Nutrient availability limits carbon sequestration in arable soils
Nutrient availability limits carbon sequestration in arable soils
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DOI：
10.1016/j.soilbio.2013.09.032
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发表时间：
2014-01-01
影响因子：
9.7
通讯作者：
Kirkegaard, John A.
中科院分区：
文献类型：
--
作者：
Kirkby, Clive A.;Richardson, Alan E.;Kirkegaard, John A.
土壤是全球陆地碳（C）的最大储存库。从自然生态系统到农业生态系统的转换通常会导致土壤有机碳（SOC，高达50%或类似于30-40吨公顷（-1））的显著损失，“恢复”这种损失的C是一个重大的全球挑战。土壤有机质（SOM）中最稳定的组分，以下简称为细组分SOM（FF-SOM），不仅含有碳、氢（H）和氧（O），而且含有大量的氮（N）、磷（P）和硫（S），其比例大致恒定。这些相关营养物质的可用性是形成FF-SOM的必要条件。在这里，我们表明，在短期内（56天）的培养实验与C-13标记的小麦秸秆添加到四个不同的粘土含量的土壤中，秸秆转化为“新的”FF-SOM增加了三倍，通过增加残留物与补充养分。我们还表明，“老”预先存在的FF-SOM的损失增加秸秆添加，相比，没有秸秆添加的土壤，但这种损失得到改善，营养素添加在我们的两个土壤。这一发现可以说明为什么在一些生产性农业土壤中SOC的积累往往比返回到它们的富含C的残留物的量所预期的要少得多，因为最佳的C螯合需要额外的营养物质，这些营养物质单独用于作物生产。此外，它提供了更好的理解土壤中的碳周转的短期动态，并在长期内，可能有重要的影响，旨在增加土壤固碳，以恢复肥力和帮助缓解气候变化的全球战略。(C)2013爱思唯尔有限公司保留所有权利。
Soils are the largest reservoir of global terrestrial carbon (C). Conversion from natural to agricultural ecosystems has generally resulted in a significant loss of soil organic-C (SOC, up to 50% or similar to 30-40 t ha(-1)) and 'restoring' this lost C is a significant global challenge. The most stable component of soil organic matter (SOM), hereafter referred to as fine fraction SOM (FF-SOM), contains not only C, hydrogen (H) and oxygen (O), but substantial amounts of nitrogen (N), phosphorus (P) and sulphur (S), in approximately constant ratios. The availability of these associated nutrients is essential for the formation of FF-SOM. Here we show, in short term (56 day) incubation experiments with C-13 labelled wheaten straw added to four soils with differing clay content, that conversion of straw into "new" FF-SOM is increased by up to three-fold by augmenting the residues with supplementary nutrients. We also show that the loss of "old" pre-existing FF-SOM increased with straw addition, compared to soils with no straw addition, but that this loss was ameliorated by nutrient addition in two of our soils. This finding may illuminate why the build-up of SOC in some productive agricultural soils is often much less than expected from the amounts of C-rich residues returned to them because optimum C sequestration requires additional nutrients above that required for crop production alone. Moreover, it provides greater understanding of short-term dynamics of C turnover in soil, and in the longer term, may have important implications for global strategies aimed at increasing soil C sequestration to restore fertility and help mitigate climate change. (C) 2013 Elsevier Ltd. All rights reserved.