Paradigms

Traditional soil cultivation systems in the tropics and subtropics, with intensive soil tillage, will end in soil degradation and loss of crop productivity. This will result in poverty, exodus of farmers from rural areas, resulting in an increase of city slums and marginal populations, and finally in social conflicts. If we are to offer the farm family a chance to survive on the farm and if sustainable agriculture is to be achieved, than the paradigms of soil use and management must be changed and new farming practices must be implemented. In this paper, the old and new paradigms are presented and the consequences of these two forms of soil management are analysed.

(Published in: ISTRO-INFO EXTRA, Vol. 4. 1999; available in ISTRO Web page at: http://www.soils.wisc.edu/istro)

Old paradigms	New paradigms
Soil tillage is necessary to produce a crop Burying of plant residues with tillage implements Bare soil for weeks and month Soil heating because of direct solar radiation Burning crop residues allowed Strong emphasis on soil chemical processes Chemical pest control, first option Green manure cover crops and crop rotations are options Soil erosion is accepted as an unavoidable process associated to farming on sloping land (Erosion is caused by excessive rains)	Tillage is not necessary for crop production Crop residues remain on the soil surface as mulch Permanent soil cover Reduced soil temperatures Burning mulch prohibited Emphasis on soil biological processes Biological pest control, first option Green manure cover crops and crop rotations compulsory Soil erosion is merely a symtom, that for that area and ecosystem unsuited methods of farming are being used (Erosion is caused by soil mismanagement)

Old paradigms

New paradigms

Soil tillage is necessary to produce a crop
Burying of plant residues with tillage implements
Bare soil for weeks and month
Soil heating because of direct solar radiation
Burning crop residues allowed
Strong emphasis on soil chemical processes
Chemical pest control, first option
Green manure cover crops and crop rotations are options
Soil erosion is accepted as an unavoidable process associated to farming on sloping land (Erosion is caused by excessive rains)

Tillage is not necessary for crop production
Crop residues remain on the soil surface as mulch
Permanent soil cover
Reduced soil temperatures
Burning mulch prohibited
Emphasis on soil biological processes
Biological pest control, first option
Green manure cover crops and crop rotations compulsory
Soil erosion is merely a symtom, that for that area and ecosystem unsuited methods of farming are being used (Erosion is caused by soil mismanagement)

Consequences of soil preparation and bare soil	Consequences of no-tillage and permanent soil cover
Wind- und watererosion are unavoidable Reduced water infiltration into the soil Less available soil moisture Unavoidable reduction in the soil organic matter content; thus reduction of soil quality Soil carbon is lost as carbon dioxide into the atmosphere contributing to global warming Soil degradation (chemical, physical and biological) Reduction of crop productivity Higher use of fertilisers and higher costs of production Survival of the farm family on the farm threatened (lower yields, production without profitability, insufficient monetary income) Poverty, rural exodus, increase of slums and marginal populations as well as social conflicts	Wind- und watererosion near zero Increased water infiltration into the soil More available soil moisture Maintenance or increase in the soil organic matter content (enhancement of soil quality) Carbon is sequestered in the soil enhancing its quality, reduciing the threat of global warming Soil improvement (chemical, physical and biological) Crop productivity increased Reduced use of fertilisers and lower production costs Survival of the farm family on the farm isured through a good profitability and high and sustainable crop production Basic needs are satisfied, living standard and quality of life of the farm family are increased

Consequences of soil preparation and bare soil

Consequences of no-tillage and permanent soil cover

Wind- und watererosion are unavoidable
Reduced water infiltration into the soil
Less available soil moisture
Unavoidable reduction in the soil organic matter content; thus reduction of soil quality
Soil carbon is lost as carbon dioxide into the atmosphere contributing to global warming
Soil degradation (chemical, physical and biological)
Reduction of crop productivity
Higher use of fertilisers and higher costs of production
Survival of the farm family on the farm threatened (lower yields, production without profitability, insufficient monetary income)
Poverty, rural exodus, increase of slums and marginal populations as well as social conflicts

Wind- und watererosion near zero
Increased water infiltration into the soil
More available soil moisture
Maintenance or increase in the soil organic matter content (enhancement of soil quality)
Carbon is sequestered in the soil enhancing its quality, reduciing the threat of global warming
Soil improvement (chemical, physical and biological)
Crop productivity increased
Reduced use of fertilisers and lower production costs
Survival of the farm family on the farm isured through a good profitability and high and sustainable crop production
Basic needs are satisfied, living standard and quality of life of the farm family are increased

Off farm effects of soil erosion	Off farm effects of new production system
Sedimentation of rivers, reservoirs, lakes and micro catchments Reduced water quality Problems in hydroelectric power plants Sedimentation of roads Higher costs for the goverment and for society due to off farm effects of soil erosion	Reduction of sedimentation of rivers, reservoirs, lakes and micro catchments Enhanced water quality Less problems for hydroelectric power plants Less sedimentation of roads Reduction of costs for the goverment and for society due to off farm effects of soil erosion

Result	Result
Sustainable land use is not possible (ecologically, socially & economically). Soil resource explotation.	Sustainable land use ensured (ecologically, socially & economically). Rational, site- oriented use of the soil.