ABSTRACT
A laboratory incubation study was conducted for 35 days to determine the water-soluble phosphorus (WSP) recovery from manure treated soils as influenced by four amendments, spent lime, gypsum, leonardite, and alum. For soil with pH 8.1, WSP of control (soil+manure) increased from 40.1 to 61.8 mg kg−1 on 35 d, application of alum, leonardite, spent line, and gypsum reduced the WSP to 0.15 mg kg−1 (99%), 13.3 mg kg−1 (78%), 34.1 mg kg−1 (45%), and 39.8 mg kg−1 (36%), respectively. Soil with pH 6.7, control had initial WSP of 40.9 mg kg−1 and increased to 80.3 mg kg−1 on 35 d, spent lime, alum, gypsum, and leonardite reduced WSP to 23.6 mg kg−1 (71%), 27.4 mg kg−1 (66), 33.5 mg kg−1 (58%), and 61.1 mg kg−1 (24%), respectively. Alum worked for both soils but the performance of other amendments depends on soil pH and concentration of exchangeable calcium and aluminum.
Acknowledgement
Authors are thankful to Dr. Larry J. Cihacek, Department of Soil Science, North Dakota State University for providing the Nebraska soil sample.