MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
Max Planck Institute for Biogeochemistry, Jena 07745, Germany.
Sci Total Environ. 2022 Sep 10;838(Pt 1):155892. doi: 10.1016/j.scitotenv.2022.155892. Epub 2022 May 13.
Dissolved organic matter (DOM) is an active component of organic manure that is widely used in agroecosystems to increase nutrient availability and consequently enhance crop yields. However, the ways in which soil DOM characteristics are influenced by organic manure and how it contributes to crop yield and soil P availability remains unclear. Here, we conducted a 5-year field experiment and demonstrated that partial replacement of chemical P fertilizer with swine manure could maintain high rice yield and soil available P levels and increase P fertilizer use efficiency (PUE) in comparison to chemical fertilization, even when the total P input was reduced. This suggests that organic manure application can significantly mobilize soil P and increase P availability. Structural equation modeling analysis indicated that the soil pH and humification degree of DOM, rather than DOM content, directly decreased maximum P adsorption capacity. The combined results of the optical spectroscopy and ultrahigh-resolution mass spectroscopy obtained from the laboratory validation experiment based on the DOM-removed soil demonstrated that manure-derived DOM competing with P for adsorption was one of the main reasons for the increase in soil P availability and that the effective DOM components were N-containing lignins, tannins, and condensed polycyclic aromatics with higher O/C and lower H/C ratios. Overall, our results provide solid evidence that soil DOM characteristics are influenced by manure application and facilitate soil P availability, which could help guide the sustainable P management and manure application in agroecosystems.
溶解有机质（DOM）是有机肥料中的一种活性成分，广泛应用于农业生态系统中，以增加养分的有效性，从而提高作物产量。然而，土壤 DOM 特性受有机肥料影响的方式以及它如何促进作物产量和土壤磷有效性仍不清楚。在这里，我们进行了一项为期 5 年的田间试验，结果表明，与化学施肥相比，用猪粪部分替代化学磷肥可以维持高水稻产量和土壤有效磷水平，并提高磷肥料利用率（PUE），即使总磷投入减少。这表明有机肥料的施用可以显著提高土壤磷的有效性。结构方程模型分析表明，土壤 pH 值和 DOM 的腐殖化程度，而不是 DOM 含量，直接降低了最大磷吸附容量。基于去除 DOM 的土壤进行的实验室验证实验的光学光谱和超高分辨率质谱的综合结果表明，源自粪肥的 DOM 与磷竞争吸附是增加土壤磷有效性的主要原因之一，而有效的 DOM 组成部分是含氮木质素、单宁和缩合多环芳烃，具有较高的 O/C 比和较低的 H/C 比。总的来说，我们的研究结果为土壤 DOM 特性受粪肥施用影响并促进土壤磷有效性提供了确凿的证据，这有助于指导农业生态系统中磷的可持续管理和粪肥的施用。
