Application of superphosphate complexed with humic acid in an area of sugarcane

Resumo

In tropical soils, the efficiency of phosphorus (P) fertilization is low, due to P adsorption on the surface of the
clay. Superphosphate complexed with humic acid (SSP+HA) is presented as an alternative for improving P use efficiency and
crop yields. The aim of this study was to investigate SSP+HA performance in sugarcane production including increases in plant
dry matter (DM) and P content. The experiment was conducted with two sources of P (simple superphosphate – SSP, SSP+HA)
and five doses (0, 45, 90, 135 and 180 kg ha-1 P2O5
). The dose of 135 kg ha-1 P2O5
was used to explain the residual effect of P,
collecting soil samples from the plant cane and first ratoon. Stalk, top and root samples were collected to determine DM and
P content; both variables were used to calculate the P assimilation efficiency (PaE). Results showed that the application of
SSP increased the DM and P content of the plants, with superior performance compared to SSP+HA. PaE was greater under
SSP+HA, indicating that P was metabolized more efficiently; however this did not reflect in an increase in DM. AThe P rates
increased the sugarcane yield in cane plant, but there was no effect of P applied in the first ratoon due to the residual effect of
P applied in planting. SSP presented superior performance compared to SSP + SH in sugarcane planting. Further research is
needed to better demonstrate the effect of SSP+HA on the absorption and translocation of P.