Reducing Phosphorus Runoff and Leaching from Poultry Litter with Alum: Twenty‐Year Small Plot and Paired‐Watershed Studies

Abstract

Treating poultry litter with alum has been shown to lower ammonia (NH) emissions and phosphorus (P) runoff losses. Two long-term studies were conducted to assess the effects of alum-treated poultry litter on P availability, leaching, and runoff under pasture conditions. From 1995 to 2015, litter was applied annually in a paired watershed study comparing alum-treated and untreated litter and in a small plot study comparing 13 treatments (an unfertilized control, four rates of alum-treated litter, four rates of untreated litter, and four rates of NHNO). In the paired watershed study, total P loads in runoff were 231% higher from pasture receiving untreated litter (1.96 kg P ha) than from that receiving alum-treated litter (0.85 kg P ha). In both studies, alum-treated litter resulted in significantly higher Mehlich III P (M3-P) and lower water-extractable P at the soil surface, reflecting greater retention of applied P and lesser availability of that P to runoff or leaching. In soils fertilized with alum-treated litter, M3-P was much higher when analyzed by inductively coupled argon plasma emission spectrometry than by colorimetry, possibly due to the formation of aluminum phytate. Indeed, alum-treated poultry litter leached less P over the 20-yr study: M3-P at 10 to 50 cm was 266% greater in plots fertilized with untreated litter (331 kg M3-P ha) than with alum-treated litter (124 kg M3-P ha). This research provides compelling evidence that treating poultry litter with alum provides short-term and long-term benefits to P conservation and water quality.

The Contrasting Effects of Alum‐Treated Chicken Manures and KH2PO4 on Phosphorus Behavior in Soils

“…In China, overapplication of manure has produced undesirable impacts on water quality (Wu and Chen 2013; Chadwick et al, 2015). Alum has been proven to be highly effective for immobilizing P in chicken manure or litter (Moore et al, 2000; Huang et al, 2016). This was confirmed in the current study, particularly for WSRP (Fig.…”

“…It is now well understood that long‐term application of animal manure will increase both the reactive (RP) and nonreactive P (NRP) pools in soils receiving the manure (Pagliari and Laboski 2013, 2014; Waldrip et al, 2015). For example, Eghball et al (1996) found that available P increased to a soil depth of 1.8 m after 40 yr of manure application, whereas Huang et al (2016) observed a significant increase in Mehlich‐3 P in the soil profile after 20 yr of poultry litter application. Phosphorus accumulation in soils increases the potential risk for P loss, which has been defined as a major environmental threat to receiving aquatic ecosystems (Schroeder et al, 2004; Wu and Chen, 2013).…”

“…One tentative effort is to use chemical additives to reduce P solubility (Moore, 2016). Among the chemical additives, alum [KAl(SO 4 ) 2 ⋅12H 2 O] is the most effective (Moore et al, 2000; Smith et al, 2004; Huang et al, 2016). A 20‐yr study showed that application of alum‐treated chicken litter reduced water‐soluble P in soils compared with untreated litter, without sacrificing forage yields (Moore and Edwards, 2007; Huang et al, 2016).…”

“…Among the chemical additives, alum [KAl(SO 4 ) 2 ⋅12H 2 O] is the most effective (Moore et al, 2000; Smith et al, 2004; Huang et al, 2016). A 20‐yr study showed that application of alum‐treated chicken litter reduced water‐soluble P in soils compared with untreated litter, without sacrificing forage yields (Moore and Edwards, 2007; Huang et al, 2016). Alum addition also decreased N loss by ammonia volatilization (Moore et al, 2000), enhanced heavy metal immobilization (Moore et al, 1998), and suppressed the spread of pathogenic bacteria (Rothrock et al, 2008).…”

Managing Surface Water Inputs to Reduce Phosphorus Loss from Cranberry Farms

“…Low dissolved concentrations of Al and Fe in the study ponds were consistent with levels found in regional ponds (Table 1; Mattson et al, 1992), likely increasing P removal efficiency of Al and Fe based treatments (Leytem and Bjorneberg, 2005). Given the relatively low Ca and P concentrations, as well as the slightly acidic pond water pH (Table 1), precipitation of Ca‐P could be suppressed in pond water used for cranberry production (Jenkins et al, 1971; Diaz et al, 1994; Song et al, 2002). …”