Assessment of co-blending water treatment residual with dairy manure to reduce phosphorus concentrations in run-off in Northern Ireland

作者：O' Rourke S M^*; Foy R H; Watson C J; Gordon A; Doody D

来源：Soil Use and Management, 2012, 28(2): 157-166.

DOI：10.1111/j.1475-2743.2012.00397.x

• Phosphorus
• manure
• grassland
• run-off
• soil nutrients
• soil use and management
• water treatment residual

Losses of phosphorus (P) to water that follow manure applications can be high while water treatment residuals (WTR) have an appreciable capacity to sorb soluble P which is an important risk factor in determining the susceptibility of manure P to run-off losses. The objective of this study was to assess whether co-blending WTR with dairy cow manure prior to surface application would reduce P concentrations in run-off from grassland. An alum-derived WTR was collected from a water treatment works (WTW), dried and characterized for its phosphorus sorption capacity (PSC) based on oxalate-extractable Al and Fe. Multipoint P sorption isotherms were used to calculate the Langmuir P sorption maximum (Pmax) and equilibrium P concentration (EPC0). The WTR contained 170 g Alox/kg and 2.2 g Feox/kg with a nominal long-term PSC of 118 g/kg. Following a 6 day incubation of WTR, the Langmuir Pmax was 82.6 g/kg and the EPC0 of 0.13 mg P/L. Laboratory incubations of manure co-blended with WTR indicated that 144 g WTR/kg dry matter (DM) manure significantly lowered (P %26lt; 0.001) manure WSP by 71.5 +/- 16.6% after 108 h, but lower WTR mixing rates of 72 and 36 g WTR/kg had no statistical effect on manure WSP. Results from a field experiment using simulated rain on 0.5-m2 grassland plots showed no significant effect on run-off P 2 days after applying 50 m3/ha of 6% DM manure co-blended WTR at rates of 150 and 250 g WTR/kg.

• 出版日期2012-6