Abstract
Revealing the variation in soil aggregate-associated organic carbon (Corg) in tea plantations of various planting ages is crucial to shed more light on the accumulation and decomposition of soil Corg in the tea-planting period. This study measured the concentrations of soil Corg, active carbon (Cact), and recalcitrant carbon (Crec) in different-sized aggregates obtained from tea plantations of various planting ages (8, 17, 25, and 43 years old) at the soil depths of 0–20 and 20–40 cm in southern Guangxi, China. According to the wet-sieving approach, soil aggregates were classified as macro- (>0.25 mm) and micro- (<0.25 mm) aggregates, and the former were further divided into coarse (>2 mm), medium (2–1 mm), and fine (1–0.25 mm) fractions. Based on the mean weight diameter (MWD), the stability of soil aggregates was the highest in the 17-year-old tea plantations, and it was closely related to the concentration of soil Cact (0–20 cm: R2 = 0.9744, p < 0.05; 20–40 cm: R2 = 0.8951, p < 0.05), but not Corg (0–20 cm: R2 = 0.1532, p > 0.05; 20–40 cm: R2 = 0.4538, p > 0.05), during the tea-planting process. In the 0–20 and 20–40 cm soil layers, the coarse and medium macro-aggregates had higher concentrations of Corg, Cact, and Crec, regardless of the tea-planting age; meanwhile, the soil Cact/Crec ratio, indicating the Corg availability, increased as aggregate size increased, implying that the soil Corg was younger and more labile in coarse macro-aggregates relative to finer aggregates. Moreover, the tea-planting age significantly affected the Corg, Cact, and Crec reserves in both soil layers. To be specific, continuous tea planting facilitated the accumulation of soil Corg and Crec, but their reserves’ increase rates decreased over time; meanwhile, the soil Cact reserve increased during the early (from 8 to 17 years) tea-planting stage and later decreased. Therefore, during the middle (from 17 to 25 years) and late (from 25 to 43 years) tea-planting stages, maintaining the soil as an Cact pool plays a vital role in facilitating the formation and stabilization of soil aggregates in southern Guangxi, China.
Highlights
Tea (Camellia sinensis L.) [1], which is one of the crucial industrial crops among numerous developing countries, has been extensively grown in China, India, and Sri Lanka.China is the greatest tea producer worldwide, in which the tea plantation area takes up3.17 million hectares as of 2020 and has been continuously increasing [1]
In the 0–20 cm soil layer, the coarse macro-aggregates were dominant in soil aggregate composition, which accounted for an average proportion of 42.70% across the four tea plantations differing in age (Table 2)
In the 20–40 cm soil layer, the primary fractions in soil aggregates were micro-aggregates, which accounted for an average proportion of 52.79%
Summary
Tea (Camellia sinensis L.) [1], which is one of the crucial industrial crops among numerous developing countries, has been extensively grown in China, India, and Sri Lanka.China is the greatest tea producer worldwide, in which the tea plantation area takes up3.17 million hectares as of 2020 and has been continuously increasing [1]. China is the greatest tea producer worldwide, in which the tea plantation area takes up. Guangxi, located in the subtropical zone, is a region with plenty of light, heat, and water resources, and it provides all the favorable conditions for the development of tea plantations. As a result, it is one of the important tea-producing areas in China [2]. The global concern surrounding climate change has increased interest in promoting C sequestration in soils to mitigate the increasing CO2 level in the atmosphere [3]. Because most forest soils have experienced some degree of
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
