Impact of land use on greenhouse gas and soil carbon emissions in eastern Amazonia: phase 1

• Grant number: 19/25234-0
• Support type: Regular Research Grants
• Duration: October 01, 2021 - September 30, 2023
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Pastures and Forage Crops
• Cooperation agreement: CONFAP - National Council of State Research Support Foundations
• Principal researcher: Ricardo Andrade Reis
• Grantee: Ricardo Andrade Reis
• Home Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil
• Assoc. researchers: Abmael da Silva Cardoso ; Ana Cláudia Ruggieri
• Associated scholarship(s): 22/10814-4 - Effect of lan use system on total C and organic matter fractions, BP.TT; 21/13501-4 - Effect of land use system on total C and organic matter fractions, BP.TT

Abstract

Farming is one of the main greenhouse gas emitting agents, such as carbon (CO2) and nitrous oxide (N2O). Much of Brazil's contribution to CO2 emissions is due to the relatively recent change in land use and driven mainly by deforestation for land tenure through the burning and incorporation of soil material without nutrient replenishment into this system. Landowners use pasture as the cheapest way to "use" land for economic benefit. Already N2O is a gas emitted through the excretion of feces and urine of animals, in addition to the emission provided by nitrogen fertilization. Thus, agriculture ends up being considered a villain, due to the high potential of gas emissions, but management strategies provide a reduction in the emission of these gases, since the soil carbon stock in pastoral systems is similar to that of areas of native forest. The objective of this study is to evaluate the carbon stock and N2O flux of soils subjected to land use change in different climate classifications of the Amazon biome. After consultation with local producers, three different systems with four replications in each climate type (Af, Am and Aw) will be selected, and systems in the same climate should have the same soil type (Class and Texture). All should have in common adjacent areas with intensive pasture, extensive pasture, agriculture and native vegetation (VN). Field collections will take place from April to December 2020. For N2O flow assessment, a home-based climate production system will be chosen. Chronossequences will be validated through pasture productivity, forage growth, existing litter, tillers population density and light fraction of soil organic matter. A ~ 1 m trench will be opened for soil collection and the intervals taken for sampling will be from 0 to 5, 5 to 10, 10 to 20, 20 to 30, 30 to 40, 40 to 60, 60 to 80 and 80, at 100 cm. From soil samples will be evaluated soil texture, light fraction of MOS, total C, total N and abundance of 13C. The N2O flow will be evaluated by static chamber incubation, will be performed three incubations, the first testing the agricultural systems of each climate following a 4 x 3 factorial IHD scheme, in the second incubation the soils will be subjected to nitrogen fertilization (0, 90, 180 and 270 kg ha-1) following a 4 x 3 x 4 factorial IHD scheme and in the third incubation the soils will be subjected to temperature elevation (25, 30, 35 and 40 °C) following a IHD scheme with a 4 x 3 x 4 factorial model, all with five repetitions, and the sampling being performed between 9 and 10 hours. (AU)