Pig effluent-P application can increase the risk of P transport: two case studies

Abstract

Land application of piggery effluent (containing urine, faeces, water, and wasted feed) is under close scrutiny as a potential source of water resource contamination with phosphorus (P). This paper investigates 2 case studies of the impact of long-term piggery effluent-P application to soil.A Natrustalf (Sodosol) at P1 has received a net load of 3700 kg effluent P/ha over 19 years. The Haplustalf (Dermosol) selected (P2) has received a net load of 310 000 kg P/ha over 30 years. Total, bicarbonate-extractable, and soluble P forms were determined throughout the soil profiles for paired (irrigated and unirrigated) sites at P1 and P2, as well as P sorption and desorption characteristics.Surface bicarbonate (P B , 0-0.05 m depth) and dilute CaCl 2 -extractable molybdate-reactive P (P C ) have been significantly elevated by effluent irrigation (P1: P B unirrigated 23±1, irrigated 290±6; P C unirrigated 0.03±0.00, irrigated 23.9±0.2; P2: P B unirrigated 72±48, irrigated 3950±1960; P C unirrigated 0.7±0.0, irrigated 443±287 mg P/kg; mean±s.d.). Phosphorus enrichment to 1.5 m, detected as P B , was observed at P2. Elevated concentrations of CaCl 2 -extractable organic P forms (P OC ; estimated by non-molybdate reactive P in centrifuged supernatants) were observed from the soil surface of P1 to a depth of 0.4 m. Despite the extent of effluent application at both of these sites, only P1 displayed evidence of significant accumulation of P OC .The increase in surface soil total P (0-0.05 m depth) due to effluent irrigation was much greater than laboratory P sorption (>25 times for P1; >57 times for P2) for a comparable range of final solution concentrations (desorption extracts range 1-5 mg P/L for P1 and 50-80 mg P/L for P2). Precipitation of sparingly soluble P phases was evidenced in the soils of the P2 effluent application area.

Role of organic amendments on enhanced bioremediation of heavy metal(loid) contaminated soils

“…Sajwan and Youngblood [167] reported increased growth of Sorgum with mixtures of fly-ash and biosolid in a greenhouse study. In addition, additional materials may be necessary to increase fertility or reduce leaching and runoff losses of environment contaminants, such as P and N [168][169][170][171]. It is often the case that a single waste material does not possess all the properties required to ameliorate site contamination, acidity, sodicity, etc.…”

Retention, Accumulation, and Movement of Phosphorus in a Mollisol Soil Irrigated With Dairy Effluent in a Tropical Environment

“…Continuous application of animal effluent especially at high rates over a number of years is expected to eventually exhaust the P sorption sites and lead to increases in extractable P in the future. This has already been reported for areas where animal wastes have been continuously applied (Sanderson et al, 2001;Johnson et al, 2004;Redding, 2001).…”

“…A study in Texas involving dairy effluent fertilization of BAlamo[ Switchgrass (Panicum virgatum L.) planted as filter strip, indicated that soil P increased with increasing rates of effluent application (Sanderson et al, 2001). Phosphorus accumulated in systems that received both short-term (Johnson et al, 2004) and long-term (Redding, 2001) animal effluent application.…”

“…Phosphorus has been generally considered immobile, being readily sorbed by the soil, yet, its downward movement has been reported in undisturbed soil core experiments (Phillips, 2002), grasslands used for effluent application (Toor et al, 2004;Barton et al, 2005), horticultural crop land fertilized with pig effluent (Redding, 2001), and in areas of high animal manure application or extensive animal feeding operations (Hansen et al, 2002;Mozaffari and Sims, 1994). Holford et al (1997) examined the effects of dairy, pig, and sewage effluent and other materials containing P on the P sorption characteristics of two Australian soil groups.…”

Treatment of Wastewater With Slow Rate Systems: A Review of Treatment Processes and Plant Functions

“…Leaching of phosphorus at depths of 0.6 and 1.5 m was reported in two sites irrigated with piggery wastewater for 19 and 30 years, respectively (Redding, 2001). Likewise, increased concentrations of phosphorus were observed in drainage water at a depth of 0.65 m in a soil having received livestock wastes for a period of 150 years (Heckrath et al, 1995).…”