National Engineering Laboratory for Improving Quality of Arable Land, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Department of Agronomy, The University of Haripur, Haripur 22620, Pakistan.
Chemosphere. 2021 Mar;267:128897. doi: 10.1016/j.chemosphere.2020.128897. Epub 2020 Nov 11.
Crop productivity and soil health are limited by organic carbon (OC), however, the variations in the mechanisms of SOC preservation in a complete soil profile subjected to long-term fertilization remains unclear. The objective of the study was to examined the content and profile distribution of the distinctive SOC protection mechanisms on a complete profile (0-100 cm) of Eumorthic Anthrosols in Northwest China after 23 years of chemical and manure fertilization. The soil was fractionated by combined physical-chemical and density floatation techniques. Throughout the profile, significant variations were observed among fractions. In the topsoil (0-20 and 20-40 cm), mineral coupling with the fertilization of manure (MNPK) enhanced total SOC content and recorded for 29% of SOC in the 0-20 and 20-40 cm layers. Moreover, MNPK increased the SOC content of the unprotected cPOC fraction by 60.9% and 61.5% in the 0-20 and 20-40 cm layer, while SOC content was low in the subsoil layers (40-60, 60-80 and 80-100 cm, respectively) compared with the control (C). The highest OC under MNPK in physically protected micro-aggregates (μagg) (6.36 and 6.06 g C kg), and occluded particulate organic carbon (iPOC) (1.41 and 1.29 g C kg) was found in the topsoil layers. The unprotected cPOC fraction was the greatest C accumulating fraction in the topsoil layers, followed by μagg and H-μSilt fractions in the soil profile, implying that these fractions were the most sensitive to the fertilization treatments. Overall, the unprotected, physically protected, and physico-chemically protected fractions were the dominant fractions for the sequestration of carbon across fertilization treatments and soil layers.
作物生产力和土壤健康受到有机碳（OC）的限制，然而，长期施肥条件下完整土壤剖面中 SOC 保护机制的变化仍不清楚。本研究的目的是在经过 23 年的化肥和有机肥施肥后，研究中国西北地区 Eumorthic Anthrosols 完整剖面（0-100 cm）中独特的 SOC 保护机制的含量和剖面分布。采用物理化学结合密度浮选技术对土壤进行分级。整个剖面中，各部分之间存在显著差异。在表土（0-20 和 20-40 cm）中，有机肥配施化肥（MNPK）与矿物结合，增加了总 SOC 含量，在 0-20 和 20-40 cm 层中分别占 SOC 的 29%。此外，MNPK 增加了未受保护的 cPOC 部分在 0-20 和 20-40 cm 层中的 SOC 含量，分别为 60.9%和 61.5%，而亚土层（40-60、60-80 和 80-100 cm）的 SOC 含量较低，与对照（C）相比。MNPK 下物理保护的微团聚体（μagg）（6.36 和 6.06 g C kg）和包封颗粒有机碳（iPOC）（1.41 和 1.29 g C kg）中的 OC 最高，在表土层。未受保护的 cPOC 部分是表土层中最大的 C 积累部分，其次是 μagg 和 H-μSilt 部分，这意味着这些部分对施肥处理最敏感。总的来说，未受保护的、物理保护的和物理化学保护的部分是碳在不同施肥处理和土壤层中固定的主要部分。
