Combined Effects of Soil Biotic and Abiotic Factors, Influenced by Sewage Sludge Incorporation, on the Incidence of Corn Stalk Rot

PLoS One. 2016 May 13;11(5):e0155536. doi: 10.1371/journal.pone.0155536. eCollection 2016.

Abstract

The objectives of this study were to evaluate the combined effects of soil biotic and abiotic factors on the incidence of Fusarium corn stalk rot, during four annual incorporations of two types of sewage sludge into soil in a 5-years field assay under tropical conditions and to predict the effects of these variables on the disease. For each type of sewage sludge, the following treatments were included: control with mineral fertilization recommended for corn; control without fertilization; sewage sludge based on the nitrogen concentration that provided the same amount of nitrogen as in the mineral fertilizer treatment; and sewage sludge that provided two, four and eight times the nitrogen concentration recommended for corn. Increasing dosages of both types of sewage sludge incorporated into soil resulted in increased corn stalk rot incidence, being negatively correlated with corn yield. A global analysis highlighted the effect of the year of the experiment, followed by the sewage sludge dosages. The type of sewage sludge did not affect the disease incidence. A multiple logistic model using a stepwise procedure was fitted based on the selection of a model that included the three explanatory parameters for disease incidence: electrical conductivity, magnesium and Fusarium population. In the selected model, the probability of higher disease incidence increased with an increase of these three explanatory parameters. When the explanatory parameters were compared, electrical conductivity presented a dominant effect and was the main variable to predict the probability distribution curves of Fusarium corn stalk rot, after sewage sludge application into the soil.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cluster Analysis
  • Electric Conductivity
  • Fusarium / physiology*
  • Hydrogen-Ion Concentration
  • Logistic Models
  • Models, Theoretical
  • Phylogeny
  • Plant Diseases / microbiology*
  • Probability
  • Sewage
  • Soil Microbiology*
  • Soil*
  • Zea mays / microbiology*

Substances

  • Sewage
  • Soil

Grant support

Financial support for this research was provided by Project 061102237-04 “Impacto ambiental do uso agrícola do lodo de esgoto” from Empresa Brasileira de Pesquisa Agropecuária (Embrapa). R. Ghini, C. A. Silva and W. Bettiol are recipients of research fellows 304189/2013-8, 303899/2015-8 and 305818/2015-5, respectively, from “Conselho Nacional de Desenvolvimento Científico e Tecnológico” (CNPq).