ABSTRACT

The purpose of this study was to examine the characteristics of four crop straw decayed products (SDPs) and their ameliorating effects on an acidic Ultisol. The straws of peanut, canola, rice and pea were decayed for 150 d to obtain decayed products. The Ultisol collected from Jiangxi province was incubated with these SDPs for 30 d. Then, soil pH and soil pH buffering capacity (pHBC) were measured and a simulated acidification experiment was carried out. The results showed that the SDPs had high pH and contained carbonate, organic anions and nutrients of N, P, Ca and Mg. Applying the SDPs increased not only soil pH but also soil pHBC, and thus the resistance of the soil to acidification significantly (p < 0.05). The pea straw decayed product showed the greatest effect on soil pHBC, followed by peanut straw decayed product. The incorporation of the SDPs slowed down soil acidification and reduced the concentration of soil soluble Al and decreased soil exchangeable Al during simulated soil acidification. Dissolution of carbonate and protonation of organic anions on the surface of solid organic matter were the main mechanisms for increasing soil pH and soil pHBC by the SDPs.

摘要

本研究的目的是检查四种农作物秸秆腐烂产品 (SDP) 的特性及其对酸性 Ultisol 的改善作用。花生、油菜、水稻、豌豆秸秆腐烂150 d，得到腐烂产物。从江西省收集的 Ultisol 与这些 SDP 孵育 30 天。然后，测量了土壤 pH 值和土壤 pH 缓冲能力（pHBC），并进行了模拟酸化实验。结果表明，SDPs 具有较高的 pH 值，含有碳酸盐、有机阴离子和 N、P、Ca 和 Mg 营养物质。施用 SDP 不仅增加了土壤 pH 值，还增加了土壤 pHBC，从而显着提高了土壤对酸化的抵抗力（p< 0.05)。豌豆秸秆腐烂产物对土壤pHBC的影响最大，其次是花生秸秆腐烂产物。在模拟土壤酸化过程中，SDP 的掺入减缓了土壤酸化并降低了土壤可溶性铝的浓度并降低了土壤可交换铝。固体有机质表面的碳酸盐溶解和有机阴离子质子化是 SDP 提高土壤 pH 值和土壤 pHBC 的主要机制。