Soil organic matter dynamics and land-use change on Oxisols in the Cerrado, Brazil

• Published in: Geoderma Regional Vol. 14; p. e00178
• Main Authors: Gmach, Maria-Regina, Dias, Bruno O., Silva, Carlos A., Nóbrega, Júlio C.A., Lustosa-Filho, José F., Siqueira-Neto, Marcos
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2018
• Subjects: afforestation; Brazil; carbon; carbon sinks; cerrado; climatic factors; Eucalyptus afforestation; Eucalyptus urophylla; feedstocks; humic acids; indigenous species; land use change; MATOPIBA; no-tillage; No-tillage system; Oxisols; Pasture; pastures; Soil carbon; Urochloa brizantha; Xanthic Ferralsols; Brazil; MATOPIBA; No-tillage system; Eucalyptus afforestation; Pasture; Xanthic Ferralsols; Soil carbon
• ISSN: 2352-0094; 2352-0094
• DOI: 10.1016/j.geodrs.2018.e00178

Land-use change (LUC) from native vegetation to feedstock production is the main responsible for the losses of carbon (C) from soil organic matter (SOM) to atmosphere. We evaluated different land-uses common in the Cerrado with potential to restore SOM levels. We sampled soil (0.0–0.1; 0.1–0.2; 0.2–0.3; 0.3–0.4 m) from sites located in the municipality of Uruçuí (Piauí State, Northeast region of Brazil). Land-uses evaluated were: i) native vegetation (NV); ii) no-tillage over six years (NT6); iii) no-tillage over nine years (NT9); iv) Urochloa brizantha pasture over two years (PA2); v) U. brizantha pasture over six years (PA6); vi) Eucalyptus urophylla afforestation over six years (EU6); and vii) E. urophylla afforestation over twelve years (EU12). We determined soil C stocks, chemical (fulvic and humic acids) and physical (particulate and organic-mineral complexes) SOM fractions. Pasture was land-use that presented better results in terms to maintain C pools (recalcitrant and labile), consequently could restore soil C stocks. The no-tillage, due to the high difference between the results for the adoption times, was difficult to have an accurate interpretation if is effectively increasing the C stocks. On the other hand, Eucalyptus afforestation does not seem to be an efficient land-use when it comes to the restoration of SOM levels, at least under the current management practices as well as the soil and climatic conditions in the Cerrado. •LUC reduced one-third of original soil C stock in MATOPIBA Cerrado.•No evaluated land-uses had the capacity to restore original SOM levels.•Pasture presented potential to maintain C pools, thereby increasing SOM levels.•Eucalyptus afforestation was not efficient in recovering SOM levels in MATOPIBA Cerrado.