Estimating soil phosphorus sorption saturation from Mehlich-3 data

Abstract

Soil phosphorus sorption saturation (P sat ) measures the degree to which soil phosphorus (P) sorption sites have been filled and has been found to be a good indicator of P availability to runoff and leachate. At present, analytical methods required to estimate P sat are generally not offered by soil testing laboratories. This study evaluated the use of Mehlich-3 data in estimating P sat in a wide range of soils. In acidic soils ðpH ¼ 4:1-5:9Þ; P sat estimated from Mehlich-3 P, iron (Fe), and aluminum (Al) was highly correlated with P sat estimated from ammonium oxalate data ðr ¼ 0:94Þ as well as with a reference P sat estimated from bicarbonate P and the Langmuir sorption maximum ðr ¼ 0:89Þ: In alkaline soils ðpH ¼ 7:3-8:4Þ; P sat estimated with Mehlich-3 P and calcium (Ca) was highly correlated with the reference P sat ðr ¼ 0:84Þ; and the strength of that correlation improved only slightly by factoring in soil clay content ðr ¼ 0:86Þ: Results indicate that P sat may be 1825 effectively estimated from Mehlich-3 data across a wide range of soils. This study confirms that P sat may be readily estimated by soil testing laboratories that routinely measure Mehlich-3 P, Al, Fe, and Ca.

Sorption of Phosphorus from Swine, Dairy, and Poultry Manures

“…Surprisingly, the slopes of the regression lines between PSI and Mehlich 3 Al were not statistically different in the five different solution treatments (P , 0.05). It is not uncommon for metal oxides to play a strong role in P sorption in noncalcareous soils (Berkheiser et al 1980;Hsu 1964; Van der Zee and Van Riemsdijk 1986), though unlike our study most of these correlations have been observed with oxalate-extractable Al instead of Mehlich 3-extractable Al (Beauchemin et al 2003;Borggaard et al 1990;Borling, Otabbong, and Barberis 2001;Burkitt et al 2006;Kleinman and Sharpley 2002;Pierzynski et al 1990;Traina et al 1986). …”

“…Because soil has a finite capacity to sorb P, there is much interest in obtaining accurate estimates of a soil's ability to bind additional P. An approach gaining popularity for estimating a soil's capacity to retain P is the calculation of a saturation index, sometimes referred to as the degree of P saturation (DPS) (Hooda et al 2000;Kleinman and Sharpley 2002). The DPS is a ratio of extractable P to P sorption capacity and thus quantifies the remaining sorption capability of the soil.…”

“…After equilibration, the concentration remaining in solution is measured and used to calculate the concentration sorbed to the soil. In most cases, sorption studies are conducted by adding known concentrations of inorganic P in a predefined medium such as calcium chloride (CaCl 2 ) or potassium chloride (KCl) (Borling, Otabbong, and Barberis 2001;D'Angelo et al 2003;Kleinman and Sharpley 2002;Nair et al 1984;Reddy et al 1980;Sharpley 1995;Siddique and Robinson 2003). A potential limitation to this approach, however, is that in many regions the application of P to agricultural fields is in the form of animal manure.…”

Phosphorus Sorption Kinetics in Reclaimed Lignite Mine Soils under Different Age Stands ofRobinia pseudoacaciaL. in Northeast Germany

“…Nevertheless, soils with the highest PSC have the highest sum of Fe ox and Al ox contents (Figure 7). Comparable correlations of PSC with Fe ox and Al ox have been reported in the literature [24,27,33,46,54,87,[89][90][91][92]. Numerous studies [22,29,46,89,93] have shown that the most important parameters that determine the P sorption are Fe ox and Al ox .…”

Nutrient Leaching When Soil Is Part of Plant Growth Media

“…Higher values are associated with better crop growth but potentially more leaching potential for P. The DPS ratio was determined as well as the alternate ratio [30][31][32], P/Ca, since it is better for soils with pH > 7.…”