氨基酸有机肥对棉花根际和非根际土壤酶活性和养分有效性的影响

在新疆石河子进行了2年不同氨基酸有机肥施用量的大田试验,测定棉花根际和非根际土壤酶活性和有效养分含量。结果表明,棉花根际土壤过氧化氢酶、蔗糖酶、磷酸酶、脲酶、纤维素酶活性高于非根际,且脲酶、纤维素酶活性达到显著差异。新陆早8号根际过氧化氢酶活性高于新陆早12号,但蔗糖酶、磷酸酶、脲酶、纤维素酶活性低于新陆早12号。根际碱解N呈显著降低,速效P呈增加趋势。膜下滴灌根际和非根际土壤过氧化氢酶、磷酸酶、脲酶、土壤pH及非根际的碱解N、速效P、根际的速效K较淹灌高,而土壤蔗糖酶、纤维素酶、根际碱解N、速效P、非根际的速效K较淹灌低。氨基酸有机肥对棉花根际和非根际土壤酶活性都有增加作用。土壤pH随着有机肥施用量的增加呈下降趋势,根际低于非根际。氨基酸有机肥增加了土壤碱解N、速效P、速效K含量。

Effects of application amino acid fertilizer on soil enzyme activity and available nutrients in cotton rhizosphere and bulk soils

Field experiments were carried out to study the effects of applying an amino acid fertilizer on enzyme activities and available nutrients in rhizosphere and bulk soils of two varieties of different disease-resistance cotton at Shihezi city in Xinjiang in 2006 with open flooding irrigation and in 2007 with film-covered trickle irrigation. Soil samples were collected at the bolling stage. The results showed that the activities of catalase, alkaline phosphatase, urease and cellulase, urease and cellulase were significantly higher in rhizosphere soils than those in bulk soils. The activities of catalase, alkaline phosphatase, urease and cellulase except catalase in rhizosphere soils of variety Xinluzao-8 were lower than those of variety Xinluzao-12. The contents of available nitrogen increased while available phosphorus decreased in rhizosphere soils in comparison with bulk soils. When compared to the open flooding irrigation, the film-covered trickle irrigation increased the activities of catalase, alkaline phosphatase, urease, and soil pH in both rhizosphere and bulk soils, the contents of available N and P in bulk soils and available K in rhizosphere soils, but decreased the activities of catalase and cellulose, and the contents of available N and P in rhizosphere soils as well as available K in bulk soils. Applying amino acid fertilizer can increase the activities of soil enzymes and the contents of available nutrients either in rhizosphere or bulk soils but decrease soil pH in rhizosphere soil when high dose of the fertilizer is used. In conclusion, agronomical practices such as fertilizer use and irrigation as well as crop variety can affect the soil biological and chemical properties, of which effects on crop growth and health need to be understood.