1. Soil phosphorus storage capacity as affected by repeated phosphorus addition in an Ultisol.
- Author
-
Xu, Xinghong, Wang, Yanling, Zhang, Hailin, Yin, Dan, Dari, Biswanath, and Xu, Jiangbing
- Subjects
PHOSPHORUS in soils ,RED soils ,SOIL management ,SOIL testing ,PHOSPHORUS - Abstract
Soil phosphorus (P) loss risk and environmental impact can be assessed by different soil test indicators such as soil P storage capacity (SPSC), a site-specific and reliable measurement of soil P status. In this study, the changing trends of soil P saturation ratio (PSR) and SPSC in red soil (equivalent to Ultisol) were discussed after 10 consecutive additions of P solution with 20 mg P L
−1 , and the relationships between Olsen-P, CaCl2 -P, and PSR, SPSC also were evaluated. Results showed that the soil PSR was increased to 0.22 at the end of P addition, and the accumulated P was high to 1625 mg kg−1 . The threshold PSR of the red soil was determined to be 0.10, and the SPSC significantly decreased from 242.0 mg kg−1 to −382.1 mg kg−1 with the increase of P addition times. When SPSC = 0, the accumulated P in red soil was 487.7 mg kg−1 . Therefore, there existed four stages for the soil P management in red soil according to the changes of SPSC and Olsen-P: short supply stage of soil P (SPSC>88 mg kg−1 and Olsen-P ≤ 20 mg kg−1 ), stable supply stage of soil P (68 mg kg−1 < SPSC≤88 mg kg−1 and 20 mg kg−1 < Olsen-P ≤ 40 mg kg−1 ); over supply stage of soil P (0< SPSC≤68 mg kg−1 and 40 mg kg−1 < Olsen-P ≤ 108 mg kg−1 ), and the high loss risk stage of soil P (SPSC≤0 and Olsen-P > 108 mg kg−1 ). In the last stage, P fertilization must be stopped and environmental protection measures must be taken immediately. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF