The effect of irrigation and urine application on phosphorus losses to subsurface flow from a stony soil

Factors such as irrigation and soil pH can increase the solubility of P and its loss to water. Urine patches are known to alter pH but it is unknown if this increases P loss. This study investigated subsurface P loss from a stony soil under irrigation with or without the application of urine. Results showed that despite receiving urine average concentrations were significantly (P < 0.05) lower than non-urine treatments. Increasing the rate (not amount) of irrigation did not affect the load of P lost, thought to be due to attenuation. Lower P losses following urine application were due to the buffering effect of the soil and enhanced P uptake as dry matter production increased in response to N in urine. However, concentrations still exceeded guidelines. Strategies should be considered to decrease losses.