Soil microbial communities and enzyme activities in a reclaimed coastal soil chronosequence under rice-barley cropping
Soil microbial communities and enzyme activities in a reclaimed coastal soil chronosequence under rice-barley cropping
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DOI：
10.1007/s11368-012-0544-7
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发表时间：
2012-08-01
影响因子：
3.6
通讯作者：
Wang, Hailong
中科院分区：
文献类型：
--
作者：
Fu, Qinglin;Liu, Chen;Wang, Hailong
采用水稻-大麦复垦时间顺序进行了滨海盐碱地土壤酶活性和微生物学研究。本研究旨在探讨复垦后土壤pH、电导率（EC）和有机碳（SOC）的变化是否会直接影响土壤酶活性和微生物群落结构的变化。研究区域位于中国东南部。分别于1976年、1984年、1996年和2006年开垦了4个试验点，每个试验点分为3个地块，每个地块面积为22 m × 10 m。每年，这些地块夏季种植水稻（cv秀水），冬季种植大麦（cv延麦）。土壤pH和EC在土壤与水比例为1:5的水悬浮液中测定。采用重铬酸盐加热氧化法测定土壤有机碳含量。测定的土壤酶活性包括过氧化氢酶、脲酶和蛋白酶。采用变性梯度凝胶电泳法测定土壤微生物群落结构。水稻-大麦复垦降低了土壤EC和pH值，但增加了土壤有机碳、过氧化氢酶、脲酶和蛋白酶活性以及细菌、放线菌和真菌的细胞数量，导致细菌群落多样性增加。酶活性和细菌群落多样性与土壤有机碳呈极显著正相关，与pH、EC呈极显著负相关。在1996年以前复垦的土壤中没有出现与咸水有关的Gaetbulibacter、Sporosarcina、Flavobacterium、Aequorivita和Gillisia有关的5个细菌类群。本研究结果表明，影响微生物活性的土壤性质（如EC、pH和SOC）显著影响过氧化氢酶、脲酶和蛋白酶的活性以及微生物群落组成。稻麦复垦10多年后，土壤中EC减少，海洋和盐碱化环境中常见的细菌也消失了。
A field experiment with a reclamation chronosequence under rice-barley cropping was conducted to investigate soil enzyme activities and microbiology in a coastal saline soil. The aim of this study was to test whether changes in enzyme activity and microbial community structure are directly impacted by changes in soil pH, electrical conductivity (EC), and organic carbon (SOC) due to reclamation.The research area is located in south-eastern China. Four experimental sites were reclaimed in 1976, 1984, 1996, and 2006, respectively, and each site was divided into three plots, each of which was 22 m x 10 m. Each year, the plots were planted with rice (cv Xiushui) in summer and barley (cv Yanmai) in winter. Soil pH and EC were determined in an aqueous suspension with a 1:5 ratio of soil and water. Soil organic carbon content was measured by dichromate oxidation with heating. Measured soil enzyme activities included catalase, urease, and protease. Soil microbial community structures were assessed using denaturing gradient gel electrophoresis.Reclamation under rice-barley cropping reduced EC and pH, but increased SOC, the activities of catalase, urease and protease, and the cell numbers of bacteria, actinomycetes, and fungi, resulting in an increase in the bacterial community diversity. The enzyme activities and bacterial community diversity were significantly positively correlated with SOC, and negatively correlated with pH and EC. Five bacterial groups related to Gaetbulibacter, Sporosarcina, Flavobacterium, Aequorivita, and Gillisia, which have been associated with saline waters, did not appear in the soils that had been reclaimed prior to 1996.Results of this field study suggest that soil properties which affect microbial activity such as EC, pH, and SOC significantly influence the activities of catalase, urease, and protease, and microbial community composition. More than 10 years after reclamation under rice-barley cropping, EC had decreased and bacteria typically found in marine and saline environments had disappeared from the soil.