No-till
From BioenergyWiki
Contents |
Definition
No-till practices (NT) refer to a type of conservation tillage, where seeds are planted directly in the soil without ploughing it beforehand. No-till practices are currently expanding, especially among soy producers in Argentina, Brazil and USA. Recent progresses tend to show that this practice can potentially be used for any crop, but not in all types of soil.
Benefits
No-till practices avoid soil disturbances such as compaction and fragmentation of layers, with various benefits such as: - Reduced soil erosion - Reduced soil compaction - Reduced disturbance to soil ecosystems (microbes, earthworms, insects) - Reduced water evaporation - Reduced oxidation of organic matter with consequently reduced GHG emissions (this aspect is controversial - see below) - Increased organic matter content over the long term
Controversies
- The most recent controversy concerns the potential benefits of no-till in terms of C sequestration and reduced GHG emissions. Whereas Soil Organic Carbon (SOC) shows higher content under no-till practices between 0 and 10cm of depth, this content is higher under Full Inversion Tillage (FIT) between 20 and 30 cm depth. See the special discussion page on No-till and GHG to participate in the discussion!
- In the first years after turning to no-till practices, yields are usually decreasing before increasing again, which prevents poor farmers, especially in developping countries, to take that risk, given the very weak financial safeguards in the absence of accessible credit systems.
- Since tillage helps removing weeds from the soil, no-till practices involve a quicker and more intense spreading of weeds and shrubs over the field. This leads some farmers to use greater amounts of pesticides such as glyphosate, whereas as Organic no-till farming requests more means and patience.
