CO2 Emission from Soil Affected By Crop Rotation Systems Under No-till.

The objective of this study was to assess the CO2 soil emissions into the atmosphere throughout a soybean cultivation as affected by different crop rotations under no-till. This experiment has been conducted in Botucatu, SP, Brazil, under no-till and with the same crop rotations since 2003. The experiment was carried out a split plot design in Typic Rhodudalf. The plots constituted by winter crops triticale (X Triticosecale Wittmack) and sunflower. The subplots and managements spring involving pearl millet, sorghum and sunn hemp, and chiseling/fallow (2003; 2009; 2013). In the summer was cropped with soybean. The CO2 emission from soil, as well as soil moisture and temperature, was measured at 1, 2, 3, 8, 15, 30, 60, 90 and 120 days after soybean sowing (2013/14), using an Automated Flux CO2 Soil System, LI-8100A. Generally speaking, CO2 emissions from soil were lower in the sunn hemp and chiseling/fallow land subplots and in the sunflower plots. The largest CO2 emission peaks were observed at 60 days after soybean sowing. It was found a strong positive correlation between CO2 soil emission and soil temperature and moisture, so those high CO2 emission values occurred much probably due to high temperature and moisture of the soil.