Utilização de fertilizante de eficiência aumentada em pastagem sob sistema de integração lavoura-pecuária em solo arenoso

Abstract

The growing demand for food production poses significant challenges to sustainable agricultural practices. Integrated crop-livestock (ICL) systems have emerged as diversified approaches to address these challenges. Pasture management in these systems plays a crucial role in optimizing forage production and efficiently utilizing resources to enhance overall productivity. This study investigates the use of technologically advanced nitrogen fertilizers, specifically NBPT + Duromide-coated urea and formaldehyde-coated urea, aiming to reduce nitrogen (N) losses, particularly through ammonia volatilization (NH3-N), and consequently mitigate carbon dioxide emissions in sandy soil within the ICL system. Evaluations spanned three agricultural years (2020-21, 2021-22, and 2022-23), utilizing Urochloa Brizhanta cv. marandu pasture and NS-6828 and NS-6700 soybeans. The soil, characterized as dystrofic Ultisol, exhibited a sandy texture. Employing a randomized complete block design with four replications in a 3x4 factorial scheme, treatments included three N sources: conventional urea (UrConv), slowrelease formaldehyde-coated urea (UrForm), and urea with urease inhibitor and Duromide technology (UrDuromide), each with four doses (0, 100, 200, and 400 kg ha-1 of N). Analysis of carbon dioxide (CO2) emissions and total organic carbon (TOC) involved testing for dose × source interaction using Statistical Analysis System software. Nonlinear regression, employing a logistic model, was applied to NH3-N volatilization data. Nitrogen losses varied with dose and fertilizer, reaching up to 33% with UrConv. UrDuromide exhibited declining efficiency over the evaluation period, resulting in losses reduced by 52% in the first year, 46% in the second, and only 5% in the third. UrFormaldehyde demonstrated less variability, with reductions in NH3-N losses ranging from 57% to 45%. Trends in TOC and CO2 emissions mirrored each other, with UrConv contributing to the highest CO2 emissions and TOC accumulation. UrDuromide showed a promising up to 6% reduction compared to UrConv in greenhouse gas emissions and, consequently, lower TOC accumulation. In conclusion, the use of technology to enhance nitrogen fertilizer efficiency presents a promising avenue for reducing greenhouse gas emissions, providing a viable alternative in comparison to conventional urea sources.