Does the removal of forest residues have an impact on the soil and plant microbiome related to C, N and P cycling? A metagenomic view

• Grant number: 18/20607-0
• Support Opportunities: Regular Research Grants
• Duration: April 01, 2020 - March 31, 2022
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Elke Jurandy Bran Nogueira Cardoso
• Grantee: Elke Jurandy Bran Nogueira Cardoso
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated researchers: Arthur Prudêncio de Araujo Pereira ; José Leonardo de Moraes Gonçalves

Abstract

The microbiome plays a fundamental role in forest ecosystems. In addition, it is responsible for ensuring nutrient cycling and maintaining soil and tree health. However, microbiome studies in Eucalyptus forests have not received much attention so far. Moreover, the idea of removing forest residues for energy generation is gradually being accepted in Brazil, but it is straightly opposite to the reasoning behind the minimum-till principle, a well-established forest practice in several regions of Brazil. There are no reports in the literature regarding the changes caused by the removal of forest residues on the taxonomic and functional diversity of the microbiome in tropical soils. The reduction in C soil levels, as well as in tree productivity are the principal effects reported in recent projects that adopted this practice. This reality allows us to formulate the following question: Are we trying to deconstruct the knowledge acquired over decades, in which the maintenance of forest residues has brought uncountable benefits to soil and plant health? To respond this question, we are going to follow-up a long-term experiment, installed with different levels of forest residue removals in a Eucalyptus grandis plantation, evaluating the metagenome through bioinformatics tools and identifying important drivers associated with soil nutrient cycling. Our main hypothesis is that forest residues removal reduces the taxonomic and functional diversity of the microbiome and promotes consistently decreases in C, N and P cycling. This experiment was installed in 2004 and reinstalled in 2012 (first and second rotation, respectively) at the Itatinga Experimental Station of Forest Sciences (ESALQ-USP) in a Yellow Latosol, with a medium sandy texture. In this experiment, soil samples from the organic (H-org., ~0-5 cm) and mineral (H-min., ~5-20 cm) horizon are going to be sampled in two seasons of the year (dry and rainy). Soil chemical and physical characterization, as well as the metabolic profile and microbial-enzymatic activity of the soil microbiome are going to be studied. The taxonomic and functional profile of the microbiome (bacteria and fungi communities) will be evaluated through large-scale sequencing, where the effect of the consecutive removal of forest residues will be evaluated to test our initial hypotheses. We hope to obtain a solid basis to transform the microbiome study into a tool for decision taking on the silvicultural practice, whether or not to remove the forest residues, in the light of a robust evaluation of the C, N and P cycling in this environment. (AU)