Phosphorus

About: Phosphorus is a research topic. Over the lifetime, 53120 publications have been published within this topic receiving 939731 citations. The topic is also known as: element 15 & P.

Comparison of Methods for Determining Critical Concentrations of Soil Test Phosphorus for Corn

Abstract: Critical concentrations of soil-test P (STP) are used to identify soils where response to P fertilization should be expected. There is, however, little agreement concerning the methods that should be used to identify critical STP concentrations. This study compares the efficacy of critical STP concentrations generated by using various methods. Twenty-five P fertilization trials with corn (Zea mays L.) were established in Iowa. Available soil P at each site was estimated by the Bray-P 1 , Mehlich-3, and Olsen extractants (...)

Phosphate Mineral Reactivity and Global Sustainability

Abstract: Phosphorus is a unique element. It is the limiting nutrient controlling biological productivity in many terrestrial and marine environments. When in excess, however, dissolved phosphate leads to uncontrollable biological growth and water-quality problems through a process called eutrophication. The use of phosphate minerals and their products as fertilizers has increased tremendously global food production; it would not be possible to feed the current world population without phosphate fertilizers. Yet phosphate is a limited global resource; current estimates suggest economic phosphorus supply may be severely depleted over the next 100 years. Nevertheless, mineralogists and geochemists have invested little time investigating phosphate mineral stability, reactivity, and transformations. This issue attempts to bring phosphates to the forefront of our scientific endeavours.

A Simplified Soil and Plant Phosphorus Model: II. Prediction of Labile, Organic, and Sorbed Phosphorus

Abstract: Surface samples and soil chemical, physical and taxonomic data for 78 soils from the continental U.S. and Puerto Rico were obtained from the U.S. Soil Conservation Service National Soil Survey Lab. Phosphorus was extracted with the following: NHF + HCl (Bray 1 P), NaHCO (Olsen P), HCl + HSO (North Carolina P), and anion exchange resin (labile P). Organic P and an index of fertilizer P sorption were also measured. Soils were divided into three groups based on soil taxonomy and weathering. Regression analysis was used to obtain equations to predict labile P, organic P, and a P sorption index from soil chemical and physical properties. Labile P was related to extractable P; organic P to total N and pH; and P sorption to clay, CaCO, labile P, and base saturation. These parameters accounted for up to 84% of labile P variation, 64% of organic P variation, and up to 78% of P sorption variation. Although the equations are empirical, independent variables chosen in the stepwide regression were consistent with P mineralization and sorption relationships previously reported. These relationships were tested using independent data sets. They can be used to generate inputs for the soil P component of the Erosion-Productivity Impact Calculator crop management model from soil test P and data available in U.S. Soil Conservation Service/State Agricultural Experiment Station Soil Survey Investigation Reports.

A suggested fractionation scheme of inorganic phosphorus in calcareous soils

Abstract: On the basis of a critical review on conventional fractionation schemes of inorganic phosphate and further study of chemical behaviors of Ca-P and Fe-P in calcareous soils, a systematic scheme for the separation of soil inorganic phosphates in calcareous soils is suggested. In the scheme calcium phosphate is classified into dicalcium phosphate, octacalcium phosphate and apatite types, and Ca2-P is extracted by NaHCO3 solution, Ca8-P by NH4Ac, Al-P by NH4F, Fe-P by NaOH-Na2CO3, occluded-P by Na3Cit-Na2S2O4-NaOH, and Ca10-P by H2SO4. Synthetic phosphates prepared of which the chemical and physical assay show good consonance with the theoretical value were used in experiment, the recovery rates of the phosphates added into the calcareous soils by specific extractants is at the range of 85–99%.