The Influence of Mechanical Composition and Mineral Composition of Calcareous Soil on Slope Farmland on Phosphorus Fixation

Abstract

Soil erosion on slope farmland causes the degradation of soil quality and eutrophication of water bodies due to the loss of phosphorus. In order to explore the influence of soil mechanical composition and mineral composition on phosphorus fixation, we selected calcareous soil on slope farmland in the Three Gorges Reservoir area as the research object and separated the samples on the basis of particle size. Next, we determined the content of different forms of phosphorus for each particle size, and then characterized and analyzed the mineral composition. The adsorption performance of each particle size was also studied. The results show that the calcareous soil on slope farmland has a high proportion of coarse fractions, and the carbonate minerals enriched in coarse fractions will fix a large amount of phosphorus and degrade soil quality. As slope farmland is prone to soil erosion, when the soil undergoes selective migration, the loss of fine fractions will increase the proportion of coarse fractions and aggravate soil quality degradation. Meanwhile, because of the large amount of phosphorus adsorbed by fine fractions, the available phosphorus is easily lost with fine fractions, leading to eutrophication of water bodies.

Nutritional content of pastures with phosphate fertilization in 2 calcareous soils

“…According to Han and Yin (2021), in calcareous soils, a high proportion of coarse fractions and calcium carbonate minerals in these fractions can fix large amounts of P, mainly via adsorption to the surface, causing them to precipitate mainly as dicalcium and tricalcium phosphates in high concentrations. However, according to Dilmaghani, Hemmaty and Naseri (2012), such soils have high levels of calcium carbonate equivalents and pH, leading to growth reduction, lower yields, nutrient deficiencies, and leaf chlorosis.…”

Phosphorus Sorption by Purple Soils in Relation to Their Properties: Investigation, Characterization, and Explanation

“…It is quite feasible that water leaching through the soils would have a high phosphate content. Such soil conditions are considered to be a harbinger of soil degradation from the perspective of soil ecology [52,53]. Overloaded foreign P induces an initial reaction with soil, which significantly decreases both the amount and the rate of sorption of subsequent fertilizers.…”

Feldspathic sandstone as an emerging soil stabilizer for aeolian sand in the Mu Us Sandy Land: insights into particle size composition

“…Despite being an object of land governance, feldspathic sandstone resources have not yet been exploited and utilized. Based on the knowledge of soil erosion mechanisms and the practice of sandy land governance, the occurrence of soil erosion is in close association with the particle size composition of surface soil [15][16][17][18][19][20] . As feldspathic sandstone and aeolian sand are respectively compacted and loose in texture, the use of feldspathic sandstone as a sandy soil stabilizer is expected to reverse the traditional idea of controlling deserti cation to promoting soil formation.…”