Greenhouse gas emission associated with soil microbiology in areas under energy cane management

• Grant number: 18/04992-1
• Support type: Scholarships in Brazil - Post-Doctorate
• Effective date (Start): June 01, 2018
• Effective date (End): May 31, 2020
• Field of knowledge: Agronomical Sciences - Agronomy
• Principal Investigator: João Luís Nunes Carvalho
• Grantee: Mara Regina Moitinho
• Home Institution: Centro Nacional de Pesquisa em Energia e Materiais (CNPEM). Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brasil). Campinas , SP, Brazil

Abstract

Agriculture is a major emitting source of gases into the atmosphere, contributing significantly to the increase in the greenhouse effect. The accelerated demand of the sugarcane sector has driven the development of measures aimed at reducing the impact of agricultural activities on the environment without reduction in sugarcane productivity. In this context, energy cane has been revolutionizing this sector with the proposal of a raw material that presents a higher fiber content and high amount of biomass for producing the 2nd generation ethanol (2G), which presents a great potential to reduce ethanol production costs and adverse impacts of climate change. Assuming that rhizome and a high biomass production are the major differentials of this crop, the aim of this project is to evaluate the emission of CO2, N2O, and CH4 associated with soil chemical and microbiological attributes in the root region and out of root influence in areas submitted to different nitrogen doses and energy cane straw management. For this study, we will evaluate an experiment with energy cane located in Quatá, São Paulo State, Brazil, with the following treatments: i) control without nitrogen fertilization in the energy cane; ii) control without nitrogen fertilization in the sugarcane; iii) 60 kg N ha1 (energy cane); iv) 120 kg N ha1 (energy cane); v) 180 kg N ha1 (energy cane); vi) 120 kg N ha1 + 10 t ha1 of dry mass of straw (energy cane). This last treatment aims to represent straw maintenance on the soil surface, a practice that is not yet a reality in energy cane cultivation since all aerial biomass is harvested. We will determine soil CO2, N2O, and CH4 emission (use of static chambers), soil temperature, soil moisture, and soil chemical and microbiological attributes. Gases and soil samples will be collected in the rhizosphere (root region) and non-rhizosphere (out of root influence) regions. Data variability will be analyzed by means of descriptive statistics and analyses of variance and regression. The analysis of variance will be performed in a randomized block design and observations will be repeated over time. The behavior of variables as a function of the sampled site will be evaluated by means of the multivariate exploratory analyses of hierarchical clustering and principal components. The scientific challenge of this project will be to obtain indicators, mainly microbiological and environmental, as a function of the energy cane response to nitrogen doses and the presence of straw on the soil surface, as well as the adoption of more efficient agricultural practices for mitigating greenhouse gas emissions of anthropogenic origin, aiming at mitigating the contribution of agriculture to the global warming.