Phosphorus Availability for Irrigated Rice Cultivated Under No-Tillage and Different Phosphate Sources

Magali De Ávila Fortes,Algenor Da Silva Gomes,Rogério Oliveira De Sousa,Juliana Brito Da Silva Teixeira,Fabiana Schmidt,Walkyria Bueno Scivittaro,Thaís Antonili Veçozzi,Luis Henrique Gularte Ferreira

doi:10.5539/jas.v10n5p276

Abstract

The objective of this work was to evaluate the response of irrigated rice to phosphate fertilization using triple superphosphate (TSP) and Arad phosphate rock (APR), and the phosphate residual effects of upland crops in no-tillage system on the following rice crop. Also, it aimed to evaluate the efficiency of Mehlich-1 and anion exchange resin as soil P extractors. Two experiments were conducted in Albaqualf soil under irrigated conditions in the southern region of Rio Grande do Sul State. The experiments were designed as random blocks with four replications and the treatments were displayed as a 2 × 2 factorial (TSP and APR, with and without annual P application as TSP). No yield responses to phosphate were observed. Phosphate fertilization performed on upland crops (maize and soybeans) presented a residual effect on the rice crop even after four years of consecutive cropping under no-tillage. The extractors Mehlich-1 and AER were equally efficient in the evaluation of P availability for the rice crop. P content values obtained by both methods did show a significant correlation with accumulated plant P. The APR presents a similar performance as the TSP in regard to phosphate nutrition in irrigated rice when rotated with upland crops under no-tillage system.

Highlights

Soluble phosphate fertilizers are readily dissolved in the soil releasing high P concentrations, leading to higher P uptake and fast growth of plants
The objectives of this work were to evaluate the response of irrigated rice to phosphate fertilizer using triple superphosphate (TSP) and Arad phosphate rock (APR)
The grain yields were 100% and 50% higher than the control, respectively. These results indicate that upland crops respond better to phosphate fertilizer than irrigated rice

Summary

Introduction

Soluble phosphate fertilizers are readily dissolved in the soil releasing high P concentrations, leading to higher P uptake and fast growth of plants. These phosphate sources loose their efficiency over time since P adsorption occurs converting it to non-labile forms. Combinations of soluble and rock phosphate can consist in a good strategy for the supply of P to the irrigated rice cultivated as a single crop or in crop rotations (Ferreira et al, 2007). Some reports have shown a positive effect on rice grain yield after four years of phosphate rock (PR) fertilizer use, indicating a residual effect of P for the following crop (Gomes et al, 2005). It is possible that the residual effect remains for longer, but it was not possible to detect in this experiment

Objectives

Methods

Results

Conclusion