Soil P Diffusion and Availability Modified by Controlled-Release P Fertilizers

Abstract

Slow-release fertilizers have been proposed as tools to increase P fertilizer use efficiency in tropical acidic soils with high P adsorption, low P availability, and mobility. However, results have been controversial since soil diversity and the fertilizer itself may influence the results, which is not completely understood. Soil P diffusion and availability were studied in soils with different P fertilization histories, where triple superphosphate (TSP) and single superphosphate (SSP) coated with a polymer or with humic acid and complexed with humic acid were applied under laboratory conditions. No difference in soil P availability and diffusion was observed between humic acid-complexed, polymer, and humic acid-coated TSP and conventional TSP. For SSP, soil P availability was 15 to 30% lower in the region of application for the polymer and 0 to 16% for the humic-coated fertilizer. For the polymer-coated SSP, P diffusion was lower in some soils. With both base fertilizers, the soil adsorption capacity was more determinant of P diffusion than the protection of the fertilizers. Coating P fertilizers with polymer and complexing or coating the fertilizer with humic acid does not increase P availability or diffusivity in soil since these processes are driven mainly by the soil characteristics. Therefore, the potential of these controlled-release P fertilizers in increasing P use efficiency is low.

Micronutrients in coated phosphate fertilizer improve precision distribution and nutrient use efficiency of soybean

“…Expressive P availability was observed in the region where the granules were deposited (5 mm), with a significant reduction in the subsequent areas (25 and 45 mm), regardless of the incubation time. Previous studies have reported similar patterns (Degryse et al., 2013; Lombi et al., 2006; Montalvo et al., 2014; Nunes et al., 2022; Volf & Rosolem, 2021). In addition, the reduced movement of P can be explained by a combination of adsorption reactions between P and soil colloids and its low movement, mainly by diffusion (Novais et al., 2007; Sample et al., 1980; Tiecher et al., 2012).…”

“…Previous studies have reported similar patterns (Degryse et al, 2013;Lombi et al, 2006;Montalvo et al, 2014;Nunes et al, 2022;Volf & Rosolem, 2021). In addition, the reduced movement of P can be explained by a combination of adsorption reactions between P and soil colloids and its low movement, mainly by diffusion (Novais et al, 2007;Sample et al, 1980;Tiecher et al, 2012).…”

Managing Phosphorus Availability from Organic and Inorganic Sources for Optimum Wheat Production in Calcareous Soils

“…High nutrient uptake was observed in the plots treated with both FYM and mineral fertilizers. Ghosh et al [30] suggested that coating P fertilizer granules with layers of organic materials results in higher absorption and efficiency in the use of P compared with uncoated fertilizer [31]. Organic acids released during the decomposition process are good chelating agents for P and increase its availability from applied P fertilizers [32].…”

Effect of Fast Dissolved Phosphorus Fertilizer on the Growth, Seed Product, and Phosphorus Uptake Efficiency of Soybean (Glycine max L.)

“…The efficiency of P fertilization in various crops has been studied by several researchers. Volf & Rosolem (2021) studied the use of Triple Super Phosphate (TSP) and Super Phosphate (SP) coated with humic acid to control nutrient release and it was observed that there was no significant increase of P use efficiency on both P-fertilizers. Devi et al (2012) observed the efficiency of P fertilization on soybean by applying different sources of P fertilizer.…”