轮作连作荞麦田主要微生物类群及土壤酶活性变化

为探明荞麦不同连作和轮作模式对土壤环境的影响,在连续4年定位试验基础上,通过平板涂布计数法和比色法,研究隔年作、轮作和连作荞麦生育期间土壤微生物数量、酶活性与土壤肥力的变化。结果表明:土壤微生物总数随着荞麦生育进程的推进而增加,尤其是荞麦连作田土壤微生物——细菌,开花期至灌浆期增长显著,并于灌浆期达到轮作细菌数的4.3倍。土壤酶活性连作总体偏高,脲酶、碱性磷酸酶表现尤为明显,均高于隔年作和轮作,且达到1%极显著水平。连作土壤碱性磷酸酶、蔗糖酶活性与细菌呈显著正相关;脲酶、过氧化氢酶活性则与土壤微生物数量之间无显著相关关系。由此,荞麦短期连作下表现出的B/F(细菌+放线菌)/真菌]比值更大,土壤脲酶、碱性磷酸酶活性更强,说明短期连作较利于荞麦田土壤理化性质的改善。

Changes of main microbial strains and enzymes activities in buckwheat rotation and continuous cropping soil

To study the effect of buckwheat continuous cropping and rotation on soil environment,a series of experiments about the changes of soil microorganism,soil enzyme activities and soil fertility,were conducted on the basis of 4 years location test,with spread-plate method and colorimetric method.The results show that the total number of soil microorganisms increases with the advance of buckwheat''s growing period.Taking the bacteria of the continuous cropping for example,the number increases significantly from blooming stage to milking stage,reaching 4.3 times of the rotation bacteria in milking stage.The soil enzyme activities of continuous cropping stay higher than other two cropping patterns,especially for the urease and alkaline phosphatase(ALP) with a significant level of 1%.The phosphatase and sucrase of continuous cropping have a significant positive correlation with bacteria.However,there is no significant correlation between urease,catalase and soil microorganism.Thus,the B/F of buckwheat has a larger ratio under short-term continuous cropping,the soil enzyme activities of urease and alkaline phosphatase are stronger,show that short-term continuous cropping is beneficial to the soil physical and chemical properties of buckwheat.