Abstract
Soil organic carbon (SOC) plays a critical role in carbon cycling and soil quality of agroecosystems. Understanding the factors influencing SOC and the main indicators for soil quality can help in better soil management and sustainable agriculture. In this study, we selected three upland fields (U1, U2 and U3) and three paddy fields (P1, P2 and P3) of saline-alkali agroecosystems to study the impacts of soil physico-chemical properties (soil pH, exchangeable sodium percentage, electrical conductivity and bulk density) and enzyme activities (soil amylase, invertase, catalase and polyphenol oxidase) on SOC dynamics. The soil pH and exchangeable sodium percentage (ESP) had profoundly negative effect on SOC. Soil amylase and invertase activities were significantly positively correlated with SOC in both upland and paddy fields. Catalase promoted the accumulation of paddy SOC and polyphenol oxidase led to the acceleration of decomposition of upland SOC. Additionally, we combined SOC contents, soil physico-chemical properties and soil enzyme activities together to obtain the main indicators of soil quality. The results suggested that, in upland sites, the main factors affecting the soil quality were soil pH, ESP and SOC. As for paddy sites, the main indicators of soil quality were soil pH, amylase and invertase. By comparing the soil quality indicators between upland and paddy fields, it was observed that the inhibiting effect of ESP on paddy soil quality was not as significant as on upland soil quality due to the irrigation practice of rice planting, which could reduce the degree of soil alkalization. Therefore, paddy development has been widely used to improve the saline-alkali land in western Jilin Province of China.
Highlights
Soils, acting as an important component in terrestrial ecosystem, contain the largest organic carbon sink [1,2]
The soil organic carbon (SOC) content of topsoil was significantly higher than the content of subsoil no matter at which sampling sites and crop growing periods (Table 2), the SOC content of upland sites and paddy sites averagely decreased 21.82% and 34.40% with the depth of soil layers, respectively
Our study was conducted to understand the impacts of soil physico-chemical properties and enzyme activities on SOC content of three saline-alkali upland fields (U1, U2 and U3) and three saline-alkali paddy fields (P1, P2 and P3) in western Jilin Province
Summary
Soils, acting as an important component in terrestrial ecosystem, contain the largest organic carbon sink [1,2]. SOC is a key attribute in maintaining soil tilth and quality and energy source for microorganisms in soils. It influences other soil functions, such as the charge characteristics, aggregate stability, water holding capacity, and so on [7,8]. Catalase and polyphenol oxidase belong to soil oxidoreductases and they are the kind of enzymes that can carry out redox reaction in soil, participating in the cycling of carbon [20]. Previous works reported that SOC had significant positive relation with the activities of soil amylase, invertase [21] and catalase [22]. It was found that polyphenol oxidase was an enzyme capable of degrading protein polyphenol complexes, having a strong effect on carbon mineralization [23,24]
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.
