Rapid intrinsic rates of amino acid biodegradation in soils are unaffected by agricultural management strategy
Rapid intrinsic rates of amino acid biodegradation in soils are unaffected by agricultural management strategy
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DOI：
10.1016/j.soilbio.2004.11.023
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发表时间：
2005-07-01
影响因子：
9.7
通讯作者：
Edwards, AC
中科院分区：
文献类型：
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作者：
Jones, DL;Kemmitt, SJ;Edwards, AC
氨基酸是土壤中溶解有机氮的最大输入源之一，因此它们构成了有机氮循环的主要组成部分。然而，农业管理对土壤中氨基酸周转率的影响在很大程度上仍然未知。本研究的目的是在长期的田间试验中，肥料添加（N，P和K），放牧，pH值的操作（石灰添加），植被覆盖和转移（草地与耕地）和排水的C-14标记的氨基酸在农业表土矿化的影响进行评估。我们的研究结果表明，氨基酸矿化的内在速率是快速的所有管理制度，无论测试的土壤类型。所有土壤（n = 155）中氨基酸的平均（+/- SEM）半衰期计算为2.3 +/- 0.5 h。分配到呼吸（总C的25%）与生物量生产（总C的75%）的氨基酸-C的相对量也不受管理策略。氨基酸矿化率被证明是轻微敏感的土壤pH值，峰值在pH值（（氯化钙））5.0左右，在pH值的极端（pH值3.8和6.4）约两倍减少。我们的结论是，管理制度对农业土壤中氨基酸矿化的内在速率影响不大。因此，我们建议，总的微生物活性，而不是微生物多样性或社区结构可能是农业土壤中氨基酸周转的关键决定因素。(c)2005爱思唯尔有限公司保留所有权利。
Amino acids represent one of the largest inputs of dissolved organic nitrogen to soil and consequently they constitute a major component of the organic N cycle. The effect of agricultural management on the rate of amino acid turnover in soil, however, remains largely unknown. The aim of this study was to evaluate in long-term field experiments the effect of fertilizer addition (N, P and K), grazing, pH manipulation (lime addition), vegetation cover and shifts (grassland versus arable) and drainage on the mineralization of C-14-labelled amino acids in agricultural topsoils. Our results showed that the intrinsic rate of amino acid mineralization was rapid for all management regimes, irrespective of the tested soil type. The average (+/- SEM) half-life of the amino acids in all soils (n = 155) was calculated to be 2.3 +/- 0.5 h. The relative amount of amino acid-C partitioned into respiration (25% of total C) versus biomass production (75% of total C) was also unaffected by management strategy. The rate of amino acid mineralization was shown to be slightly sensitive to soil pH, peaking at around pH((CaCl2)) 5.0 with an approximate twofold reduction at the pH extremes (pH 3.8 and 6.4). We conclude that management regime has little effect on the intrinsic rate of amino acid mineralization in agricultural soils. We propose therefore that total microbial activity rather than microbial diversity or community structure is likely to be the key determinant governing amino acid turnover in agricultural soils. (c) 2005 Elsevier Ltd. All rights reserved.