Soil aggregates indirectly influence litter carbon storage and release through soil pH in the highly alkaline soils of north China

PeerJ

article

Chao Yang¹  Jingjing Li¹  Yingjun Zhang¹ 

[1] College of Grassland Science and Technology, China Agricultural University;College of Grassland Science, Qingdao Agricultural University;Key Laboratory of Grassland Management and Rational Utilization, Ministry of Agriculture

关键词: Litter decomposition;    Soil aggregate-size classes;    Litter quality;    Soil pH;   

DOI  :  10.7717/peerj.7949

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Background Soil aggregate-size classes, structural units of soil, are the important factors regulating soil organic carbon (SOC) turnover. However, the processes of litter C mineralization and storage in different aggregates-size classes are poorly understood, especially in the highly alkaline soils of north China. Here, we ask how four different aggregate sizes influence rates of C release (Cr) and SOC storage (Cs) in response to three types of plant litter added to an un-grazed natural grassland. Methods Highly alkaline soil samples were separated into four dry aggregate classes of different sizes (2–4, 1–2, 0.25–1, and <0.25 mm). Three types of dry dead plant litter (leaf, stem, and all standing dead aboveground litter) of Leymus chinensis were added to each of the four aggregate class samples. Litter mass loss rate, Cr, and Cs were measured periodically during the 56-day incubation. Results The results showed that the mass loss in 1–2 mm aggregates was significantly greater than that in other size classes of soil aggregates on both day 28 and day 56. Macro-aggregates (1–2 mm) had the highest Cr of all treatments, whereas 0.25–1 mm aggregates had the lowest. In addition, a significant negative relationship was found between Cs/Cr and soil pH. After incubation for 28 and 56 days, the Cs was also highest in the 1–2 mm aggregates, which implied that the macro-aggregates had not only a higher CO2 release capacity, but also a greater litter C storage capacity than the micro-aggregates in the highly alkaline soils of north China.

【 授权许可】

CC BY