Phosphorus leaching at cold temperatures as affected by wastewater application and soil phosphorus levels.
Land application of wastewater in the northern-tier United States during winter months has been suggested as a means to reduce cost of building storage lagoons. A study was initiated in 1996 to assess land application of potato-processing wastewater on a 120-ha field at Park Rapids, MN. One objective of this study was to evaluate the effects of soil P levels and temperature on P leaching in soil columns. In this paper, we report the P sorption, desorption, and leaching characteristics of a high-P (>200 mg kg(-1)) and a low-P (<25 mg kg(-1)) surface soil from the wastewater irrigation site. The leaching experiment was done with wastewater at 4 +/- 2 or 10 +/- 2 degrees C. The high-P soil resulted in an equilibrium P concentration of 8.0 mg L(-1) compared with 0.14 mg L(-1) for the low-P soil. When low-P wastewater was applied to the high-P soil, the soil acted as a P source, and the total phosphorus (TP) concentration in the leachate was 3.5 times higher than the input TP concentration (C0). When high-P wastewater was applied to the high-P soil, the soil acted as a P sink retarding the TP concentration in the leachate by 80%. Phosphorus desorption was higher at 10 degrees C compared with 4 degrees C. The results showed that depending on P levels of the soil and the wastewater, reduction or increase in leachate P will occur below the surface soil. However, further mobility of this P under field conditions will depend on the volume and rate of percolating water as well as the sorption-desorption characteristics of the subsoil.
Mamo
M
M
Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE 68583, USA. mmamo3@unl.edu
Gupta
S C
SC
Rosen
C J
CJ
Singh
U B
UB
D000327:Adsorption; D010758:Phosphorus / Q000032:analysis* / Q000737:chemistry*; D012621:Seasons; D012987:Soil; D012995:Solubility; D014481:United States; D014865:Waste Disposal, Fluid / Q000379:methods*
D012987:Soil; D010758:Phosphorus