Determining Phosphorus and Sediment Release Rates from Five Irish Tillage Soils

Abstract

The aim of this study was to compare the nutrient and sediment releases from five Irish tillage soils, inclined at 10- and 15-degree slopes, under a simulated rainfall intensity of 30 mm h(-1) in a controlled laboratory study. Using the relationship between soil test phosphorus (STP) in the five soils and the dissolved reactive phosphorus (DRP) released in surface runoff, a runoff dissolved phosphorus risk indicator (RDPRI) was developed to identify the STP level for Irish tillage soils above which there may be a potential threat to surface water quality. The results of this study indicated that tillage soils may produce surface runoff P concentrations in excess of 30 microg L(-1) (the value above which eutrophication of rivers is likely to occur and the maximum allowable concentration of DRP in rivers under the EU Water Framework Directive, WFD) if their Morgan's phosphorus (P(m)), Mehlich 3 phosphorus (M3-P), and water extractable phosphorus (WEP) concentrations exceed 9.5 mg L(-1), 67.2 mg kg(-1), and 4.4 mg kg(-1), respectively. This work reinforces the statutory agronomic based requirements of the European Communities (Good Agricultural Practice for Protection of Waters) Regulations 2009 (S.I. no. 101 of 2009). A statistical analysis showed that WEP gave the best prediction for runoff DRP.

Differences in available phosphorus evaluated by soil tests in relation to detection by colorimetric and ICP-AES techniques

“…From the environmental point of view, in aquatic systems, phosphorus is determined on the colorimetric reaction of phosphate with an acidified molybdate reagent to yield phosphomolybdate heteropolyacid, which is then reduced to an intensely coloured blue compound and is specified as 'dissolved reactive phosphorus' (Robards et al 1994, Worsfold et al 2005, Soldat et al 2009, Regan et al 2010 or as 'dissolved molybdate-reactive phosphorus' (Styles and Coxon 2006). It is supposed that the molybdate-reactive phosphorus should be mainly equal to the inorganic orthophosphate.…”

Impact of biochar addition to soil on greenhouse gas emissions following pig manure application

“…The soil used in this study was an Acid Brown Earth (Regan et al, 2010) collected to a 133 depth of 0.2 m from a tillage farm near Fermoy, County Cork. The 0.2m depth was chosen as 134 this is an average plough depth for tillage soil.…”

A review of phosphorus and sediment release from Irish tillage soils, the methods used to quantify losses and the current state of mitigation practice

“…Using the relationship between STP in fi ve Irish tillage soils and the DRP released in the surface runoff, Regan et al (2010) developed a runoff dissolved phosphorus risk indicator to identify the STP level above which there may be a potential threat to surface water quality. The results of this study complemented the agronomic guidelines of the Nitrates Directive.…”