Abimbola Ojekanmi, University of Manitoba, Soil Science Department, 362 Ellis, Building., Winnipeg, MB R3T 2N2, CANADA, Olalekan Akinremi, 362 Ellis Building, University of Manitoba, University of Manitoba, Dept. of Soil Science, Winnipeg, MB R3T 2N2, CANADA, and Xiying Hao, CANADA Lethbridge Res. Station, AAFC Lethbridge Research Cntr., 5403 1st Ave. S, Lethbridge, AB T1J 4B1, CANADA.
The impact of long term manure application at and above recommended rates is of environmental importance, as it affects the physical, chemical and biological properties of soil and water. In order to examine the sustainability of such practice in regions with intensive livestock production, fall manure application was initiated on a dark brown clay loam chenozerm with calcareous profile in 1973 with either irrigated (0, 60, 120, Mgha-1ha-1) or rainfed (0 Mgha-1ha-1) plots. After 33 years of continuos manure application, the soil P content and distribution were examined by analyzing for Total P (Parkinson et al 1952) and the sequentially extracted form of P in water, NaHCO3, NaOH, HCl, and Residual P (Kashem et al 2004). Soil total P analysis indicate increasing surface accumulation of P during the 33 years with significant impact of such manure application up to a depth of 60 cm. P content at 0-30cm and 30-60cm increases with increasing rate of manure application while P content at 60-150cm depth remained constant. The effect of continuous application of manure on the forms of P in the 0-30cm and 30-60cm depths will be presented and discussed