Calcium and magnesium silicate and lime on the carbon balance in long-term no-tillage system

Abstract

The increase in temperature caused by the high concentration of greenhouse gases (GHG) has a negative impact on food production by agriculture. Agriculture is one of the sectors that most contributes to the growth of the national gross domestic product, accounting for 21% of the total wealth produced. Global warming has been intensified by anthropogenic GHG emissions, among which CO2 is a major contributor. Conservationist agricultural production systems, such as no tillage systems (NT), are alternatives to control soil carbon (C) loss and minimize GHG emissions. Lime soil correction is used to raise the pH and mitigate the effects of aluminum (Al) and manganese (Mn) toxicity in the soil. However, the dissolution of CaCO3 generates CO2, unlike calcium and magnesium silicate (Ca:MgSiO3), which does not emit CO2 during dissolution and has been proven effective in correcting soil acidity. The increase in carbon input and sequestration in agricultural production systems occurs through the photosynthetic processes of plants that remove atmospheric CO2 to be stored in the soil. Thus, the objective of this project is to evaluate the carbon balance through the application of different acidity correctives (limestone and calcium and magnesium silicate) and control (without correction) in a long-term experiment with soybean and maize in succession, intercropped with Urochloa ruziziensis. The carbon inputs from the aerial parts and roots of soybean, maize, and brachiaria plants, as well as C-CO2 fluxes, will be evaluated. By the end of this project, it is expected to demonstrate that corrected systems are more advantageous from agronomic and environmental perspectives than uncorrected systems, and to prove that calcium and magnesium silicate is more advantageous than limestone in environmental aspects.