棉花连作对土壤养分、微生物及酶活性的影响

The Influence of Cotton Cropping Cotton Soil on Soil Nutrient,Microorganisms,and Soil Enzyme Activity

对南疆不同连作年限棉田的土壤养分、土壤酶活性、土壤微生物数量及其相关性进行研究,结果表明:有效铁、Cl-、SO42-、Ca2+、Mg2+、总盐、Na+、pH减少,K+、速效钾15年减少20年增加,其余土壤养分指标增加;细菌是土壤中微生物的主体,随着连作年限的增加真菌数量略有增长,细菌、放线菌、固氮细菌、无机磷细菌、解钾细菌数量减少;土壤酶活性提高;相关分析表明土壤养分与真菌、土壤酶呈正相关,与其它5种微生物数量呈负相关。连作后土壤养分的提高促进土壤酶活性,而抑制土壤微生物生长。用土壤转化酶、脲酶、碱性磷酸酶作为评价土壤肥力的指标具有一定可靠性。

Soil nutrient, soil enzyme activeity, microbial quantity and the correlation along them of contimuous cropping cotton soil in south xinjiang were studied. The result indicated that numerical value of effective iron, Cl-. SO4^2- . Ca2＋ . Mg2＋ , the total salt, Na ＋ and pH decreased and numerical value of other soil nutrient increased along with continuous cropping year increase, while numerical value of K＋ and the fast -acting pdotassium decreased after continuous cropping for 15 years and increased after continuous cropping for 20 years. The number of bacterium was the highest of the soil microorganism. Along with continuous cropping year increased, the quantity of fungus grown slightly, while the quantity of bacterium, the ray fungi, the nitrogen - fixing bacteria, the inorganic phos- phobacteria, solution potassium bacterium was reduced and the activity of soil enzyme was enhanced. The results of correlation analysis indicated that the soil nutrient was positive correlation with the fungus and the soil enzyme, and was negative correlation with quantity of other 5 kinds of microorganism. The result also indicated that enhancement of soil nutrient promoted the activity of soil enzyme, but suppressed growth of soil organisms along with continuous cropping year increased. It was certain reliability that the soil invertase, the urease and the alkalinity phosphatase were regarded as the soil fertility＇s evaluation index.