Resumo

ACEVEDO, David Cristóbal; HERNANDEZ ACOSTA, Elizabeth; MALDONADO TORRES, Ranferi  e  ALVAREZ SANCHEZ, María Edna. Spatial variability of carbon in soil after 10 years of incorporating and removing harvest residues. Terra Latinoam [online]. 2015, vol.33, n.3, pp.199-208. ISSN 2395-8030.

Accurately determining the behavior of soil organic carbon when agrochemicals are used and crop residues are removed (Conventional Management, CM) and when crop residues are incorporated into the soil and agrochemicals are not used (Organic Management, OM) has environmental and productive implications. To evaluate the effect of OM and CM on soil bulk density (SBD), soil organic carbon (SOC) and carbon sequestered by the soil (CSS), an experiment was conducted in plots planted with corn for 10 years. At the end of 10 years systematic sampling at a spacing of 5 m was performed: 152 samples in the organic plot and 72 in the conventional plot to determine SBD, SOC and CSS. With the data obtained, the behavior of each variable was analyzed using techniques of classical statistics and geostatistics. OM showed a higher percentage of SOC, a greater amount of CSS and a smaller SBD compared with CM, but there was no statistically significant effect (P > 0.05) of these practices. OM increased statistical variability of SOC and CSS, but did not affect the statistical variability of the SBD. Spatial variability of SOC and CSS expressed through semivariogram and isovalue maps coincided with variability expressed by the coefficients of variation, given by classical statistics. The spatial structure of SOC and CSS denoted by the experimental semivariogram was similar to the OM and CM. OM caused an increase in the spatial structure of SOC and CSS but had no effect on SBD.

Palavras-chave : bulk density; corn; soil sampling; semivariograms.

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