RT Journal Article
SR Electronic
T1 Long-term trends in phosphorus leaching and changes in soil phosphorus with phytomining
JF Journal of Soil and Water Conservation
FD Soil and Water Conservation Society
SP 121
OP 132
DO 10.2489/jswc.70.2.121
VO 70
IS 2
A1 A. Svanbäck
A1 B. Ulén
A1 L. Bergström
A1 P.J.A. Kleinman
YR 2015
UL http://www.jswconline.org/content/70/2/121.abstract
AB Few mitigation strategies exist to reduce phosphorus (P) losses in leachate once soil P has built up. “Phytomining,” or harvesting a crop without application of fertilizer P to create a negative P balance, has been proposed as a strategy for lowering soil P levels and preventing P loss to runoff and leachate. In this study crops were grown and harvested over 7 to 16 years in undisturbed soil columns (105 cm [41 in] deep) with contrasting textures (loamy sand, sandy loam, silty clay loam, and clay) and high P levels, while P loss in leachate was measured. Soil test P in the topsoil (0 to 20 cm [0 to 8 in] depth) was significantly decreased from the beginning to the end of the study for all soils, while a significant decreasing trend in dissolved reactive P in leachate was only observed in one soil. Downward movement of P from the topsoil to deeper layers was indicated to occur in three out of four soils. Although phytomining lowered soil test P by 11% to 37% in topsoils over the 7 to 16 year period of the study, results indicate that soils with P content well above agronomic optimum may take a much longer time to reach the agronomic optimum.