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​​​​Title: Soil carbon stock under different pasture management systems in a subtropical highland environment

 

Abstract: The pastures provide economic support for ranchers and quality for raising cattle. I handle two pasture systems influencing the factors that control C dynamics in agriculture and therefore it is not your stock, not only. The aim of this study was to validate the carbon dynamics of our production systems only: Natural Pasture (NP), Improved Natural Pasture (IP), Perennial Pasture (PP) and Annual Pasture (AP) after 5 years of use in Cambisol at the EPAGRI experimental station, Lages (SC) Brazil. The four productive systems are considered to be arranged in block design each year, with four replications, since the spatial distribution of the two systems cannot be accidental. It is validated by particle size (pipette method), porosity (tension table method) and density (volumetric ring method) of organic carbon only (dry combustion) and layered carbon stock (0-5, 5-10, 10-20, 20-40, 40-60, 60-100 cm). Pastures are valued for their pasture production, C/N ratio of shoots, floristic composition and pasture root system for one year. Clay theory was undertaken as a variable in a statistical analysis of organic carbon and carbon stock. Forage systems significantly influenced the porosity and density of the soil, PN and PM were the least dense and most porous soils. The carbon contents of the systems varied only in the 0-5, 10-20 and 60-100 layers, and the variations in the superficial layers can be attributed to the management of the pasture systems. The soil carbon content of the evaluated systems is high and characteristic of the region's soils. Carbon stocks were similar between PN (270 Mg ha-1 ), PM (255 Mg ha-1 ), PP (274 Mg ha-1 ) and PA (256 Mg ha-1 ), which can be related the pasture management history. The DM production varied significantly from 6,615, 9,552, 9,771 and 13,044 kg ha yr-1 for PN (c), PM (b), PA (b) and PP (a), respectively. In general, forage productions were negatively affected by droughts in the last year of evaluation of the systems. PM and PN had greater floristic variety, density and root diameter when compared to PP and PA.

 

Keywords: Natural Pasture, Annual Pasture, Jiggs, Forage Production Density, Management. 

 

Author: Pedro Antonio Garzón Camacho

Leader: André Fischer Sbrissia

Dissertation (Masters in Animal Science)