Phosphorus Accumulation and Sorption in Calcareous Soil under Long-Term Fertilization.
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 (R2 = 0.91-0.98). K (binding energy) and Qm (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.
College of Resources and Environment, Northwest A&F University, Yangling 712100, Shaanxi, China.
Rui
R
Wang
College of Resources and Environment, Northwest A&F University, Yangling 712100, Shaanxi, China; Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China.
Shengli
S
Guo
Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China.
Nana
N
Li
Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China.
Rujian
R
Li
Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China.
Yanjun
Y
Zhang
Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resource, Yangling 712100, Shaanxi, China.
Jishao
J
Jiang
Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China.
Zhiqi
Z
Wang
College of Resources and Environment, Northwest A&F University, Yangling 712100, Shaanxi, China.
Qingfang
Q
Liu
College of Resources and Environment, Northwest A&F University, Yangling 712100, Shaanxi, China.
Defeng
D
Wu
Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resource, Yangling 712100, Shaanxi, China.
Qiqi
Q
Sun
Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China.
Lanlan
L
Du
College of Resources and Environment, Northwest A&F University, Yangling 712100, Shaanxi, China.
Man
M
Zhao
D002122:Calcium Chloride / Q000032:analysis* / Q000737:chemistry; D002681:China; D005308:Fertilizers / Q000009:adverse effects*; D027845:Malus / Q000378:metabolism*; D008962:Models, Theoretical; D010758:Phosphorus / Q000032:analysis* / Q000737:chemistry; D012987:Soil / Q000737:chemistry*
D005308:Fertilizers; D012987:Soil; D010758:Phosphorus; D002122:Calcium Chloride