A method for grading phosphorus in calcareous purple soil

Abstract

The invention discloses a calcareous purple soil phosphorus grading method. The calcareous purple soil phosphorus grading method comprises the steps that 1, deionized water is adopted to extract water-soluble organic phosphorus and water-soluble inorganic phosphorus in a soil sample; 2, anion exchange resin is adopted to extract resin-soluble organic phosphorus and inorganic phosphorus in the sample; 3, sodium bicarbonate, ammonium acetate and ammonium fluoride are adopted to extract active organic phosphorus, dicalcium type calcium phosphate, octacalcium type phosphate and aluminum phosphate in the sample, and chloroform is adopted to extract microbial-biomass phosphorus; 4, sodium hydroxide and sodium citrate are adopted to extract slow organic phosphorus, iron type phosphorus and occluded phosphorus in the sample; 5, HCl and ultrasonic waves are adopted to extract chronic organophosphate and organic phosphorus and inorganic phosphorus in aggregate in the sample, and the stable organophosphorus in soil is calculated; 6, an ICP method is adopted to extract residual state phosphorus. The method details grading of the phosphorus in calcareous purple soil, the grading is more scientific and comprehensive, and the grading accuracy and reliability are ensured by selecting different chemical extraction reagents and extraction sequences.

Description

technical field [0001] The invention relates to soil phosphorus grading, in particular to a phosphorus grading method specially for calcareous purple soil, and belongs to the technical field of soil phosphorus grading. Background technique [0002] Soil phosphorus is not only an essential macronutrient for plant growth, but also an important factor that causes agricultural non-point source pollution and water eutrophication. It plays an important role in maintaining the balance and sustainable development of agricultural ecosystems. It is of great significance to reveal the status of soil phosphorus supply and loss by using appropriate soil phosphorus classification methods to study the migration, transformation and availability of phosphorus forms in soil. [0003] Phosphorus in soil is mainly divided into organic phosphorus and inorganic phosphorus, of which inorganic phosphorus is the main form. Inorganic phosphorus in soil mainly includes orthophosphate and pyrophospha...

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Problems solved by technology

These two methods are mainly aimed at acidic or neutral soils, but they cannot be graded well for calcareous soils, especially phosphorus in calcareous purple soils.

This is due to the fact that the calcareous purple soil is loose, has good air permeability, and is mostly loam or clay loam. The soil phosphorus has the characteristics of "high organic phosphorus content, high organic-inorganic phosphorus composite degree, and high phosphorus form diversity". Traditional classification methods cannot effectively separate phosphorus forms, especially phosphorus forms in organic-inorganic complexes, which limits the study of phosphorus cycle in calcareous purple soils

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