Dissertations and Theses

Summary

Soil preparation has been pointed out as one of the practices that cause additional loss of carbon from the soil to the atmosphere in the form of CO2, the main greenhouse gas extended. In this work, some aspects of the CO2 emission of the soil of agricultural areas in the region of Jaboticabal, SP, Brazil, are studied. The experiments were carried out in two areas where the effect of soil preparation with disc plow was studied, followed by leveling grid (conventional), combined trawl scarifier with dewatering roller (reduced) and rotating hoe on soil CO2 emissions. In the experiment conducted with the rotating hoe, its application on a plot with and without sugarcane straw was considered, and the effect of the presence or not of straw on the surface of the soil on CO2 emissions was also investigated. Already in the experiment that contemplated the conventional preparation and reduced the total emissions indicated that the system of preparation disk plow followed by high grader was the most impacting, resulting in a loss of soil carbon near 71 g m -2 (260 g CO2 m -2) in 2 weeks. Regarding the influence of the straw on the emissions after preparation, these were significant increasing the emission in 36% above that of the portion after preparation without straw. The results presented invariably a decrease of the CO2 emission of the soil over time after preparation, which was best modeled in one of the experiments from an exponential function decreasing in time only, while in the other experiment by a combined, exponential function decreasing in time and linear dependence with soil temperature and humidity, was the one that best adjusted the temporal variations of the emission after preparation.