作 者 ：佀国涵 赵书军 王瑞 徐大兵 秦兴成 谭军 向必坤 袁家富
期 刊 ：植物营养与肥料学报 2014年 20卷 4期 页码：905-912
Keywords:green manure, soil compactness, soil microorganism, soil enzyme activity,
摘 要 ：【目的】土壤的生物性状可作为评价土壤生态环境质量的指标，而土壤的物理性状对土壤的水、 肥、 气、 热等因素具有调控作用。绿肥是一种养分全面的优质生物肥源，翻压的绿肥种类以及绿肥和化肥的配施比例会影响土壤微生物的种群数量以及土壤酶活性，并对土壤的物理、 化学和生物性质以及生产力产生重要影响。本文研究连年翻压绿肥后土壤中微生物种群数量、 微生物量碳、 土壤酶的年际变化及其对植烟土壤团粒结构和土壤紧实度影响，旨在为烟区土壤改良和特色烟叶开发提供理论依据。【方法】利用3年田间定位试验，研究了连年翻压绿肥对植烟土壤物理及生物性状的影响； 将鲜土样过2 mm筛后，利用平板涂布法以及氯仿熏蒸培养法测定了连年翻压绿肥后土壤中细菌、 真菌和放线菌数量以及微生物量碳的含量； 将土样风干并过1 mm 筛后测定了土壤脲酶、 酸性磷酸酶以及过氧化氢酶的活性。土壤紧实度采用CP40Ⅱ数显式土壤紧实度仪对不同处理的土壤进行原位测定； 而土壤团聚体结构采用沙维诺夫法进行，采集的原状土样采用干筛法进行分级，然后计算出不同粒级团聚体的百分含量以及平均重量直径和几何平均直径。 【结果】连年翻压绿肥显著降低了10 cm土层处的土壤紧实度，且以翻压高量绿肥处理（30000 kg/hm2+85%化肥，GMH）的土壤紧实度最低，其土壤紧实度较常规施肥 (F) 和不施肥 (CK) 处理分别降低了25.4%和29.9%； 翻压绿肥增加了土壤中大于7 mm 的机械团聚体含量，但降低了小于1 mm 机械团聚体的含量。随着翻压绿肥年限的增加，翻压绿肥土壤中细菌、 真菌和放线菌的数量以及土壤微生物量碳均呈增加的趋势，翻压3 年绿肥后，GMH处理的土壤细菌、 真菌和放线菌的数量以及土壤微生物量碳含量较F处理分别提高了49.0%、 47.8%、 35.4%和40.7%； 与常规施肥相比，翻压低量绿肥 （15000 kg/hm2+85%化肥，GML）降低了土壤脲酶和过氧化氢酶的活性，但翻压高量绿肥能够恢复和提高其活性。【结论】连年翻压绿肥能够降低土壤紧实度，增强土壤团聚结构的稳定性，提高土壤中细菌、 真菌和放线菌的数量以及土壤微生物量碳的含量； 翻压高量的绿肥有利于土壤中脲酶、 过氧化氢酶和酸性磷酸酶活性的提高。
Abstract:【Objectives】Soil biological characteristic can be used as evaluation indexes for soil eco-environment quality, and soil physical characteristic can regulate soil water, fertilizer, gas and heat. Green manure has rich nutrients as a high-quality biological fertilizer, the variety of green manure, application ratio of green manure with chemical fertilizer will affect soil microbial population quantity and soil enzyme activity, which would affect soil physical, chemical and biological properties and soil productivity. In this study, an inter-annual variation of soil microbial population quantity, microbial biomass carbon and soil enzyme were investigated after consecutive overturning of green manure, and the effect of long-term overturning of green manure on soil granular structure and soil compaction was also studied to offer theoretical basis for soil amelioration and featured tobacco exploitation.【Methods】A consecutive 3-year field experiment was conducted to study effect of incorporating green manure on soil physical and biological characteristics. The fresh soil samples were sieved (less than 2 mm), and used for analysis on the quantity of bacteria, fungi and actinomycetes, and the content of microbial biomass carbon after consecutive overturning of green manure by dilution-plate method and chloroform fumigation culture method. Samples of air-dried soil were sieved (less than 1 mm) and subjected to analyze the activities of soil urease, acid phosphatase and catalase. Soil compaction was measured in situ by CP 40Ⅱ digital soil compactness instrument. Soil aggregate structure was analyzed by Xavier’s method, collective undisturbed soil were graded by dry sieve method. The content of different aggregate, mean weight diameter and geometric mean were calculated.【Results】The results showed that the consecutive overturn of green manure could remarkably reduces soil compactness in 10 cm soil layer, and the soil compactness in inputting high quantity of green manure treatment (GMH, 30000 kg/ha green manures+85% fertilizers) is the lowest. Compared with the conventional fertilization treatment (F) and no fertilization treatment (CK), the soil compactness in GMH treament is increased by 25.4% and 29.9%, respectively. The overturn of green manure could increase the content of more than 7 mm soil mechanical-stable aggregates and reduce the content of less than 1 mm soil mechanical-stable aggregates. With the increase of the returning age, the numbers of bacteria, fungi and actinomyces and the content of microbial biomass carbon are increased in incorporation green manure treatment. Compared with F treatment, the numbers of bacteria, fungi and actinomyces and the content of microbial biomass carbon in GMH treatment are respectively increased by 49.0%, 47.8%, 35.4% and 40.7% after 3-year consecutive overturn of green manure. The activities of soil urease, catalase and acid phosphatase in GMH treatment are increased year by year with the increase of the returning age. Compared with F treatment, the activities of urease and catalase are reduced in inputting low quantity of green manure treatment (GML, 15000 kg/ha green manures+85% fertilizers), but GMH treatment could restore and improve the activities of these enzymes.【Conclusions】The consecutive overturn of green manure could reduce soil compactness, and increase the numbers of bacteria, fungi and actinomyces and the content of microbial biomass carbon, and enhance stability of soil aggregate structure. It is benefit for improving activities of soil urease, acid phosphatase and catalase to input high quantity of green manure.
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