Effects and fate of biochar from rice residues in rice-based systems
Effects and fate of biochar from rice residues in rice-based systems
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DOI：
10.1016/j.fcr.2011.01.014
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发表时间：
2011-04-03
影响因子：
5.8
通讯作者：
Knoblauch, C.
中科院分区：
文献类型：
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作者：
Haefele, S. M.;Konboon, Y.;Knoblauch, C.
虽然作物残留物构成了巨大的资源，但在以水稻为基础的系统中，实际的残留物管理做法具有各种负面影响，并有助于全球变暖。结合生物能源/生物炭系统的概念可以以一种新的方式解决这些问题。水稻秸秆将用于能源生产，从而减少田间燃烧和化石燃料的使用，而生物炭副产品可以帮助改善土壤，避免甲烷排放，并将碳封存在土壤中。为了检验其中的一些前景，我们从2005年到2008年在三种不同的水稻生产系统中进行了田间试验。目的研究稻壳生物炭对土壤特性的影响，评价稻壳炭在不同体系下的稳定性，并评价生物炭施用的农艺效应。结果表明，施用未处理稻壳和炭化稻壳增加了土壤总有机碳、土壤全氮、碳氮比、速效磷和速效钾，对土壤反应性、交换性Ca、Mg、Na和CEC的影响不显著或不显著。在肥沃的土壤上，CRH的高碳氮比似乎限制了氮的有效性，从而在施用后的前三个季节略微降低了粮食产量。在贫瘠的土壤上，作物也遭受了水分胁迫，土壤化学和物理改良使产量增加了16-35%。再加上一项平行研究，包括在一个地点测量甲烷和二氧化碳排放，结果强烈表明，CRH在各种水稻土壤和系统中非常稳定，可能持续数千年。然而，该研究还表明，CRH在某些土壤中具有很强的流动性。特别是在贫瘠的沙质土壤中，施用的碳在施用后的4年内约有一半在土壤剖面中移动到0.30 m以下。我们得出的结论是，水稻残基生物炭在水稻系统中可能是有益的，但对土壤肥力、粮食产量和土壤有机碳的实际影响将取决于特定地点的条件。在田间试验中对生物炭进行长期研究似乎对更好地了解生物炭的效应和研究其在土壤中的行为至关重要。(C) 2011 Elsevier B.V.版权所有
Although crop residues constitute an enormous resource, actual residue management practices in rice-based systems have various negative side effects and contribute to global warming. The concept of a combined bioenergy/biochar system could tackle these problems in a new way. Rice residues would be used for energy production, thereby reducing field burning and the use of fossil fuels, and the biochar by-product could help to improve soils, avoid methane emissions, and sequester carbon in soils. To examine some of these promises, we conducted field experiments from 2005 to 2008 in three different rice production systems. Objectives were to study the effect of biochar from rice husks on soil characteristics, assess the stability of carbonized rice residues in these different systems, and evaluate the agronomic effect of biochar applications. The results showed that application of untreated and carbonized rice husks (RH and CRH) increased total organic carbon, total soil N. the C/N ratio, and available P and K. Not significant or small effects were observed for soil reaction, exchangeable Ca, Mg, Na, and the CEC. On a fertile soil, the high C/N ratio of CRH seemed to have limited N availability, thereby slightly reducing grain yields in the first three seasons after application. On a poor soil, where the crop also suffered from water stress, soil chemical and physical improvements increased yields by 16-35%. Together with a parallel study including methane and CO2 emission measurements at one site, the results strongly suggest that CRH is very stable in various rice soils and systems, possibly for thousands of years. However, the study also showed that CRH was very mobile in some soils. Especially in poor sandy soil, about half of the applied carbon seemed to have moved below 0.30 m in the soil profile within 4 years after application. We concluded that biochar from rice residues can be beneficial in rice-based systems but that actual effects on soil fertility, grain yield, and soil organic carbon will depend on site-specific conditions. Long-term studies on biochar in field trials seem essential to better understand biochar effects and to investigate its behavior in soils. (C) 2011 Elsevier B.V. All rights reserved.