Soil CO2 emission after conventional and reduced tillage in dry and rainy periods

Abstract

Agricultural practices affect soil CO2 emission, this being nowadays a subject of great interest. The objective of this work was to study the effect of the conventional (disk plow followed by offset disk harrow) and reduced tillage (chisel plow) on soil CO2 emission during dry and rainy periods. The experiment was set in a red latosol in Jaboticabal, state of São Paulo, Brazil, where the climate is tropical with rainy summer and dry winter. The soil CO2 emission and soil temperature were registered by a portable chamber and temperature sensor of the LI-6400 system. CO2 emissions differed significantly after soil tillage only in the dry period of the year (winter). Total soil CO2 emission was dependent on the tillage system as well as the chisel plow knife spacing after reduced tillage, these differences being close to 40 g CO2 m-2 during the winter period. Modifications in soil CO2 emission, during the winter time, seemed more related to the occurrence of rains whereas during summer time those modifications seemed to be related to soil temperature.Additional keywords: soil management; gaseous exchange; carbon dioxide.