滴灌条件下不同盐水平对棉花根系分布的影响

 通过盆栽试验研究膜下滴灌土壤盐分分布对棉花根系生长的影响。结果表明：受滴灌水分运移的影响，在0～30 cm土层形成脱盐区，土壤盐分明显下降，养分含量也很低，30 cm以下是积盐区。土壤盐分对棉花根系分布影响显著，0.32 dS·m^-1、1.12 dS·m^-1和1.90 dS·m^-1处理总根长分别为26.35 m、49.54 m和34.40 m，但在土层表现不同。在0～30 cm脱盐区内，1.12 dS·m^-1和1.90 dS·m^-1处理的根长密度明显高于0.32 dS·m^-1处理，而在40～50 cm却低于0.32 dS·m^-1处理。研究认为，在盐胁迫条件下，棉花根系分布进行适应性变化，产生补偿效应，通过显著的增加脱盐区（0～30 cm土层）根系数量，来获得更多的水分、养分保证棉花生长的需要。

Effects of Different Soil Salinity Levels on the Distribution of Cotton Root in Drip Irrigation under Film

A pot experiment was carried out to evaluate the effect of soil salinity distribution on growth and distribution of cotton root.The result showed that there was a desalted zone at 0～30 cm depth with water motion，the desalted zone which maintained an environment of lower salinity and nutrient，and the salt accumulation zone was under 30 cm. The distribution of root in different soil salinity treatments was significantly different (P<0.05)，the total root length was 26.35 m、49.54 m and 34.40 m for EC_1.5 treatments 0.32、1.12 and 1.90 dS·m^-1, respectively，but distribution of root was different in different soil depth. The root length densities for EC_1.5 treatments 1.12 and 1.90 dS·m^-1 were significantly higher（P<0.05 ）  than 0.32 dS·m^-1  at 0～30 cm soil depth, in which salinity was desalted，but the root length density was decreased when soil salinity increased from 0.32 to 1.90  dS·m^-1 at 30～50 cm depth. The cotton root would adjust its distribution by salinity stress and produce compensatory effect，the root quantity in salinity desalted zone was significantly increased when the root absorbed more water and nutrient.