Managing Cultivation for Flood Risk Management
Content Table
Mitigation Strategy
The Mitigation Strategy of Conservating Cultivation refers to flood prevention and environmental protection also.
Flood protection can be achieved by:
- Reducing soil silting because of improved land cover with a rest of plants and mulch as well as higher percentage of stable soil aggregates,
- Increasing infiltration through increased vertical macro- and coarse pores (especially worm tubes),
- Slowing down the surface run off due to the mulch edition,
- Better utilization of water storage capacity of the soils and increased hydraulic conductivity in deeper soil layers by the change of pore size allocation, establishment of a stable pore system while increasing the proportion of biogenic medium and macro pores.
Environmental protection by:
- Reducing water erosion (up to 95 % max.),
- Protection of surface water by reducing eroded sediment nutrient and contaminant discharge,
- Support the soil fauna and increased microbial activity.
Time to take effect
The transition (change) phase combined with reduced yields lasts 2-5 years.
Pros & Contras
Pros
- Reduction of site related CO2 emissions compared to conventional arable farming,
- Increased proportion of plant-available water (increased infiltration, reduced evapotranspiration, less surface run-off),
- Furtherance the tilth, soil fertility and harvest,
- Improving the capacity and trafficability of the soil (more stable structure, more stable system of pores, even in moist soil condition).
Cons
- As a result of unfavorable conditions (long lasting chilly and damp weather, with the consequence of higher soil water contents and low soil temperature), slower plant growth is possible due to a delayed release of Nitrate,
- Increased demand of management (crop rotation, straw management, variety selection etc.) and more intensive field inventory control,
- Introduction of conservation tillage in organic farming is more difficult, since it is the safest weed control by use of plow,
- Danger of the spread of diseases and pests and the incidence of specific weeds and grass weeds etc., especially in unadapted rotation.
Cost Data Summary
- Learning costs,
- Investment in new machinery,
- Cost of the change phase (with the possibility of harvest reduction),
- Cost for changing the crop rotation with economically less attractive crops.
Reducing costs through:
- Savings in fuel and/ or working operations,
- Potential cost reduction of 40-60 Euro compared to conventional tillage, if achieve high management standards,
- Increase of the competitiveness of agriculture combined with increasing the flood protection potential by optimal implementation of this measure,
- Cost savings due to heavy erosion reduction of at least 4.8 Euro per tonne,
- Reduction of off-site damage, for example cleaning costs for dirty streets.
A cost benefit analysis has to be done separately for each individual project. A possible procedure and the coast range for alternative solutions you will find here (link).
References
SIEKER, F. (2007): Maßnahmensteckbrief "Umwandlung von Acker in extensives Grünland", In: INSTITUT FÜR WASSERWIRTSCHAFT, HYDROLOGIE UND LANDWIRTSCHAFTLICHEN WASSERBAU (2007): Abschlussbericht zum Forschungsprojekt "Vorbeugender Hochwasserschutz durch Wasserrückhalt in der Fläche unter besonderer Berücksichtigung naturschutzfachlicher Aspekte - am Beispiel des Flusseinzugsgebietes der Mulde."
