|Author:||Barlow, K. ; Nash, D. ; Grayson, R. B.|
|Book Group Author:||NA|
Phosphorus (P) exported from agricultural land contributes to the eutrophication of inland water systems. Although P export has been extensively researched at the paddock scale, our understanding of farm-scale export is limited. This paper presents the results of a 3-year monitoring project that investigated P export at the paddock, farm-section, and whole farm scales on an irrigated dairy farm in south-eastern Australia. Annual average concentrations of 2.2-11 mg P/L, and annual loads of 2.5-23 kg P/ha were measured at the paddock and farm-section scale over the 3 years, with the quality of irrigation water applied having no significant effect on P export in surface runoff. At the farm scale, effective management of the water reuse system significantly reduced phosphorus export by up to 98%. During the 3-year period, P concentrations and loads exported in surface runoff consistently decreased between the paddock and farm-section scales (e.g. P-28 exported 13.8 kg P/ha, whereas S-4 exported 6.7 kg/ha in 2001), with the decrease in P export described using a scaling factor. Our results suggest that data on paddock-scale P export can rarely be proportionally assigned to predict section- or farm-scale export, at least on irrigated dairy farms in south-eastern Australia.
|Pages:||1 - 9|
|Journal:||Australian Journal of Agricultural Research|
agricultural land, agricultural soils, dairy farms, erosion,irrigated conditions, irrigated farming, overland flow, paddocks,phosphorus, runoff, soil types, water management, water reuse, watersystems, Australia, Victoria, Australasia, Oceania, Developed Countries,Commonwealth of Nations, OECD Countries, Australia, farmland, waterresource management, Soil Physics (JJ300), Soil Water Management(Irrigation and Drainage) (JJ800) (Revised June 2002) [formerly SoilWater Management], Animal Husbandry and Production (LL180) (New March2000), Water Resources (PP200), Erosion; Soil and Water Conservation(PP400)