Abstract

The distribution of decomposition products of corn and clover residues by density fractions of noncalcareous mantle loam was studied under controlled conditions. Two light (<1.4 g/cm³ (LF-1) and 1.4–2.2 g/cm³ (LF-2)) and heavy (>2.2 g/cm³ (HF)) fractions were isolated using sodium polytungstate. The LF-1 mainly consisted of incompletely decomposed plant residues; the LF-2, of their decomposition products bound with clay minerals (kaolinite, illite, smectites); and the HF, of the organic matter discretely sorbed on the surface of large grains of quartz and feldspars. It was demonstrated that during stabilization of newly formed organic matter (OM) by different density fractions, they are separated as a result of selective specific adsorption. In this case, the LF-2 is enriched in compounds that do not contain nitrogen, whereas the HF is enriched in nitrogen-containing compounds, including those of microbial nature. As a result, the C/N ratio decreases in the series: LF-1 > LF-2 > HF. The sizes of free and bound to mineral particles organic matter pools were calculated, and a scheme describing the mechanisms of stabilization of decomposition products of plant residues by organo-mineral fractions of different densities was suggested.

中文翻译：

---

壤土密度分数下植物残渣分解产物的稳定机理

摘要

在控制条件下，研究了非钙质地幔壤土的密度分数对玉米和三叶草残留物分解产物的分布。轻（<1.4 g / cm ³（LF-1）和1.4–2.2 g / cm ³（LF-2））和重（> 2.2 g / cm ³（HF））级分使用聚钨酸钠分离。LF-1主要由不完全分解的植物残渣组成。LF-2及其分解产物与粘土矿物（高岭石，伊利石，绿土）结合；和HF分别离散地吸附在石英和长石大颗粒表面上。结果表明，在通过不同的密度分数稳定新形成的有机物（OM）的过程中，由于选择性的特异性吸附，它们被分离了。在这种情况下，LF-2富含不含氮的化合物，而HF富含含氮化合物，包括微生物性质的化合物。结果，C / N比按以下顺序降低：LF-1＞ LF-2＞ HF。计算了自由的和与矿物颗粒结合的有机物库的大小，