Short-term spatiotemporal variation of soil CO2emission, temperature, moisture and aeration in sugarcane field reform areas under the influence of precipitation events

Soil CO(2)emission (FCO2) in agricultural areas results from the interaction of different factors such as climate and soil conditions. Our objective was to investigate the spatiotemporal variation of FCO2, temperature (T-soil), moisture (M-soil) and air-filled pore space (AFPS), as well as their interactions, during the sugarcane field reform. The study was conducted on a 90 x 90 m sampling grid with 100 points at 10 m spacings. Ten assessments of FCO2, T(soil)and M(soil)were carried out at each point over a 28-day period. The greatest mean values of FCO2(0.74 g m(-2) hr(-1)) and M-soil(31.7%) were obtained on Julian day 276, 2013, being associated with precipitation events at the study site. Also, the smallest values of AFPS (19.17%) and T-soil(20.90 degrees C) were observed on the same day. The spatial variability of FCO2, T-soil, M(soil)and AFPS was best described by an adjusted spherical model, although an exponential model better fitted some results. The spatial pattern of all soil attributes showed little temporal persistency, indicating a high complexity for FCO(2)during precipitation. Correlation maps assisted in identifying regions where M(soil)and AFPS better controlled the emission process and where T(soil)was important. A major challenge for world agriculture is to increase the efficiency of conventional soil management practices. We highlight the importance of the spatial pattern of soil properties that directly influence the CO(2)emission dynamics. Future mitigation actions should involve less intense tillage and ensure homogeneous applications of soil inputs, thereby reducing production costs and the contribution of these activities to CO(2)emissions during the sugarcane field reform.