南疆干旱区连作棉田土壤养分及生物活性的初步研究

 对南疆不同连作年限棉田的土壤养分、土壤酶活性、土壤微生物数量进行研究。结果表明：（1）连作后土壤总盐、K^＋、Na^＋、速效钾迅速减少，有机质、全氮、速效氮、速效磷、有效锰与之相反,有效铁、有效铜、有效锌变化不规律;（2）连作后土壤脲酶、碱性磷酸酶、转化酶活性逐年增大，过氧化氢酶逐年减小；（3）连作土壤中细菌数量占绝对优势，放线菌、真菌的数量较少。细菌、放线菌、真菌、固氮菌数量先增后降，无机磷细菌0~20年逐年增大，20年以后逐渐减小；解钾细菌呈线性上升趋势；（4）土壤转化酶、脲酶、碱性磷酸酶活性可以作为评价土壤肥力的指标。通径分析表明，有机质、速效钾是土壤微生物及土壤酶活性的主要影响因素。

Preliminary Research on Soil Nutrients and Bioactivity in Continuous Cropping Cotton Fields of Dryland in South Xinjiang

The nutrient status,enzyme activites and soil microbes were investigated in continuous cropping cotton field in south Xinjiang.The results showed that the total salinity,sodium and potassium salts and exchangeable potassium trended to decline in continuous cropping cotton fields.On contrast,soil nutrients,soil enzyme activates and soil microbes were observed to accumulate.No significant difference was found for available iron,available copper and available zinc in continuous cropping cotton fields.The activ...