水质与灌溉频率对棉花苗期根系分布的影响

本文试验研究了高含盐土壤滴灌条件下,水质与灌溉频率对棉花苗期根系分布的影响。试验土壤为砂质壤土(砂粒68%、粉粒24%、粘粒8%),土壤初始含盐量为0.8%。灌溉水质有3个水平,分别为CK(自来水)、S10(SAR=10/EC=3)与S5(SAR=5/EC=3);灌溉频率有3个水平,分别为每4天、每8天、每16天灌溉一次。试验结果表明:棉花苗期,80%以上的根系总干重分布于距地表0-20cm的根层内;与优质水比较,采用微咸水滴灌有助于提高棉花苗期的根系总干物质量。低频灌溉有助于促进棉花苗期根系的发育;灌溉频率降低时,各层根系增大的百分比随着深度增加而增大;根系总干重的增大主要是靠10cm以下各层根重密度的增大来实现的;棉花苗期,低频灌溉有利于深层根系干物质的积累。

EFFECTS OF WATER QUALITY AND IRRIGATION FREQUENCY ON ROOT DISTRIBUTION OF COTTON SEEDLING

Base on the resultof experiment,The affects of irrigation water qualityand drip irrigation frequency on root distribution of cotton seedling is analyzed.Sandy loam(sand 68%,silt 24% and clay 8%)with initial salt content of 0.8% is used for the experiment.The irrigation water quality has3levels,which is CK(tap water),S10(SAR=10,EC=3)and S5(SAR=5,EC=3)respectively.The irrigation frequency has 3 levels,which is high frequency(per 4 days),moderate frequency(per 8 days)and low frequency(per 16 days)respectively.The results indicated that more than 80% of total dry root weight of the cotton seedling locates in 0-20cm root layer.Compared with tap water,irrigated with saline water can improve development of root system of cotton seedling.Low irrigation frequency can enhance the development of root system and root dry weight density increase with decreasing irrigation frequency and increasing root depth.The increase of total dry root weight mainly comes from the increase of root dry weight in layer beneath depth of 10cm.Low irrigation frequency makes for accumulation of dry root weight of deeper cottonroot layer.