水稻土中脲酶产生菌、脲酶活性及尿素利用率
Studies on Urease-producing Microorganisms, Urease Activity and Urea Efficiency in Paddy Soil
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摘要: 本文研究结果表明,水稻土中的脲酶产生菌的数量,无论是不同季节,不同类型的水稻土,还是土壤层次的分布上与其相应的土壤脲酶活性高低相一致。细菌、放线菌、真菌三种类型菌种中,其脲酶产生菌所占的比例分别为:32.5—82.5%、50.0—83.0%和65.0—95.0%,但脲酶活性高的脲酶产生菌为数不多,脲酶活性为2.0mgNH3-N/g·Protein·24hr·37℃以下的菌株所占比例较大。尿素球肥深施和尿索球肥深施加红萍与尿素表施或尿素表施加红萍比较,可以降低水稻土中的脲酶活性,提高尿素利用率。Abstract: The investigation showed that the numbers of urease-producing microorganisms were identical with the urease activities in responding paddy soils whatever different seasons,soil type and the distribution of soil profile.The proportions of urease-producing populations among bacteria,actinomyces and fungi account for 32.5-85.5%,50-83% and 65-95% respectively.However,few of them showed high urease activity,and mostly were below 2.0 NH3-N mg/g· Protein·24hr · 37℃ To compare with the treatments of urea topdreasing and urea topdressing with azolla application,the urease activities in paddy soils of the treatments of deepplacement of urea ball fertilizer,and deepplacement of urea ball fertilizer with azolla were decreased.As a result,the urea efficiency was increased.