Phosphate fertilization for rice irrigated in soils with different phosphorus adsorption capacities

ABSTRACT

This work evaluated the response of irrigated rice fertilized with two sources of phosphorus in paddy soils with different phosphorus adsorption capacities. Also, it evaluated the phosphorus availability predictive ability for irrigated rice. We studied two soils with different maximum phosphorus adsorption capacities (MPAC), a Planosol (low MPAC) and a Gleysol (high MPAC). The experiment was conducted in a greenhouse evaluating two sources (rock phosphate and triple superphosphate) and six levels (0, 10, 20, 40, 80 and 160 mg kg⁻¹) of phosphorus. Phosphorus contents in the soil, in the soil solution and the dry matter weight of the plants were evaluated. Phosphorus contents in the soil were analyzed by extractors Mehlich-1 and Anion Exchange Resin. The Mehlich-1 extractor and the Anion Exchange Resin methods were equivalent in the ability to predict the availability of phosphorus for rice in both soils, with high and low MPAC. The highest response rates of rice to fertilization were 10 mg kg⁻¹ and 80 mg kg⁻¹ of phosphorus in the Planosol and Gleysol, respectively. This proves the hypothesis of the work that soils with higher MPAC require higher doses of phosphate to reach maximum dry matter production.

KEYWORDS:

• Phosphorus
• paddy soils
• maximum phosphorus adsorption capacity
• rock phosphate
• Mehlich
• resin

Acknowledgements

The authors would like to thank coordination for the improvement of higher education personnel (CAPES) and national council for technological research and development (CNPq) for the financial support of the research.

Disclosure statement

No potential conflict of interest was reported by the author.