Msc. Leiliane Zeferino1, Prof. Carlos Eduardo Cerri2, Prof. Teogenes Oliveira1
1Universidade Federal de Viçosa, Vicosa, Brazil, 2Escola Superior de Agricultura Luiz de Queiroz, Piracicaba, Brazil
The increase in global food demand together with climate change require sustainable agriculture that adopts practices to maximise productivity and minimise damage to the environment by CO2 emissions, favouring stocks of soil organic matter (SOM). Over the last 30 years, the transition environments of the Amazon-Cerrado Forest in the eastern Brazilian Amazon, has seen the removal of approximately 32.3 thousand ha of native vegetation, while areas of pasture have increased by 30 thousand ha. The aim of this study was to evaluate the impact of converting forests to pasture on C and N stocks in transition environments, as well as the effects of different management practices on the sequestration of atmospheric CO2. The changes were simulated for the 0-20 cm layer using the Century model v 4.0, with adjustments to determine the parameters of biomass production. Simulated stocks of steady state SOM C and N under native vegetation were used to adjust the deforestation model and the subsequent establishment of pasture. Eight future production scenarios were simulated for 2050 and compared to the current situation of the lack of management practices (M), namely: M1: pasture managed without periodic renewal; M2: pasture with chemical control of spontaneous species; M3: pasture with top dressing only; M4: pasture with top dressing and maintenance fertiliser; M5: pasture with top dressing and maintenance fertiliser together with the chemical control of spontaneous species; M6: silvopastoral system with 30% tree cover; M7: pasture managed through the use of fire; and M8: grazing under intensive management. Except for M4, M5 and M8, all the other scenarios promoted an increase in the stocks of C and N in relation to the current situation of pasture management. The silvopastoral systems, irrespective of soil type, showed greater potential for maximising the sequestration of atmospheric C.
Teogenes Senna de Oliveira holds a PhD (1996) in Plant Science (Plant Production) at Federal University of Viçosa. I am currently a Full Professor at the Federal University of Viçosa. I am developing academic and scientific activities that seek to evaluate the consequences of intensive soil use, together with the design and evaluation of more environmentally balanced agricultural systems, made possible through the understanding and application of concepts for reinforcing ecological processes and relationships with both high and low external-input cultivation systems: irrigated systems, mixed cropping (agroforestry) systems, organic, and minimum tillage systems, all with a view to strengthening ecological processes and relationships.