Simplified cropping techniques (SCT)
TCS are methods of work limiting soil tillage. Mechanically worked soils quickly become very poor in organic matter and the topsoil layer decreases. TCS (Simplified Cropping Techniques) were initially invented to address this. Along with direct seeding, they constitute no-tillage cropping techniques. They include all techniques of work without soil inversion such as strip-till, shallow tillage, or pseudo-tillage. TCS are often a step before conversion to conservation agriculture and characterize the third agricultural revolution.
The origin of their development in European countries comes from the drop in cereal prices in the 1990s followed by the increase in fuel prices. These two factors led farmers to reconsider their production costs. This led some growers to eliminate a major labor and fuel cost: plowing. The adoption of these new techniques resulted in agronomic benefits. These agricultural techniques allow the valorization of agroecosystem diversity by offering solutions adapted to local situations while reducing the energy input into the system. Cover crops were then integrated into these cropping techniques. The biological activity of the soil is enhanced. This approach, taken to its maximum, conservation agriculture, is supported by the FAO.
What are their advantages?
- They limit soil erosion because plant debris, stubble, and straw are left on the surface of the plot and form a physical protection against rain.
- They promote the development of microfauna, notably earthworms, which improve soil structure and loosen the earth in place of the farmer. These techniques avoid exporting mineral nutrients contained in the straw and contribute to system sustainability.
- They favor water infiltration into the soil and the gradual replenishment of groundwater by preventing erosion from runoff. They induce greater resistance to drought.
- They help fight mycotoxins by recreating a rich microbial life in the soil. The soil becomes a living ecosystem rich in organic matter.
- They contribute to reducing nitrogen fertilizer inputs in the medium term.
- They enlarge the "weather windows": the farmer, no longer occupied with plowing, has more security to carry out work under optimal conditions.
- They can reduce energy consumption and farmers' working time by up to 40%. The CO2 stored in the soil significantly contributes to reducing greenhouse gases.
- They require less agricultural equipment, thus less capital and energy.
The goal is to minimize the input of inputs so as not to disturb soil life, which also limits pollution and energy consumption. Finally, biodiversity also benefits from these measures.
Although the transition from a conventional system to a TCS system can cause an invasion of weeds and the possible need to use high doses of herbicides, after a few years balances form between beneficial organisms ("useful" organisms) and pests, and pesticide and mineral fertilizer use decreases sharply. Yields in steady-state years can be equivalent to a conventional system.
What are their disadvantages?
- They favor plant pests and diseases if the mulch is made at a wrong time or buried superficially.
- They make it more difficult to control weeds and undesirable organisms such as slugs, at least at the beginning of their implementation. This is why a good crop rotation and intercrops are important. Learning the techniques and returning to proper system functioning sometimes takes a few years and can be somewhat tricky; otherwise, phytosanitary product costs can become prohibitive or yields may suffer.
- There is also a concentration of phytotoxic substances on the surface for crops, notably sulfonylureas for rapeseed and napropamide for vegetables. The problem is such that crops do not germinate. Plowing sends phytotoxic substances to the bottom of the furrow and thus does not disturb the future crop.
The development of cover cropping is linked to the use of glyphosate, a low-cost total herbicide that allows destruction of the cover crop after sowing. The withdrawal of this active ingredient as currently envisaged would be detrimental to this establishment technique because there is no satisfactory replacement solution. Faca rollers, or bar rollers, developed in Brazil are not suitable for cover destruction under our conditions.
