Phosphorus adsorption after drainage in two soil classes

Juliana Brito Da Silva Teixeira,Marcos Lima Campos Do Vale,Rogério Oliveira De Sousa

doi:10.1590/0034-737x201865020012

Abstract

ABSTRACT Lowland soils, seasonally flooded for rice cultivation, feature alternate oxidation and reduction conditions, which determine intense modifications in the soil mineral solid phase and in the dynamics of highly reactive elements, such as phosphorus. This study aimed to evaluate the effect of drainage of two lowland soils (Albaqualf and Argiaquoll) after a flooding period on the maximum phosphorus adsorption capacity (MPAC). The experiment was conducted in a greenhouse, and the system factor was composed of two levels: 1) flooded soil for 63 days, followed by drainage, and then humidity remained at 16% for 184 days; 2) soil moisture maintained at 16% throughout the trial period. After drainage, soil samples were collected at 0, 36, 96 and, 184 days for MPAC determination, which was performed by the adjustment of adsorption isotherms according to the Langmuir model. The behavior of MPAC after soil drainage was different for both soil classes evaluated. An immediate reduction of maximum phosphorus adsorption capacity was seen after drainage in the case of Albaqualf, while for Argiaquoll, there was a tendency to maintain higher values of MPAC after drainage, with subsequent reduction. Soil drainage after a flooding period increases de maximum phosphorus adsorption capacity, and this effect remains for approximately 163 days in Argiaquoll and 121 days in Albaqualf soils.

Highlights

A high soil use efficiency is one of the most important factors to maximize the yield potential of agricultural areas
The long period of anaerobiosis observed in soils cultivated with rice under flooding promotes a series of changes that can negatively affect the agricultural activities that follow
For Albaqualf, the stabilization of Eh values were observed at eight days, while for Argiaquoll, the stabililization was observed at 29 days of flooding with the smallest Eh values

Summary

Introduction

A high soil use efficiency is one of the most important factors to maximize the yield potential of agricultural areas. Soil aptitude to rice cultivation under flooding can make it difficult to establish such systems. The long period of anaerobiosis observed in soils cultivated with rice under flooding promotes a series of changes that can negatively affect the agricultural activities that follow. Such changes result from soil microorganism metabolic adaptation to low oxygen conditions, and among nutrients, phosphorus (P) is the most unstable during this process. P is not directly involved in the soil redox reactions, it is affected by flooding because it is chemically linked to oxidized substances, such as iron and manganese oxides (Shahandeh et al, 2003)

Objectives

Methods

Results