作 者 ：时鹏,高强,王淑平*,张妍
期 刊 ：生态学报 2010年 30卷 22期 页码：6173~6182
关键词：玉米连作；秸秆还田；施肥；微生物功能多样性；Biolog；
Keywords:continuous cropping of corn, straw return, fertilization, microbial community functional diversity, Biolog,
摘 要 ：采用Biolog技术，借助吉林农业大学1984年建立的长期定位试验，以撂荒和非玉米连作（当季作物为芸豆）为对照，研究玉米连作及其不同施肥措施对土壤微生物功能多样性的影响。结果表明，反映土壤微生物活性的平均颜色变化率（AWCD）呈现出以下变化规律：撂荒(UC)>非玉米连作(NCC)>玉米连作不施肥(CK)；玉米连作配施秸秆(S、SN、SNPK)>玉米连作配施NPK(NPK)>玉米连作不施肥(CK)>玉米连作单施N(N)。微生物培养72h活性旺盛，各处理AWCD在0.395—0.732之间，其中撂荒AWCD显著高于非玉米连作和玉米连作不施肥（P<0.05）；玉米连作配施秸秆明显提高微生物活性，玉米连作配施秸秆(S、SN、SNPK) AWCD是玉米连作不施肥和单施化肥（N、NPK）的1.26—1.62倍。玉米连作不施肥土壤微生物群落多样性指数（H、E、S）低于撂荒处理，但高于非玉米连作处理，非玉米连作提高了土壤微生物优势度指数。玉米连作配施秸秆土壤微生物物种丰富度指数和均匀度指数高于玉米连作不施肥和玉米连作施化肥，玉米连作单施氮肥优势度指数较高，其它多样性指数降低。主成分分析结果表明，不同处理土壤微生物碳源利用特征出现分异：撂荒和玉米连作配施秸秆处理集中在第1主成分正方向，得分系数在2.39—4.17之间，土壤微生物碳源利用特征相似；玉米连作不施肥、玉米连作单施化肥和非玉米连作处理分布在第1主成分负方向，得分系数在-5.43—-1.59之间。土壤微生物利用的碳源主要是糖类、羧酸类、氨基酸和聚合物。玉米连作配施秸秆和撂荒有利于提高土壤微生物代谢活性和土壤微生物群落功能多样性，玉米连作单施化肥尤其单施氮肥土壤微生物活性和功能多样性下降。
Abstract:The characteristics of soil microbes are sensitive indicators of soil fertility. Fertilization can influence soil physiochemical and biological properties. The impact of continuous cropping of corn on a soil ecosystem is a gradual process. Consequently, it is important to understand the effect of continuous cropping of corn and fertilization on soil microbial community functional diversity. In this study uncultivated (UC) and non-continuous cropping (NCC) were set as controls and treatments were continuous cropping of corn with different fertilization: application of straw (S), combined application of straw and N (SN), combined application of straw and NPK (SNPK), application of N (N), application of NPK (NPK), and no fertilizer (CK). Soil microbial community functional diversity was studied using Biolog ECO plates. The Average Well Color Development (AWCD) indicated the activity of the soil microbial community. The indices of Shannon index (H), Substrate evenness (E), Simpson′s Dominance (Ds) and Substrate richness (S) were calculated to show the soil microbial community diversity. Substrates in Biolog ECO plates were divided into 6 groups: Carbohydrates, Carboxylic acids, Amino acids, Amines, Polymers and Miscellaneous. Principal component analysis was used to show the difference utilization of substrates by soil microbes. The results indicated that AWCD changed with the incubation progress of different treatments in the following order: UC> NCC> CK; continuous cropping of corn with straw return (S, SN and SNPK)> NPK>CK> N. The activity of microbe was vigorous at the time of cultivation of 72 h and AWCD of treatments were range from 0.395 to 0.732. AWCD of UC was higher than CK and NCC. Continuous cropping of corn with straw return (S, SN and SNPK) significantly increased soil microbial activity and they were 1.26 to 1.62 times higher than continuous cropping of corn with fertilizer (N and NPK) and CK. UC and continuous cropping of corn with straw return (S, SN and SNPK) significantly increased the Shannon index (H) and Substrate evenness (E), while continuous cropping of corn with chemical fertilizer (N and NPK) decreased these microbial diversity indices (P<0.05). CK had lower microbial diversity indices (H, E and S) than UC, but they were higher than indices of NCC. NCC had larger Ds than other treatments because nitrogen-fixing microorganisms grew vigorously supported by the legume crop. Principal component analysis showed that carbon utilization by soil microbial communities changed in different treatments. However, UC and continuous cropping of corn with straw return (S, SN, SNPK) had similar carbon utilization. The treatments of UC, S, SN and SNPK concentrated in the positive direction of the first principal component and the score coefficients ranged from 2.39 to 4.17. Conversely, the treatments of CK, N, NPK and NCC concentrated in the negative direction of the second principal component and the score coefficients ranged from -5.43 to -1.59. The carbon sources mostly used by soil microbes were Carbohydrates, Amino acids, Carboxylic acids and Polymers. Therefore, uncultivated and continuous cropping of corn with straw return preserved soil quality well and improved the activity and functional diversity of the soil microbial community. Continuous cropping of corn with chemical fertilizer especially nitrogen fertilizer decreased soil microbial community functional diversity.
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