吐鲁番哈密瓜土壤养分及酶活性对连作年限的响应

哈密瓜(Cucumis melo var.saccharinus)连作障碍已经成为制约其产业发展的重要因素,为探明哈密瓜连作年限对土壤养分及酶活性的影响,以吐鲁番鄯善县不同连作年限哈密瓜田为研究对象,分析了不同连作年限哈密瓜农田根际土壤及非根际土壤的养分含量及酶活性特征。结果表明:1)随连作年限的递增,哈密瓜根际土壤和非根际土壤中有机质、全氮、全磷、微生物量碳、微生物量氮含量均呈现先升高后降低的趋势,且在6~10年达到最大值;2)随连作年限的递增,哈密瓜根际土壤和非根际土壤中酶活性的变化趋势基本一致,过氧化氢酶活性在不同连作年限之间无显著差异,碱性磷酸酶活性呈现先下降后升高的趋势,硝酸还原酶活性呈现逐年下降的趋势,脲酶、蔗糖酶、纤维素酶活性呈先升高后降低的趋势,且在6~10年达到最大值;3)土壤养分元素含量、酶活性均受到连作年限及土壤采样部位的双重影响,但连作年限对土壤养分元素含量及酶活性的影响较强。总体上在连作年限为6~10年时,土壤中养分含量与总体酶活性均呈现较高的水平,而后逐年递减。

Response of soil nutrient and enzyme activity to continuous cropping years of Turpan Hami melon

The continuous cropping obstacle of Hami melon(Cucumis melo var.saccharinus)has become an important factor restricting its industrial development.In order to find out the effect of continuous cropping years on soil nutrients and enzyme activities,the characteristics of nutrients and enzyme activities in the rhizosphere soil and non-rhizosphere soil of Hami melon fields with different continuous cropping years in Eastern Turpan were analyzed.The results showed that:1)With the increase of continuous cropping years,the contents of organic matter,total nitrogen,total phosphorus,microbial biomass carbon and microbial biomass nitrogen in Hami melon rhizosphere soil and non-rhizosphere soil increased first and then decreased,and reached the maximum value in 6 to 10 years;2)With the increase of continuous cropping years,there was no significant difference in the activity of catalase between different continuous cropping years,and the activity of alkaline phosphatase decreased first and then increased.The activities of urease,sucrase and cellulase increased first and then decreased,and reached the maximum in 6 to 10 years;3)Soil nutrients and enzyme activities are affected by continuous cropping years and soil sampling area,among which continuous cropping years account for a large proportion.When continuous cropping years are 6~10 years,soil nutrient content and overall enzyme activity remain at a high level,and then decrease year by year.