Effects of biochars generated from crop residues on chemical properties of acid soils from tropical and subtropical China
Jin-Hua Yuan and Ren-Kou Xu
Soil Research 50(7): 570-578.
http://dx.doi.org-10.1071-SR12118
Abstract. The chemical compositions of biochars from ten crop residues generated at 3508C and their effects on chemical properties of acid soils from tropical and subtropical China were investigated. There was greater alkalinity and contents of base cations in the biochars from legume residues than from non-legume residues. Carbonates and organic anions of carboxyl and phenolic groups were the main forms of alkalis in the biochars and their relative contributions to biochar 5 alkalinity varied with crop residues. Incubation experiments indicated that biochar incorporation increased soil pH and soil exchangeable base cations and decreased soil exchangeable acidity. There were greater increases in soil pH and soil exchangeable base cations and a greater decrease in soil exchangeable acidity for biochars from legume than from nonlegume residues. The biochars did not increase the cation exchange capacity (CEC) of soils with relatively high initial CEC but did increase the CEC of soils with relatively low initial CEC at an addition level of 1%. The incorporation of biochars 10 from crop residues not only corrected soil acidity but also increased contents of potassium magnesium and calcium in these acid soils from tropical and subtropical regions and thus improved soil fertility.
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农业废弃物制备的生物质炭对中国热带和亚热带地区酸性土壤化学性质的影响
袁金华，徐仁扣
Soil Research 50(7): 570-578.
http://dx.doi.org-10.1071-SR12118
摘要：选择10种农业废弃物，于350℃下制备了相应的生物质炭，对生物质炭的化学组成进行了表征，考察了10种生物质炭对中国热带和亚热带地区酸性土壤化学性质的影响。研究结果表明，豆科物料来源的生物质炭的碱性和盐基阳离子的含量要高于非豆科物料来源的生物质炭。碳酸盐和有机阴离子(羰基和酚羟基)是生物质炭中碱性物质的主要存在形态，它们对生物质炭碱性的贡献随物料种类的不同而不同。室内培养实验表明，10种生物质炭均能提高土壤的pH值、增加土壤的交换性盐基阳离子含量，同时降低土壤交换性酸含量。豆科物料来源的生物质炭对土壤pH值和交换性盐基阳离子含量的提高幅度及对土壤交换性酸的降低幅度均大于非豆科物料来源的生物质炭。对于阳离子交换量(CEC)较高的土壤，添加1%的生物质炭不能提高土壤的CEC；但对CEC较低的土壤，生物质炭可以显著提高土壤的CEC。农业废弃物制备的生物质炭不仅可以改良热带和亚热带地区酸性土壤的酸度，而且可以提高土壤中钾、钙和镁等元素的含量，改善土壤肥力水平。