Abstract
Concentrations were measured of various forms of soil P in the Ap horizon of a Lethbridge loam (Dark Brown Chernozemic) brought about by 20 yr of feedlot manure loading or 14 yr of feedlot manure loading + 6 yr of no further additions under both nonirrigated and irrigated conditions. Depth of cultivation affected the concentrations of the various P fractions. Although total P and phosphatase activity increased with manure additions, these increases diminished at triple the recommended loading rates. Increased phosphatase activities never rose above those of the soil from ungrazed native prairie. Irrigation increased the phosphatase activity of the control treatment. Concentrations of total P remained well above those of the control plots, even after 6 yr without any additional manure loading. New approaches to the estimation of P fractions are needed to understand P in land used for manure disposal. Key words: Phosphatase activity, labile phosphorus, pollution, phosphorus harvesting, cultivation depth
Publisher
Canadian Science Publishing
Cited by
29 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献