Phosphorus loading and measurement is of concern on lands where biosolids have been applied. Traditional soil testing for plant-available P may be inadequate for the accurate assessment of P loadings in a regulatory e...Phosphorus loading and measurement is of concern on lands where biosolids have been applied. Traditional soil testing for plant-available P may be inadequate for the accurate assessment of P loadings in a regulatory environment as the reported levels may not correlate well with environmental risk. In order to accurately assess potential P runoff and leaching, as well as plant uptake, we must be able to measure organic P mineralized by the biotic community in the soil. Soils with varying rates of biosolid application were evaluated for mineralized organic P during a 112-day incubation using the difference between P measured using a rapid-flow analyzer (RFA) and an axial flow Varian ICP-OES. An increase in the P mineralized from the treated soils was observed from analysis with the Varian ICP-OES, but not with the RFA. These results confirm that even though organic P concentrations have increased due to increasing biosolid application, traditional soil testing using an RFA for detection, would not accurately portray P concentration and potential P loading from treated soils.展开更多
The soil extractant, H3A, has undergone several iterations to extract calcium (Ca), iron (Fe), aluminum (Al), potassium (K), phosphorus (P), ammonium (NH4-N) and nitrate (NO3-N) under ambient soil conditions. Few soil...The soil extractant, H3A, has undergone several iterations to extract calcium (Ca), iron (Fe), aluminum (Al), potassium (K), phosphorus (P), ammonium (NH4-N) and nitrate (NO3-N) under ambient soil conditions. Few soil extractants currently used by commercial and university soil testing laboratories can perform multi-nutrient extraction without over- or under-estimating at least one nutrient. Soil pH and plant root exudates have a strong influence on nutrient availability and H3A was developed to mimic soil conditions. Lithium citrate was previously used in the H3A formulation, but resulted in a cloudy supernatant in some samples, complicating laboratory analyses. In this study, we removed lithium citrate and compared the nutrients extracted from the modified (H3A-4) to the established (H3A-3) solutions. We found that the new extractant, H3A-4, produced a clear supernatant even in soils with low pH and high iron and aluminum concentrations. H3A-4 accurately predicts plant available nutrients and is a viable choice for commercial and laboratory settings due to its ease of use.展开更多
文摘Phosphorus loading and measurement is of concern on lands where biosolids have been applied. Traditional soil testing for plant-available P may be inadequate for the accurate assessment of P loadings in a regulatory environment as the reported levels may not correlate well with environmental risk. In order to accurately assess potential P runoff and leaching, as well as plant uptake, we must be able to measure organic P mineralized by the biotic community in the soil. Soils with varying rates of biosolid application were evaluated for mineralized organic P during a 112-day incubation using the difference between P measured using a rapid-flow analyzer (RFA) and an axial flow Varian ICP-OES. An increase in the P mineralized from the treated soils was observed from analysis with the Varian ICP-OES, but not with the RFA. These results confirm that even though organic P concentrations have increased due to increasing biosolid application, traditional soil testing using an RFA for detection, would not accurately portray P concentration and potential P loading from treated soils.
文摘The soil extractant, H3A, has undergone several iterations to extract calcium (Ca), iron (Fe), aluminum (Al), potassium (K), phosphorus (P), ammonium (NH4-N) and nitrate (NO3-N) under ambient soil conditions. Few soil extractants currently used by commercial and university soil testing laboratories can perform multi-nutrient extraction without over- or under-estimating at least one nutrient. Soil pH and plant root exudates have a strong influence on nutrient availability and H3A was developed to mimic soil conditions. Lithium citrate was previously used in the H3A formulation, but resulted in a cloudy supernatant in some samples, complicating laboratory analyses. In this study, we removed lithium citrate and compared the nutrients extracted from the modified (H3A-4) to the established (H3A-3) solutions. We found that the new extractant, H3A-4, produced a clear supernatant even in soils with low pH and high iron and aluminum concentrations. H3A-4 accurately predicts plant available nutrients and is a viable choice for commercial and laboratory settings due to its ease of use.
