Humic acid-phosphate fertilizer interaction and extractable phosphorus in soils of contrasting texture

• Published in: Ciência agronômica Vol. 49; no. 1; pp. 32 - 42
• Main Authors: Rosa, Sara Dantas, Silva, Carlos Alberto, Maluf, Henrique José Guimarães Moreira
• Format: Journal Article
• Language: English; Portuguese
• Published: Fortaleza Universidade Federal do Ceará, Centro de Ciências Agrárias 01.01.2018; Universidade Federal do Ceará
• Subjects: Agrochemicals; AGRONOMY; Extratores de P do solo; Fertilizers; Fosfatos naturais; Humic acids; Ion exchange resins; Organic matter; Organic soils; pH do solo; pH effects; Phosphates; Phosphorus; Soil mixtures; Soil properties; Substâncias húmicas; Extractors of soil P; Soil pH; Phosphate rocks; pH do solo; Substâncias húmicas; Fosfatos naturais; Humic substances; Extratores de P do solo
• ISSN: 1806-6690; 0045-6888; 1806-6690
• DOI: 10.5935/1806-6690.20180004

Extractable phosphorus (P) in soil depends on soil test employed, reactivity of fertilizer and interaction of P added to the soil properties, including organic matter. The aim of this paper was to assess the contents of P extracted from Red Latosol (LVd) and Quartzarenic Neosol (RQ) samples, incubated with 0; 5; 10; 50 or 100 mg kg-1 C-humic acid (C-HA) and 400 mg kg-1 of P, via Araxá phosphate rock (AP), Bayóvar reactive phosphate rock (BP) or single superphosphate (SS). Thus, it was adopted a five (C-HA concentrations) x three (P sources) factorial arrangement, using a randomized block design with three replications. The mixtures of soil, C-HA concentrations and P sources were incubated for 60 days; in sequence, the soil P was extracted by solutions of Bray-1, Mehlich-1 and Mehlich-3 and mixed ion exchange resin. In the LVd and RQ samples, the addition of C-HA reduced extractable phosphorus when the source was AP and BP. The levels of extractable P increased with the application of C-HA in RQ when the source was SS; the average concentration of 50 mg kg-1 C-AH provided the maximum extractable P by Bray-1, Mehlich-3 and mixed resin. The pH is the chemical attribute that most influence the extractable P content of the soil.