Artículos de revistas
Agronomic evaluation of calcined crandallite from three Brazilian phosphate deposits
Fecha
2008Registro en:
COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS, v.39, n.3/Abr, p.559-573, 2008
0010-3624
10.1080/00103620701826852
Autor
FRANCISCO, Eros Artur Bohac
PROCHNOW, Luis Ignacio
TOLEDO, Maria Cristina Motta de
PEREIRA, Joao Paulo
Institución
Resumen
Samples from the weathering mantle containing crandallite of three Brazilian phosphate deposits, Tapira, Catalo, and Juqui, were characterized, calcined, and agronomically evaluated. The calcination process increased total phosphorus (P) and neutral ammonium citrate soluble (NAC) P contents of all samples. The NAC solubility of original Tapira, Catalo, and Juqui was about 5% of total P, whereas for calcined samples it was 54, 16, and 53%, respectively. In a greenhouse study, rates of P were applied at 0, 10, 20, 40, 80, and 120mg P kg(-1) from the calcined materials and MCP (monocalcium phosphate) to an Ultisol cropped with upland and flooded rice for 65 days. The results showed that the calcined P samples increased dry-matter yield and P uptake with increasing rates of P applied for both crops. Tapira and Juqui were more effective for flooded than for upland rice. The calculated values of relative agronomic effectiveness of Tapira, Catalo, and Juqui with respect to MCP were 57, 48, and 53% in dry-matter yield for upland rice and 64, 50, and 69% for flooded rice, respectively.