Intercropped silviculture systems, a key to achieving soil fungal community management in eucalyptus plantations.

Caio T C C Rachid,Guilherme M Chaer,Alexandre S Rosado,Raquel Silva Peixoto,Fabiano C Balieiro,James M Tiedje,Eduardo S Fonseca,Andrey M Yurkov

doi:10.1371/journal.pone.0118515

Abstract

Fungi are ubiquitous and important contributors to soil nutrient cycling, playing a vital role in C, N and P turnover, with many fungi having direct beneficial relationships with plants. However, the factors that modulate the soil fungal community are poorly understood. We studied the degree to which the composition of tree species affected the soil fungal community structure and diversity by pyrosequencing the 28S rRNA gene in soil DNA. We were also interested in whether intercropping (mixed plantation of two plant species) could be used to select fungal species. More than 50,000 high quality sequences were analyzed from three treatments: monoculture of Eucalyptus; monoculture of Acacia mangium; and a mixed plantation with both species sampled 2 and 3 years after planting. We found that the plant type had a major effect on the soil fungal community structure, with 75% of the sequences from the Eucalyptus soil belonging to Basidiomycota and 19% to Ascomycota, and the Acacia soil having a sequence distribution of 28% and 62%, respectively. The intercropping of Acacia mangium in a Eucalyptus plantation significantly increased the number of fungal genera and the diversity indices and introduced or increased the frequency of several genera that were not found in the monoculture cultivation samples. Our results suggest that management of soil fungi is possible by manipulating the composition of the plant community, and intercropped systems can be a means to achieve that.

Highlights

Planted forests represent a cheap and renewable source of raw material for industry and reduce the pressure on native vegetation [1]
Our goal was to evaluate the soil fungal community using pyrosequencing over two consecutive years
The soil is classified as Haplic Solonetz according to the FAO/UNESCO system of soil classification (Planosolo háplico, according to the Brazilian Soil Taxonomy), characterized by sandy topsoil (~90% sand), low cation exchange capacity (CEC), and low organic matter and nutrient contents

Summary

Introduction

Planted forests represent a cheap and renewable source of raw material for industry and reduce the pressure on native vegetation [1]. These forests are an important component of the economy in many countries. In Brazil, 6.5 million hectares of forest is cultivated, playing an important economic role and a source of employment for millions of citizens. Eucalyptus and Pinus are the genera most commonly used for silviculture in Brazil and are the most important. Soil Fungal Community in Eucalyptus and Acacia Mixed Plantations. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Objectives

Methods

Results