Can C-budget of natural capital be restored through conservation agriculture in a tropical and subtropical environment?
De Moraes Sa J.C., Lal R., Briedis C., De Oliveira Ferreira A., Tivet F., Inagaki T.M., Potma Gonçalves D.R., Canalli L.B., Bürkner dos Santos J., Romaniw J.. 2022. Environmental Pollution, 298 : 10 p..
Conservation agriculture through no-till based on cropping systems with high biomass-C input, is a strategy to restoring the carbon (C) lost from natural capital by conversion to agricultural land. We hypothesize that cropping systems based on quantity, diversity and frequency of biomass-C input above soil C dynamic equilibrium level can recover the natural capital. The objectives of this study were to: i) assess the C-budget of land use change for two contrasting climatic environments, ii) estimate the C turnover time of the natural capital through no-till cropping systems, and iii) determine the C pathway since soil under native vegetation to no-till cropping systems. In a subtropical and tropical environment, three types of land use were used: a) undisturbed soil under native vegetation as the reference of pristine level; b) degraded soil through continuous tillage; and c) soil under continuous no-till cropping system with high biomass-C input. At the subtropical environment, the soil under continuous tillage caused loss of 25.4 Mg C ha-1 in the 0–40 cm layer over 29 years. Of this, 17 Mg C ha-1 was transferred into the 40–100 cm layers, resulting in the net negative C balance for 0–100 cm layer of 8.4 Mg C ha-1 with an environmental cost of USD 1968 ha-1. The 0.59 Mg C ha-1 yr-1 sequestration rate by no-till cropping system promote the C turnover time (soil and vegetation) of 77 years. For tropical environment, the soil C losses reached 27.0 Mg C ha-1 in the 0–100 cm layer over 8 years, with the environmental cost of USD 6155 ha-1, and the natural capital turnover time through C sequestration rate of 2.15 Mg C ha-1 yr-1 was 49 years. The results indicated that the particulate organic C and mineral associate organic C fractions are the indicators of losses and restoration of C and leading C pathway to recover natural capital through no-till cropping systems.
Mots-clés : changement climatique; utilisation des terres; système de culture; agriculture de conservation; conservation des ressources; conservation de la nature; plante légumière; zone tropicale; zone subtropicale; atténuation des effets du changement climatique; changement dans l'usage des terres; émissions de gaz à effet de serre
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Agents Cirad, auteurs de cette publication :
- Tivet Florent — Persyst / UPR AIDA