Dados do Trabalho

Título

PHOSPHORUS AVAILABILITY IN RESPONSE TO THE APPLICATION OF PHOSPHATE ROCK MIXED WITH LEMON PEEL.

Resumo

Rock Phosphate (RP) is a natural phosphorus (P) source that can be an alternative to chemical fertilizers; unfortunately, their direct application to the soil is limited because the amount of P released is insufficient for supporting plant growth. Citrus peel wastes contain organic acids (OA), such as oxalic, citric, succinic, and malic; this OA has shown the ability to solubilize the fixed P in RP. This study investigates the influence of lemon peel (LP) on PR solubilization for P availability. For that, sorption isotherm and soil incubation were carried out. Fresh (F) and dry (D) LP at doses of 0.5, 1, and 2 g were added for both experiments. For sorption isotherm, triplicate samples of 1 g of PR were suspended in 20 mL of 0.01 M KCl media at 25°C from 0.5 to 72 h. RP without LP was used as a control. The incubation experiment was performed in an Andisol mixed with RP at equivalent field doses of 50-100-200 kg ha-1 and LP rates. The incubation was maintained for 60 days. In the sorption isotherm, the results showed that the P released from PR increased with the type of LP, and the dose was applied. As a result of cumulative available P release, the application of FLP, at doses of 0.5, 1, and 2 g, released about 5-fold, 33-fold, and 129-fold more P, respectively, compared with control. While DLP released approximately 124-fold, 342-fold, and 660-fold more P. For the incubation experiment, the results showed an increase in the P concentration due to the application of RP + LP compared with soil control. In contrast, no significant changes were observed between RP alone and RP mixed with LP. According to results from the sorption study, using LP could contribute to developing a "natural acidulation" of PR, improving its solubility to be applied directly in soils. Despite that, we did not observe a clear effect of LP on RP on P solubilization in soil incubation; this fact could be due to an insufficient amount of LP to the soil volume used.

Palavras-chave

P solubilization, citrus peel waste, phosphate rock.

Instituição financiadora

This work was supported by the FONDECYT Postdoctoral Project N° 3220546

Agradecimentos

This work was supported by the FONDECYT Postdoctoral Project N° 3220546