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Tropical soils degraded by slash-and-burn cultivation can be recultivated when amended with ashes and compost.

ABSTRACT: In many tropical regions, slash-and-burn agriculture is considered as a driver of deforestation; the forest is converted into agricultural land by cutting and burning the trees. However, the fields are abandoned after few years because of yield decrease and weed invasion. Consequently, new surfaces are regularly cleared from the primary forest. We propose a reclamation strategy for abandoned fields allowing and sustaining re-cultivation. In the dry region of south-western Madagascar, we tested, according to a split-plot design, an alternative selective slash-and-burn cultivation technique coupled with compost amendment on 30-year-old abandoned fields. Corn plants (Zea mays L.) were grown on four different types of soil amendments: no amendment (control), compost, ashes (as in traditional slash-and-burn cultivation), and compost + ashes additions. Furthermore, two tree cover treatments were applied: 0% tree cover (as in traditional slash-and-burn cultivation) and 50% tree cover (selective slash-and-burn). Both corn growth and soil fertility parameters were monitored during the growing season 2015 up to final harvest. The amendment compost + ashes strongly increased corn yield, which was multiplied by 4-5 in comparison with ashes or compost alone, reaching 1.5 t/ha compared to 0.25 and 0.35 t/ha for ashes and compost, respectively. On control plots, yield was negligible as expected on these degraded soils. Structural equation modeling evidenced that compost and ashes were complementary fertilizing pathways promoting soil fertility through positive effects on soil moisture, pH, organic matter, and microbial activity. Concerning the tree cover treatment, yield was reduced on shaded plots (50% tree cover) compared to sunny plots (0% tree cover) for all soil amendments, except ashes. To conclude, our results provide empirical evidence on the potential of recultivating tropical degraded soils with compost and ashes. This would help mitigating deforestation of the primary forest by increasing lifespan of agricultural lands.

SUBMITTER: Gay-des-Combes JM

PROVIDER: S-EPMC5528233 | biostudies-literature | 2017 Jul

REPOSITORIES: biostudies-literature

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Tropical soils degraded by slash-and-burn cultivation can be recultivated when amended with ashes and compost.

Gay-des-Combes Justine Marie JM Sanz Carrillo Clara C Robroek Bjorn Jozef Maria BJM Jassey Vincent Eric Jules VEJ Mills Robert Thomas Edmund RTE Arif Muhammad Saleem MS Falquet Leia L Frossard Emmanuel E Buttler Alexandre A

Ecology and evolution 20170612 14

In many tropical regions, slash-and-burn agriculture is considered as a driver of deforestation; the forest is converted into agricultural land by cutting and burning the trees. However, the fields are abandoned after few years because of yield decrease and weed invasion. Consequently, new surfaces are regularly cleared from the primary forest. We propose a reclamation strategy for abandoned fields allowing and sustaining re-cultivation. In the dry region of south-western Madagascar, we tested, ...[more]

PMID: 28770075

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Tropical soils degraded by slash-and-burn cultivation can be recultivated when amended with ashes and compost.

Publications

Tropical soils degraded by slash-and-burn cultivation can be recultivated when amended with ashes and compost.

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