Effects of cover crop quality and quantity on nematode-based soil food webs and nutrient cycling
Effects of cover crop quality and quantity on nematode-based soil food webs and nutrient cycling
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DOI：
10.1016/j.apsoil.2008.10.004
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发表时间：
2009-02-01
影响因子：
4.8
通讯作者：
Van Horn, Mark
中科院分区：
文献类型：
--
作者：
DuPont, S. Tianna;Ferris, Howard;Van Horn, Mark
土壤食物网循环养分并调节寄生虫和病原体，这些服务对农业生产力和生态系统健康都是必不可少的。线虫为土壤食物网的动态变化提供了有用的指标。这项研究是为了确定保护性耕作系统中复盖作物组合是否能提高土壤线虫的食物网指标和作物产量。在加利福尼亚州戴维斯，研究了低、中、高C：N的3种覆盖作物处理(野豌豆/豌豆、燕麦/小麦和燕麦/小麦/豌豆/野豌豆)和裸露休耕对照的效应。对土壤线虫区系、土壤性质和植物生产力进行了测定。根据线虫群落的组成，计算土壤食物网指数，包括丰富度指数(EI)、结构指数(SI)、基本指数(BI)和渠道指数(CI)，以推断土壤食物网状况。覆盖番茄/玉米轮作的富集性机会细菌摄食线虫数量是休耕番茄/玉米轮作的两倍(机会细菌摄食者=163比98)，后者是氮矿化的积极参与者。在冬季，休耕地的食物网是基本的，在受干扰的、营养不良的条件下常见(BI=37)。机会性线虫总数、土壤NH4-N水平和推定的氮素矿化程度，在中低C：N比的覆盖作物处理中较高。杂食性和捕食性线虫稀少，在所有处理中平均少于6种线虫100g(-1)。第一年，休耕后植物生产力最高。相反，在第二年，氮素含量高的覆盖作物的生产力最高，而且生产力与土壤动物的结构显著相关。监测富集机会主义者的丰度可能会为管理者提供一种新的工具来评估土壤、食物网、氮矿化和植物生产力。(C)2008爱思唯尔B.V.保留所有权利。
Soil food webs cycle nutrients and regulate parasites and pathogens, services essential for both agricultural productivity and ecosystem health. Nematodes provide useful indicators of soil food web dynamics. This study was conducted to determine if nematode soil food web indicators and crop yield can be enhanced by combinations of cover crops in a conservation tillage system. The effects of three cover crop treatments (vetch/pea, oat/wheat and oat/wheat/pea/vetch) with low, medium and high C:N and a bare fallow control were investigated in Davis, CA. Nematode fauna, Soil Properties and plant productivity were measured. Soil food web indices, including the Enrichment index (EI), Structure Index (SI), Basal Index (BI), and Channel Index (CI), based on the composition of nematode assemblages, were calculated to infer soil food web condition. Cover cropped tomato/corn rotations had twice the number of enrichment opportunist bacterial feeding nematodes, active participants in nitrogen mineralization, than fallowed tomato/corn rotations (opportunist bacterial feeders = 163 versus 98). In winter fallowed plots food webs were basal, common in disturbed, nutrient-poor conditions (BI = 37). Total number of enrichment opportunist nematodes, soil NH4-N levels, and inferred nitrogen mineralization, were higher in cover crop treatments with low to mid C:N ratios. Omnivore and predator nematodes were scarce, averaging less than 6 nematodes 100 g(-1) in all treatments. in year one, plant productivity was highest after fallow. In contrast, in year two productivity was highest after cover crops with high nitrogen content and productivity significantly correlated with the structure of the soil fauna. Monitoring the abundance of enrichment opportunists may provide managers with a new tool to evaluate soil food web nitrogen mineralization and plant productivity. (C) 2008 Elsevier B.V. All rights reserved.