Decreased inorganic N supply capacity and turnover in calcareous soil under degraded rubber plantation in the tropical karst region
| Autor: | Hui Yang, Christoph Müller, Kang Ni, Zhongcheng Jiang, Zhijie Shan, Jun Shan, Farzaneh Garousi, Tongbin Zhu, Jianhua Cao, Jin-Ling Yang |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
inorganic chemicals
biology Phosphorus food and beverages Soil Science chemistry.chemical_element 04 agricultural and veterinary sciences Mineralization (soil science) 010501 environmental sciences biology.organism_classification complex mixtures 01 natural sciences Soil quality chemistry.chemical_compound Agronomy Nitrate chemistry Soil retrogression and degradation Soil water 040103 agronomy & agriculture 0401 agriculture forestry and fisheries Environmental science Hevea brasiliensis Calcareous 0105 earth and related environmental sciences |
| Zdroj: | Geoderma. 381:114754 |
| ISSN: | 0016-7061 |
| DOI: | 10.1016/j.geoderma.2020.114754 |
| Popis: | Investigating soil inorganic nitrogen (N) supply and availability can guide soil improvement of rubber (Hevea brasiliensis) plantations in tropical regions, but the mechanisms controlling the inorganic N supply remain unknown. In this study, three natural forests and three degraded rubber plantations located in a tropical karst region of southwestern China were sampled to determine the gross N transformation rates using a 15N tracing method. The soils of the natural forests were characterized by a high inorganic N supply capacity and a high-level nitrate (NO3−) production potential, due to the high rates of organic N mineralization to ammonium (NH4+) (MNorg) and NH4+ oxidation to NO3− (ONH4) but relatively low rates of immobilization of NH4+ (INH4) and NO3− (INO3) to organic N and dissimilatory NO3− reduction to NH4+ (DNRA). In the soils of the degraded rubber plantations, the rates of MNorg, ONH4, INO3, and DNRA were lower but the rates of NH4+ adsorption on cation-exchange sites (ANH4) increased, resulting in reductions in the inorganic N supply capacity and N availability. In addition, NO3− turnover in the soils of the degraded rubber plantations decreased, accompanied by a high mean residence time of NO3− and low δ15N values. Soil total N, organic C, phosphorus, and potassium concentrations, water-holding capacity, cation-exchange capacity, and sand content were significantly lower in the soils of the degraded rubber plantations than in those of the natural forests, indicating a decline in soil quality in the former. The significant, positive relationships between these soil properties and the rates of MNorg, ONH4, INO3, and DNRA highlight the importance of the appropriate application of organic N fertilizers as well as phosphorus and potassium fertilizers to stimulate soil N cycling and thereby increase the inorganic N supply. A reduction of the N deficiency in soils used for rubber tree cultivation would alleviate the soil degradation that characterizes many rubber plantations in tropical karst regions. |
| Databáze: | OpenAIRE |
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