Sensitivity of soil phosphorus tests in predicting the potential risk of phosphorus loss from pasture soil

Abstract

The objective of this study was to examine the effects of urine and dung additions on the phosphorus (P) chemistry of pasture land and to compare the sensitivity of two soil extraction methods in assessing the P-loading risk. In a field experiment, urine and dung were added to soil in amounts corresponding to single excrement portions and the soil samples, taken at certain intervals, were analysed for pH H2O , acid ammonium acetate extractable P (P Ac ) and water extractable total P (TP w ), and molybdate reactive P (MRP w ). Urine additions immediately increased soil pH and MRP w , but no such response was observed in P Ac extraction due to the low pH (4.65) of the extractant enhancing the resorption of P. The P Ac responded to the dunginduced increase in soil total P similarly as did P w , which suggests that both tests can serve to detect areas of high P concentration. However, water extraction was a more sensitive method for estimating short-term changes in P solubility. In pasture soils, the risk of P loss increases as a result of the interaction of urination and high P concentration in the topsoil resulting from continuous dung excretion.

Management options to decrease phosphorus and sediment losses from irrigated cropland grazed by cattle and sheep

“…Although P concentrations in dung can be similar, the amount of dung excreted by cattle per day is far greater than by sheep (∼25 kg/day per head for cattle and 1.4 kg/day per head for sheep) (Haynes & Williams, 1993). It is also possible that N deposition in urine may have altered soil P concentrations because sheep tend to urinate more than cattle (Soinne et al. , 2008).…”

Vegetation, nutrients, and CO₂ flux dynamics in northern boreal forests

“…Several studies have shown the importance of the relationship of soil N and boreal vegetation cover. So far, soil P in boreal forests has received relatively little interest compared to N, and most studies regarding P have concentrated on former agricultural lands (Peltovuori 2007;Soinne et al 2008) or on peatlands (e.g. Moilanen et al 2010).…”