Growth and nutrient contents in lowland rice due to phosphorus and potassium fertilization

André Fróes De Borja Reis,Rodrigo Estevam Munhoz De Almeida,Adriano Stephan Nascente,Aloísio Freitas Chagas Júnior

doi:10.1590/1983-40632018v4850666

Abstract

ABSTRACT In order to reach an optimum and sustainable production, growers must know the fertilizing potassium (K) and phosphorous (P) application rates. The present study aimed to determine the rice development in response to combined rates of P and K, on Plinthaquults (380-400 g kg-1 of clay), under high and low fertility conditions, in the tropical lowland plain of the Araguaia river, Brazil. Three field experiments were performed, each one consisting of a completely randomized factorial block design, with three replications. Treatments included a combination of six K2O rates (0 kg ha-1, 30 kg ha-1, 60 kg ha-1, 90 kg ha-1, 120 kg ha-1 and 150 kg ha-1) with six P2O5 rates (0 kg ha-1, 30 kg ha-1, 60 kg ha-1, 90 kg ha-1, 120 kg ha-1 and 150 kg ha-1). No interaction effect between P and K rates was observed for the evaluated variables in any fertility level/year. Phosphorous application under low fertility conditions, as well as K under high fertility conditions, affect overall crop nutrition, tillering capacity, yield components and grain yield of lowland rice, though no effects were observed due to the P application in high fertility soils and K in low fertility soils. Under high fertility conditions, the grain yield increment rate due to the K application was 4.04 kg ha-1, whereas in the low fertility areas, such as recently cleared fields, a maximum yield of 7,161 kg ha-1 was achieved by applying 140 kg ha-1 of P.

Highlights

Rice (Oryza sativa) is one of the most important grains for human consumption throughout the world (Nascente et al 2013, Heinemann et al 2017)
In Brazil, as in other world regions, this crop can be grown in two ecosystems: lowland and upland (Fageria et al 2003)
There were no interactions between the P and K fertilizer rates for leaf content of N, P, K, Ca, Mg, Cu, Fe, Mn, Zn and biometric parameters, such as tillering, yield components and grain yield of lowland rice, in tropical floodplains; 2

Summary

Introduction

Rice (Oryza sativa) is one of the most important grains for human consumption throughout the world (Nascente et al 2013, Heinemann et al 2017). In Brazil, as in other world regions, this crop can be grown in two ecosystems: lowland and upland (Fageria et al 2003). Rice can be cultivated in floodplains with water control and in not systematized soils irrigated by rainwater or by raising the water table. The available area for sustainable irrigation in Brazil is about 30 million ha, 50.6 % of which could. Less than 3 million ha of these areas are under cultivation (Fageria et al 2015). This is one of the largest land areas available in the world to produce food and fiber

Objectives

Methods

Conclusion