Spatial variability of ammonium and nitrate in soils near a poultry farm

This paper assesses the distribution of ammonium (NH4+) and nitrate (NO3−) nitrogen deposition in native bushland soil adjacent to an open ventilated poultry farm. The farm is located in Thirlmere 150 km south west of Sydney, Australia. A total of 104 geographically referenced soil cores were obtained from the study area. Soil pH, electrical conductivity (EC), NH4+- and NO3−-nitrogen concentrations were analysed for variable trends at three depths, i.e. 0–30, 30–60, and 60–90 cm. Significantly higher concentrations of the two nitrogen forms and EC were observed nearer to the farm in the surface soil samples (0–30 cm). The distribution of NH4+, NO3− and EC were all correlated in surface samples throughout the study area. There was no indication of NH4+ and NO3− leaching within soil profile sampled and it appears that weeds and native vegetation had utilised the accumulated nitrogen. The level of N deposition adjacent to the poultry farm decreased downwind due to dispersion of plume and to the buffering effects from the bushland.