Phosphorous fractions in weathered tropical soils after application of conventional and alternative P fertilizers

Authors: DA SILVA SANDIM, ALINE - Sao Paulo State University (UNESP); RODRIGUES DA SILVA, LUCAS - Sao Paulo State University (UNESP); FERNANDES DEUS, ANGELICA - Sao Paulo State Agency For Agribusiness Technology (APTA); Penn, Chad; BULL, LEONARDO - Sao Paulo State University (UNESP)

Submitted to: Journal of Soil Science and Plant Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/2/2023
Publication Date: 8/14/2023
Citation: da Silva Sandim, A., Rodrigues da Silva, L.J., Fernandes Deus, A.C., Penn, C.J., Bull, L.T. 2023. Phosphorous fractions in weathered tropical soils after application of conventional and alternative P fertilizers. Journal of Soil Science and Plant Nutrition. https://doi.org/10.1007/s42729-023-01426-w.
DOI: https://doi.org/10.1007/s42729-023-01426-w

Interpretive Summary: Soil phosphorus (P) is one of the mostly limiting nutrients for crop production. However, P fixation by highly weathered soils makes it unavailable to growing plants, reducing agronomic production and increasing costs. Production of highly soluble commercial fertilizer is expensive and consumes large amounts of energy. This study examined the ability of by-product and alternative P fertilizers with regard to solution P supply and diffusion within the soil. Two different soils were tested at two pH levels with four different P sources and a control receiving no P. Results showed that two of the by-product P sources were able to diffuse through the soil as well as the conventional P fertilizer. Increasing soil pH enhanced the solubility and diffusion of the alternative P sources. This study showed that less-expensive P by-products may adequately serve as P fertilizers, which would conserve resources.

Technical Abstract: Purpose: Phosphorus (P) is a limiting nutrient for agriculture globally. This study aims to investigate the potential of alternative P sources to improve P efficiency in weathered tropical soils of the Brazilian Cerrado region. Methods: We evaluated P fractions in two soil types a tropical Ferralsol and an Arenosol, both with different maximum adsorption capacities of phosphorus, fertilized with various phosphate sources. The experiment followed a randomized block design, using a factorial scheme of 2 × 4 for each soil, with and without limestone correction, and four fertilizer types: two precipitated phosphorus sources, reactive phosphate rock, triple superphosphate, and a control group. The study was conducted under laboratory conditions, and we assessed soil and fertilizer chemical properties and phosphorus fractions and diffusion. Results: Our findings indicate that precipitated phosphorus exhibited similar or better behavior in terms of availability and diffusion than triple superphosphate, despite its lower water solubility. After lime application, we observed an increase in moderately labile P fractions in the soil where precipitated phosphorus source was applied. Furthermore, we found that soil chemical properties (soil pH, soil organic matter, cation exchange capacity, and potential acidity) influence P fractions in weathering tropical soils. Conclusion The results suggest that Precipitated phosphorus source is a promising alternative P source that could potentially improve P efficiency in weathered tropical soils. Our findings highlight the need to consider soil chemical properties in the P dynamics of these soils.