Conservation tillage is a method of soil cultivation that leaves the previous year's crop residue on fields before and after planting the next crop. It is mainly done to reduce soil erosion and runoff. Conservation tillage methods include no-till, strip-till and mulch-till. Each method requires different types of specialized or modified equipment and adaptations in management. No-till and strip-till involve planting crops directly into residue that either hasn't been tilled at all (no-till) or has been tilled only in narrow strips with the rest of the field left untilled (strip-till). Mulch-till is any other reduced tillage system that leaves a part of the soil surface covered with crop residue.
Measured soil water content hydrographs comparing conventional with conservation practices for a soil in Saxony (soil type UT4, soil depth 20cm)
The effects in terms of flood protection are:
- Improved soil structure with plant / mulch residues due to higher availability of stable aggregates
- Increasing the infiltration by increased vertical macro or coarse pores
- Slowing down and reduction of surface runoff due to the mulch layer
- Better usage of soil water storage capacity with an improved hydraulic conductivity in deeper soil layers due to the changes in pore size distribution and stability.
Improve the water permeability following Slade compaction as a consequence of increased earthworm activity.
Effects in terms of nature conservation:
- Reduction of water erosion (max. 95%)
- Protection of surface water by reducing fertilizers and pollutants wash out
- Promote soil fauna proliferation and increase in microbial activity
Advantages and disadvantages of conservation tillage
Increased proportion of plant-available water (higher infiltration, less runoff)
Reduction of CO2 emissions per unit area compared to conventional arable farming
- Improved soil fertility / profitability
- Improve soil structure
Higher demands for management and crop production (crop rotation, residue management, crop variety selection, etc.)
Intensive field inventory control compared to conventional methods