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Special PresentationsSoils: Sustainable management of the agricultural resourcebase F16Bourguignon, Claude L.A.M.S. F-21210 Marey-Sur-Tille, France |
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| Our world wide experiment of soils biology allow
us to advance that organic agriculture is a good solution for sustainable agriculture in
temperate countries but the best one for tropical countries. Our studies are based on
biological activity measurements of soils under natural vegetation. The reason of this
choice is due to the fact that natural systems are sustainable by definition since they
last so long time ( 30 millions of years for amazonian forest). In nordic countries,
organic matter contents of natural soils are very high due to a low biological turnover
(50% of the carbon is in the soil). In these cases, soil reserves of nutriments are high
and it is impossible to increase yields by organic farming. It is just possible to
maintain yields with lower costs and reduced use of fertilizers and pesticides. In
equatorial countries, organic matter contents of soils is very low, due to a very high
turnover of carbon (5% of the carbon is in the soil). In these soils, C.E.C is very low
and nutriments reserves too. In these conditions the chemical agriculture is unenforceable
without strong environmental disasters. The natural ecosystems are sustainable because
they have developped very efficient biological processes : Soil aeration by fauna, a zero
level of lixiviation despite high rainfallsby deep roots, biological assimilation process
for precipitated elements and biological protection again soil acidity and aluminium
toxicity. The knowledge and the application of these biological systems allows to developp
a highly productive sustainable agriculture as we show with our results on rice and
soybean production in Mato Grosso in Brazil. In south countries organic farming can't be
ignored. ?? |
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