Decomposition and mineralization of energy crop residues governed by earthworms
Decomposition and mineralization of energy crop residues governed by earthworms
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DOI：
10.1016/j.soilbio.2009.04.015
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发表时间：
2009-07-01
影响因子：
9.7
通讯作者：
Emmerling, Christoph
中科院分区：
文献类型：
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作者：
Ernst, Gregor;Henseler, Isabell;Emmerling, Christoph
能源作物越来越多地在世界各地的农业管理系统中种植。用能源作物替代粮食作物（如谷物），由于其结构和化学组成不同，一般可能改变土壤中的生物活性和凋落物分解，从而改变土壤功能。进行了土壤微宇宙实验，以评估不同的能源作物残留物在土壤中的分解和微生物矿化相比，粮食作物，有或没有蚯蚓。将能源作物冬油菜（Brassica napus）、玉米（Zea mays）、芒草（Miscanthus acetateus）和粮食作物燕麦（Avena sativa）的残留物各自作为食物源提供给混合的蚯蚓种群，每个种群由一个个体的蚯蚓、Aporrectodea coliginosa和Octolabacterium tyrtaeum组成。6周后，测定土壤表面枯枝落叶流失率、蚯蚓生物量、微生物生物量-C和A微生物活性以及酶活性。结果强调，凋落物损失和微生物参数主要是由蚯蚓促进的，另外还受到不同凋落物的结构和化学组成的影响。蚯蚓对凋落物的分解以富氮玉米凋落物处理最高（碳氮比34.8），芒草凋落物最低（碳氮比134.4）。结果表明，与其他凋落物类型相比，有玉米凋落物的土壤微生物生物量和基础呼吸量较高。土壤中微生物菌群与氮素的比值随蚯蚓的存在而增加，说明蚯蚓与微生物之间存在氮素竞争。此外，酶活性对不同类型的凋落物和土壤活性的反应也不同。当提供高碳氮比的凋落物作为食物来源时，蚯蚓的存在降低了参与N循环的酶，而参与C循环的酶则趋于增加。特别是在芒草处理，较少的N可能会保留酶降解，表明蚯蚓和微生物之间的N竞争可能会有所不同的凋落物类型。特别是，芒在农业管理系统中的扩展可能会导致土壤中微生物活性降低和微生物氮素亏缺增加。(C)2009爱思唯尔有限公司保留所有权利。
Energy crops are increasingly cultivated in agricultural management systems world-wide. A substitution of food crops (e.g. cereals) by energy crops may generally alter the biological activity and litter decomposition in soil due to their varying structural and chemical composition and subsequently modify soil functioning. A soil microcosm experiment was performed to assess the decomposition and microbial mineralization of different energy crop residues in soil compared to a food crop, with or without earthworms. Residues of the energy crops winter rape (Brassica napus), maize (Zea mays), miscanthus (Miscanthus giganteus) and the food crop oat (Avena sativa) were each provided as food source for a mixed earthworm population, each consisting of one individual of Lumbricus terrestris, Aporrectodea coliginosa, and Octolasion tyrtaeum. After 6 weeks, the rate of litter loss from the soil surface, earthworm biomass, microbial biomass-C and A microbial activity, and enzyme activities were determined. The results emphasized, that litter loss and microbial parameters were predominantly promoted by earthworms and were additionally influenced by the varying structural and chemical composition of the different litter. Litter decay by earthworms was highest in N-rich maize litter treatment (C-N ratio 34.8) and lowest in the case of miscanthus litter (C-N ratio 134.4). As a consequence, the microbial biomass and basal respiration in soils with maize litter were higher, relative to other litter types. MBC-MBN ratio in soil increased when earthworms were present, indicating N competition between earthworms and microorganisms. Furthermore, enzyme activities responded in different ways on the varying types of litter and earthworm activity. Enzymes involved in the N-cycle decreased and those involved in the C-cycle tended to increase in the presence of earthworms, when litter with high C-N ratio was provided as a food source. Especially in the miscanthus treatments, less N might remain for enzymatic degradation, indicating that N competition between earthworms and microorganisms may vary between different litter types. Especially, an expansion of miscanthus in agricultural management systems might result in a reduced microbial activity and a higher N deficit for microorganisms in soil. (C) 2009 Elsevier Ltd. All rights reserved.