Fertility & Fertilizer Placement
Soil Nutrition - Direct Seeding Advantage 2005
Carlos Crovetto - Concepcion, Chile
November 22, 2005
November 22, 2005
For 52 years I have managed the Chequen farm, located in the Concepcion province, 400 km south of Santiago, Chile's capital city. Their steep slopes together with high winter rainfall, extensive use of plowing and removal or burning of stubbles have left soils unprotected, and so exposed to high losses of soil material by water erosion.
Three million hectares have suffered losses up to thousand tons per hectare in 250 years of agriculture in Chile. This is why agriculture is hardly a profitable activity. Organic matter levels are below 3%, and the supply of nutrients to crops is very low, thus requiring large amounts of commercial fertilizers.
Dry soils with low organic matter contents are unable to retain rain and irrigation water, so that in dry summers grain crops or productive pastures are not possible.
In 1959 we stopped plowing the Chequen soils, and in 1978 we started maize and wheat crops under no tillage in areas with up to 35% slopes. Stubbles were seedbeds for these crops, and so erosion was prevented and soil physiological activities improved.
After 30 years of following this highly conservationist management system of nontillage, we have achieved an average soil growth of 1 mm per year or an increase of 0.2% organic mater every year.
Soil growth is due to outstanding uptakes of organic matter (6%) in humic form, as a consequence of surface stubbles decomposition.
Despite my neighbor’s evident pessimism about sowing without removing the soil, our yields increased up to 21,000 kg of corn and 10,200 kg of wheat per hectare, together with an efficient agronomic management of the soils. Large quantities of stubbles from crop rotations and winter pastures remain on the soil surface.
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