N2O production in soil cultivated sugarcane: influence of abundance and microbial composition

Abstract

The crop management of sugarcane can mediate the ability of soil to increase the organic carbon content and moisture, promoting and improving the conditions for the establishment of soil organisms. Thus, i) the microorganisms can plays a key role and may act as a source or sink N2O, and ii) the agricultural practices in the sugarcane crop can promote better understanding as the soil's ability to reduce emissions of N2O. However, is necessary more consistent information on the related on microbial processes and N2O emissions to the atmosphere in the sugarcane crop. This project proposes to seek some information in this regard, bringing together a multidisciplinary team of experiments that integrate knowledge in mineral nutrition, environmental biogeochemistry and soil microbiology. The experiment will be conducted in Iracemápolis-SP, Brazil, with different forms of N application, which will be subsequently examined the contribution of the microbial population and the potential of soils act as sink N2O. Additionally, micro-plots containing 15N will be installed for monitoring and 15N translocation of soil-plant. The treatment: 1) control (without nitrogen); 2) surface application (over the straw); 3) application below the layer of straw and over the soil; 4) application incorporated into the soil (10 cm deep). We sampling air collected in static chambers and measured by gas chromatography to N2O emissions, concurrently with the soil sampling at a depth of 0-10 cm will be sent for physical and chemical molecular analysis. Use the real-time PCR to quantify the 16S rRNA and nosZ genes and its transcripts, as well as, sequence of 16S rRNA and nosZ genes in Illumina platform to access the composition of the microbial community and functional group. The functional and phylogenetic information will be confirmed by proteomics in LC-MS/MS. The approach aims to recruit genes associated with the reduction of N2O in the soil and understand the co-occurrence of N2O reducing bacteria in the soil that can be indicator of N2O mitigation potential and measure the capacity reduction of N2O emissions due to the different forms of N Application in sugarcane crop. We use SparCC (Sparse Correlations for Compositional data) to elucidate networks of interaction among microbial diversity, functional genes and greenhouse gases living in the soil. This type of study has been incipient and is highly relevant, based on previous experiences observed in the FAPESP project (08/58075-8). The current proposal is directly related to CNPq Universal Project in Emerging Center entitled "Soil N2O emission and efficiency of use of N by the plant in different forms of N-fertilizer application in sugarcane" coordinated by Dr. Henrique J. Franco. (AU)