Phosphorus Accumulation and Sorption in Calcareous Soil under Long-Term Fertilization |
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| Authors: | Rui Wang Shengli Guo Nana Li Rujian Li Yanjun Zhang Jishao Jiang Zhiqi Wang Qingfang Liu Defeng Wu Qiqi Sun Lanlan Du Man Zhao |
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| Institution: | 1. College of Resources and Environment, Northwest A&F University, Yangling 712100, Shaanxi, China.; 2. Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China.; 3. Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resource, Yangling 712100, Shaanxi, China.; Huazhong University of Science and Technology, CHINA, |
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| Abstract: | Application of phosphorus (P) fertilizers to P-deficient soils can also result in P accumulation. In this study, soil P status and P uptake by apple trees were investigated in 5-, 10-, and 15-year-old orchards in the semi-arid Loess Plateau, China, and subset soils with different soil P statuses (14–90 Olsen-P mg kg−1) were selected to evaluate the characteristic P adsorption. Due to the low P-use efficiency (4–6%), total soil P increased from 540 mg kg−1 to 904 mg kg−1, Olsen-P ranged from 3.4 mg kg−1 to 30.7 mg kg−1, and CaCl2-P increased from less than 0.1 mg kg−1 to 0.66 mg kg−1 under continuous P fertilization. The P sorption isotherms for each apple orchard were found to fit the Langmuir isotherm model (R
2 = 0.91–0.98). K (binding energy) and Q
m (P sorption maximum) decreased, whereas DPS (degree of phosphorus sorption) increased with increasing P concentration. CaCl2-P increased significantly with the increase of Olsen-P, especially above the change point of 46.1 mg kg−1. Application of surplus P could result in P enrichment in P-deficient soil which has high P fixation capacity, thus posing a significant environmental risk. |
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