Struvite associated with organic matrix and silicon in phosphorus availability for maize and phosphorus fractionation in the rhizospheric soil

• Grant number: 25/09365-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2025
• End date: July 31, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Dirceu Maximino Fernandes
• Grantee: Luisa Duarte Mani Marques
• Host Institution: Faculdade de Ciências Agronômicas (FCA). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Struvite is a promising source of phosphorus (P) with gradual release in acidic environments, whose availability can be influenced by rhizospheric conditions and plant genotypic characteristics. However, its release may be limited in short-cycle crops, requiring strategies to enhance its efficiency, such as combining it with organic compounds or silicon. It is hypothesized that these combinations favor P uptake by increasing its availability in the rhizosphere and reducing fixation in the soil. The objective of the present study is to evaluate the efficiency of struvite, either alone or combined with an organic matrix and silicon, in supplying P to two maize genotypes, in comparison with a conventional phosphate source. The experiment will be conducted in pots using a medium-textured Oxisol, under a randomized block design (RBD) in a 2 × 6 factorial scheme, consisting of two distinct maize genotypes and six phosphate fertilizer treatments: (1) struvite; (2) struvite combined with organic compound (digestate); (3) struvite combined with silicon; (4) struvite combined with organic compound and silicon; (5) triple superphosphate; and (6) control (no P application). The evaluated parameters will include leaf area, stem diameter, shoot dry matter, shoot P content, resin-extractable P in non-rhizospheric soil, and P fractionation in the rhizosphere. Data will be subjected to tests for normality and homogeneity of variances, followed by analysis of variance and mean comparisons.