NITRATE AND POTASSIUM DYNAMICS IN PROFILES OF SOILS CULTIVATED WITH FERTIGATED SUGARCANE CROPS

Valdeci Calixto Da Silva Filho,Francisco De Brito Melo,Alzeneide Da Silva Lopes,Valdenir Queiroz Ribeiro,Aderson Soares De Andrade Júnior

doi:10.1590/1983-21252019v32n408rc

Valdeci Calixto Da Silva Filho, Francisco De Brito Melo + Show 3 more

Open Access

https://doi.org/10.1590/1983-21252019v32n408rc

Copy DOI

Journal: Revista Caatinga	Publication Date: Dec 1, 2019
License type: CC BY 4.0

Affiliation: Universidade Federal do Piauí

Abstract

ABSTRACT The objective of this study was to evaluate the distribution of NO3 - and K+ in the profile of soils cultivated with sugarcane crops, after application of different nitrogen (N) and potassium (K2O) rates via subsurface drip fertigation, in Teresina, PI, Brazil. The experiment was conducted at the experimental area of Embrapa Meio-Norte, using a randomized block design with four replications. The treatments were arranged in split plots, with N+K2O rates (60+120, 180+120, 120+60, 120+180, and 120+120 kg ha-1 of N + K2O, respectively) in the plots, and soil layers (0.0-0.2, 0.2-0.4, and 0.4-0.6 m), for quantification of NO3- and K+ concentrations in the soil, in the subplots. The soil of the experimental area was a Typic Hapludult of sandy-loam texture. The distribution of nitrate (NO3-) and potassium (K+) in the soil layers after the N+K2O applications were evaluated. The NO3- and K+ concentrations in soils under sugarcane crops in the plant crop cycle is higher at the beginning and at the end of the cycle, respectively. The NO3 - and K+ concentrations in the soil solution are dependent on the evaluation time, soil layer, and N and K2O rates applied via fertigation. The highest concentrations of NO3- (264 mg L-1) and K+ (377 ppm) were found in the 0.0-0.2 m soil layer. No leaching of NO3- or K+ to deepest soil layers (>0.4 m) was found.

Highlights

The use of traditional soil fertilization for sugarcane crops is common due to its practicality and lower technical requirement, which may lead to disordered applications
This practice is characterized by applications of high fertilizer rates at low frequencies, causing risk of nutrient leaching to areas with no root systems, especially nitrate (NO3-) and potassium (K+) (VITTI et al, 2005)
Oliveira et al (2001) evaluated the effect of the application of different N rates on the leaching of NO3- in an Oxisol (Latossolo Amarelo) cultivated with sugarcane crops and found differences in NO3concentrations in the soil solution at depths of 0.3, 0.6, and 0.9 m according to the treatments and sampling times, and found increases in NO3- contents in all evaluated soil layers as the N rates applied was increased, which is in agreement with the results found in the present study

Summary

Introduction

The use of traditional soil fertilization for sugarcane crops is common due to its practicality and lower technical requirement, which may lead to disordered applications. This practice is characterized by applications of high fertilizer rates at low frequencies, causing risk of nutrient leaching to areas with no root systems, especially nitrate (NO3-) and potassium (K+) (VITTI et al, 2005). Nutrient uptake by plants, such as sugarcane, is limited by soil, temperature, solar radiation, and precipitation (OLIVEIRA et al, 2011). The Brazilian northeastern coast presents rainfall concentrated within four months, hindering the crops' productive capacity and the plants' efficiency in absorbing available soil water and nutrients (SANTOS et al, 2009)

Objectives

Methods

Results

Conclusion