Plant-Available and Water-Soluble Phosphorus in Soils Amended with Separated Manure Solids
- M.-O. Gassera,
- M. H. Chantigny *b,
- D. A. Angersb,
- S. Bittmanc,
- K. E. Buckleyc,
- P. Rochetteb and
- D. Masséd
- a Institut de recherche et de développement en agroenvironnement (IRDA), Québec, QC G1P 3W8 Canada
b Agriculture and Agri-Food Canada, Québec, QC G1V 2J3 Canada
c Agriculture and Agri-Food Canada, Agassiz, BC V0M 1A0 Canada.
c Agriculture and Agri-Food Canada, Brandon MB R7A 5Y3 Canada
d Agriculture and Agri-Food Canada, Sherbrooke, QC, J1M 1Z3 Canada. Assigned to Associate Editor Gurpal Toor
Physical, chemical, or biological treatment of animal liquid manure generally produces a dry-matter rich fraction (DMF) that contains most of the initial phosphorus (P). Our objective was to assess the solubility and plant availability of P from various DMFs as a function of soil P status. Eight different DMFs were obtained from liquid swine (LSM) and dairy cattle (LDC) manures treated by natural decantation, anaerobic digestion, chemical flocculation, composting, or mechanical separation. The DMFs were compared with mineral P fertilizer in a pot experiment with oat (Avena sativa L.) grown in four soils with varied P-fixing capacities and P saturation levels. The DMFs were added at a rate of 50 mg P kg−1 soil and incubated 14 d before seeding. Soil water–extractable P (PWT) at all water:soil extraction ratios (2:1, 20:1, and 200:1) was slightly higher when DMFs were derived from LDC rather than LSM. Soil PWT at the 2:1 ratio was lower with anaerobically digested LSM. At the 2:1 extraction ratio, DMF P was less soluble than mineral P as P saturation in soils increased. In soils with a lower P-fixing capacity, DMF P appeared less water soluble than mineral P under 20:1 and 200:1 extraction ratios. After 72 d of plant growth, DMFs produced yields comparable to mineral P fertilizer. Although the plant availability of P from DMFs was comparable to mineral P fertilizer, P from DMFs could be less vulnerable to leaching or runoff losses in soils with a high P saturation level or low P-fixing capacity.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2012. . Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.