The effect of long-term application of P fertilizer on soil grown forage plants
Peer Reviewed StatusNon-Peer Reviewed
MetadataShow full item record
Phosphorus (P) fertilization does not always increase crop yields but the repeated use of P may modify the biological properties of soils. The objective of the present study, therefore, was to investigate the effect of long term applications of P fertilizer on soil biological properties. We used an experimental site located in Swift Current in which different amounts of P (0, 20 and 40 kg P2O5 ha-1) were applied annually for the past 8 years on alfalfa and alfalfa-Russian wild rye hay crops. Our hypothesis was that repeated application of P influences soil microbial biomass and various soil enzymes. Microbial biomass C in the 0-7.5 cm soil layer was determined by fumigation-extraction at each of three harvest dates, and dehydrogenase, acid phosphatase and urease activities were assayed. Application of P to soil increased soil available P, dissolved organic C and available NO3-N, but did not significantly affect crop yields or soil microbial biomass C. Arbuscular mycorrhizal colonization of crop roots, and dehydrogenase and urease activities were decreased, suggesting that P reduced soil microbial activity. Acid phosphatase activity remained unchanged with P fertilization, suggesting that P availability was not limiting in these systems. While 8 years of application of P had little effect on hay yields, it generally reduced the activity of the soil microbial biomass.
Part OfSoils and Crops Workshop
soil biological activity
The following license files are associated with this item: