Papers

Soil tillage and cover crop on soil CO2 emissions from sugarcane fields

Author: Farhate, C. V. V. ; SOUZA, Z. M. ; LA SCALA JÚNIOR, N. ; SOUSA, A. C. M. ; Santos, A. P. G. ; Carvalho, J. L. N.

Keywords: conventional tillage, greenhouse gases, minimum tillage, soil organic matter, soil respiration, sunn hemp

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Summary

Soil  tillage  is  an  agricultural  practice  that  directly  affects  the  global  carbon  cycle.  Our study sought to assess the implications of adopting sunn hemp cover crops with different tillage practices on CO2 emissions for two soil types (clayey and sandy soil) cultivated  with  sugarcane  in  Brazil.  The  experimental  design  was  a  split-  plot  with  randomized blocks, with the main plots being with cover crop or fallow and sub- plots being  under  conventional  or  minimum  tillage.  Our  results  indicate  that  during  the  first 50 days after soil tillage, the variation in soil CO2 emissions was stimulated by cover crop and soil tillage, while after that, it became dominated by the root respira-tion of sugarcane plants. We also found that over the first 97 days after the tillage, the clayey soil showed differences between minimum tillage with cover crop and fallow. Conversely,  for  sandy  soil  over  the  first  50  days  following,  there  were  differences  between the tillage systems under cover cropping. Emissions from sugarcane rows were found to be greater than those from inter- row positions. We concluded that soils under different textural classes had distinct patterns in terms of soil CO2 emissions. The correct quantification of CO2 emissions during the sugarcane renovation period should prioritize having a short assessment period (~50 days after soil tillage) as well as including measurements at row and inter- row positions