no nitrogen）. Correlation analyses showed that cotton root length density and surface area significantly influenced cotton yield, which indicates that decreasing cotton root length density and surface area is conducive to promoting cotton yield.