PHOSPHORUS RETENTION BY THE Ap HORIZON OF A SPODOSOL AS INFLUENCED BY CALCIUM AMENDMENTS 1

Abstract

The low capacity of acid sandy soils to bind P is one reason for the leaching and runoff of P from these soils. Various soil amendments have been used to reduce P leaching. This study was conducted to show the effect of CaCO 3 , dolomite, gypsum, and CaCl 2 on P retention by the Ap horizon of a Spodosol. Phosphorus sorption was studied in a batch experiment at an initial P concentration range of 0 to 10 mg L ؊1 . The amendment rate used was 0.05 mmol of either Ca or Ca ؉ Mg (and also 0.1 mmol in the case of CaCO 3 and gypsum) per g of soil. The influence on P retention of time after soil amendment (1 h to 1 week) was assessed. P adsorption was described by Langmuir and Freundlich equations. All amendments, except for CaCl 2 , increased soil pH and P retention by soil. CaCO 3 was more effective then dolomite, the carbonates (CaCO 3 and dolomite) were more effective in their interaction with the soil, and gypsum increased P retention by itself, its effect was weakened upon interaction with soil. Sorption of P in soil amended with gypsum was faster than sorption in soil amended with CaCO 3 . The effect of the amendments under study was mainly to provide Ca ions, which must be accompanied by an increase in pH to increase P retention. (Soil Science 2003;Volume 168:699-706)

Lime and Gypsum as Source Measures to Decrease Phosphorus Loss from Soils to Water

“…To conclude, the contrast in effectiveness of lime and gypsum, and the observed increases in RP solubility in limed soils with the largest pH increases, suggest that any effectiveness of these two source measures is due largely to increases in Ca concentration, rather than pH. Boruvka and Rechcigl (2003) concluded that lime and gypsum were effective as P source measures due to increased Ca concentrations but, in contrast to this study, they concluded that an increase in pH was also required. pH in limed soils in their study reached 7.4 and 7.8.…”

“…Although it is often neglected in studies of P source measures and P loss in general (Boruvka and Rechcigl 2003;Callahan et al 2002;Stout et al 2003;Torbert et al 2005), OP can be an important fraction in soil solution and P loss (Murphy 2007;Toor et al 2003). Organic P can become bio-available and contribute to eutrophication in receiving water bodies through chemical or enzymatic hydrolisation (Correll 1998).…”

“…Anderson et al (1995) found that gypsum decreased P solubility by 40% to 68%. Boruvka and Rechcigl (2003) found that gypsum increased P retention several times relative to a control. Callahan et al (2002) found that gypsum consistently decreased water-extractable P in three acid soils and one neutral soil and Stout et al (2003) found that gypsum decreased water-extractable P by 38% to 57% in three acidic soils.…”

Effects of a livestock manure windrow composting site with a fly ash pad surface and vegetative filter strip buffers on sediment, nitrate, and phosphorus losses with runoff

“…They also found constructing a 0.73-ha (1.80-ac) windrow composting pad from lime and fly ash materials was approximately 28% of the cost of a comparable-size 15-cm (6.0-in) thick concrete pad. Another potential benefit of fly ash and lime composting pad materials is the P-sorbing properties reported by many researchers (Dou et al 2003;Boruvka and Rechcigal 2003;Lau et al 2001;Brauer et al 2005;DeLaune et al 2006;Penn and Bryant 2006). Dou et al (2003) found fly ash reduced soluble P by 60% from converting water soluble phosphorus (H 2 O-P) in dairy manure to sodium bicarbonate-extractable phosphorus (NaHCO 3 -P), a fraction less vulnerable to RO losses.…”

Influence of soil pH in vegetative filter strips for reducing soluble nutrient transport

“…[23,35] At higher pH, phosphorus forms insoluble calcium phosphate, which precipitated and reduced transport. [21,35,36] In an amendment study by Boruvka and Rechcigl, [37] pH was raised to 7.4-7.8 by CaCO 3 and resulted in higher P sorption. Boruvka and Rechcigl [37] and other researchers [38,39] concluded that the Ca ion provided must be accompanied with an increase in pH for direct precipitation and sorption.…”