Arbuscular mycorrhizal fungi on the biomass and nutrition of Urochloa decumbens at different soil densities

Luciane Reis Sales,Marco Aurélio Carbone Carneiro,Geanderson Nascimento Da Silva,Raphael Henrique Da Silva Siqueira,Valdemar Faquin

doi:10.1590/s0100-204x2018000800009

Abstract

Abstract: The objective of this work was to evaluate the influence of arbuscular mycorrhizal fungi (AMF) on the accumulation of shoot and root biomass and on the nutrient contents of Urochloa decumbens grown in soils with different densities. The experiment was carried out in a randomized complete block design, in a 4x2 factorial arrangement: four soil densities (1.0, 1.2, 1.4, and 1.6 kg dm-3) with and without inoculation of AMF, with four replicates. The biomass accumulation (dry matter weight of shoot and roots) and macro- and micronutrient contents of U. decumbens were determined at different soil densities. The mycorrhizal colonization of the plants was evaluated, and the number of mycorrhizal spores present in the soil was determined. The biomass accumulation of shoot and roots and macro- and micronutrient contents, as well as the number of mycorrhizal spores in the soil, were negatively affected by the increase in soil density. Only root biomass increased with AMF inoculation. There was no interaction between soil density and inoculation for shoot and root biomass accumulation. Arbuscular mycorrhizal fungi influence the accumulation of biomass in the roots and of N and Ca contents in the shoots of Urochloa decumbens even at the highest soil densities.

Highlights

The conversion of large areas of natural vegetation for animal production is one of the major causes of degradation in rural areas in Brazil
The biomass accumulation of shoot and roots was affected by soil density
Only root dry biomass accumulation was affected by arbuscular mycorrhizal fungi (AMF) soil inoculation, and there was no interaction between the factors soil density and AMF inoculation on shoot and root biomass accumulation

Summary

Introduction

Resistance to root penetration, decrease porosity, limit pore continuity and soil aeration, and impair water infiltration and hydraulic conductivity (Valicheski et al, 2012; Farias et al, 2013). Different management practices, such as subsoiling and cover plants, are used to break down compacted soil layers. Among the used cover plants, Urochloa decumbens (Stapf) R.D.Webster (Syn. Brachiaria decumbens Stapf) stands out due to its deep root system that is resistant to drought and to its very good response to mycorrhizal colonization with arbuscular mycorrhizal fungi (AMF), according to Carneiro et al (1999)

Objectives

Methods

Results