What is Directa (No-till system)?
Directa or No-till system is the most evolved system for planting without any tillage. This system eliminates any kind of tillage, while a permanent residue cover stays over the soil. The most fertile layer of the soil is in its first centimeters and if this layer disappears, nature would take thousands of years to create it again.
Retaining this cover layer, we protect and improve soil fertility and eliminate soil erosion. Directa (No-till system) is also an agricultural technique which increases the amount of water which infiltrates into the soil.
Conserving the organic matter
Using the conventional technologies for planting, we suffer losses of organic matter of the soil (humus) due to the constant laboring of it. Organic matter is essential for both chemical and physical properties of the soil, providing nutrients and helping to keep stability in the soil structure.
Losing organic matter means losing potential fertility which leads to money spent on fertilizers for the soil. Instead of making investment in fertilizers in order to maintain soils potential, you can redirect the investment to other areas of interest.
More water for crops
The rotation of crops with different root systems promotes the regeneration of pores, fauna and soil biological activity. This leads to a better soil structure with more efficient use of water, by reducing run off and evaporation losses.
Up to 100 mm of useful water are gained every year in Argentina with direct planting, compared to conventional tillage, and, according to the efficiency in use of the water from each crop, it represent an increase of 1.700 kg of maize per hectare and 800 kg of wheat per hectare in one year.
No-till planter – a strong pillar of this technology
In order to be efficient, the system must go together with a complex and specially designed agricultural machine. It is very important to have planting machine which can properly penetrate through the residue, into the soil and prepare a good seedbed from only one passing over.
Switching to no-till reduces the maximum amount of power needed for tractors, which means the farmer can use a smaller tractor, compared to conventional plating where it is required a more powerful one (especially due to plowing).
It is more important in no-till than in conventional till systems. Most agronomic benefits of no-till result from the presence of soil cover at the soil surface which should be around 50% from the field. Some crops leave very little crop residue behind, leading to minimal residue cover (corn silage, soybeans), but other crops (corn or winter cereals), leave large amounts of residue behind, some of them lasting for two years (corn).
Therefore, sufficient cover can be obtained only by rotating high-residue crops with low-residue crops, some residue from the high-residue-producing crop caring over into the low-residue-producing crop.
Certain weeds are avoided by using crop rotation. Different herbicide programs are used in order to avoid the development of herbicide resistance in weeds. Some diseases and insects survive on residues of a specific crop, but if the crops are rotated, the threat of the harmful insects or disease is eliminated.
Chemical treatment in Directa (No-til system)
Without any doubt an important aspect of Directa (No-till system) is chemical treatment in the cropping system. There is an increased use of herbicides because weeds must be control during their vegetative period and, as tilling machines are no longer used, herbicides should be used to control them.
During all vegetative stages, the herbicides used to control the weeds are completely the same as in the case of conventional system. When talking about chemical treatments, the main role is played by the sprayer which must have a working width as wide as possible, in order to reduce total amount of crossings and laps on the crop field.
What most of the people doesn’t know is that glyphosate is one of the least polluting herbicides of all. When contacting with soil particles it becomes inactive and leaves no traces on the ground. Thousands of studies are made every year in order to find out if there is a pollution from it, but there are no conclusive scientific proves for that.
No-till is more profitable than tillage systems, even if yields are the same, because the costs are reduced. First of all, tillage equipment and its maintenance are eliminated, thus field operations take less time. Secondly, fuel costs are reduced, as well as tractor horse power requirements. Thirdly, labor costs are reduced because the farmer needs only a planter, a sprayer and a combine for field crop production.
There are also added costs to no-till, such as herbicides application. However, the additional costs are much smaller compared to the savings. The farmers also experience greater profits because they can manage more hectares than the farmers who choose tillage systems.
No-till system leaves more crop residue on the soil surface, which improves soil quality and results in better infiltration of water, reducing irrigation costs as well.
When to start using Directa (No-till system)?
All little details that we ignore during the harvesting time seem insignificant when we are working because everyone wants to store the grains as soon as possible. No-till planting begins at the harvest, by setting up the combine in order to spread the crop residues as wide as the combine working width. This detail is crucial because the crops residue cover should be even in every part of the field.
In order to implement Directa (No-till system), there are 4-5 years of transition. During this period, we should pay attention to advance planning which is the key factor to a successful transition. No-till is more than just planting with a no-till planter, other factors such agrochemical mapping, soil sampling, soil fertility management, variety selection, weeds management, harvesting are also important in order to be successful.
No-tilling in more challenging conditions should be saved for later. In order to be prepared, it is also recommended to ask for help from experienced No-till professionals who have the know-how of No-till system.