EN 
PT_BR 
The machines leaving after the harvest. sugarcane This does not necessarily mean that the next step is soil decompaction. Before subsoiling or scarifying, it is necessary to confirm whether there is compaction capable of limiting root development, identify its depth, and verify that the soil moisture allows for efficient operation.
Soil compaction is a problem associated with increased soil density and resistance to penetration, accompanied by a reduction in the volume of pores responsible for water and air circulation. In sugarcane cultivation, the most affected layers are usually between 0.10 and 0.40 meters deep. Heavy machinery traffic is one of the main causes. Harvesters, transshipment vehicles, tractors, and trucks repeatedly circulating through the field, especially when the soil has high moisture content, can aggravate the problem.
Since sugarcane remains in the area for several harvests, compaction can compromise not only a crop but also the development of the ratoons and the longevity of the sugarcane field. The goal of post-harvest management is to reduce physical limitations where they actually exist, promote water infiltration, and preserve roots, straw, and soil structure.
Signs in the field need to be confirmed.
Several symptoms may raise suspicion of soil compaction. These include sprouting failures, yellowing plants in certain parts of the field, puddles of water after rain, slow infiltration, surface runoff, and roots concentrated in shallower layers. Differences in growth between trafficked and untrafficked areas can also indicate physical problems in the soil.
These signs, however, are not sufficient to automatically determine the need for mechanical intervention. Diagnosis may include trenching, crop profile analysis, root assessment, and the use of a penetrometer, an instrument that measures soil resistance to penetration.
Observing the roots also provides important information. When they deviate from their growth path or thicken upon encountering a particular layer, there may be a mechanical impediment.
The area's history should also be factored into the analysis. Frequent traffic on wet soil, sugarcane performance over several harvests, and analysis results help determine if there is a real need for intervention.
Subsoiling and scarification have different functions.
When the diagnosis confirms the need for soil decompaction, the next step is to define the appropriate equipment. The subsoiler usually works at greater depths and is used to break up deeper compacted layers. This operation requires more tractor power and, consequently, higher fuel consumption.
The scarifier works at intermediate depths, aiming to relieve subsurface compaction and improve aeration. Its power demand is generally lower compared to deep subsoiling.
Therefore, there is no single choice for all areas. The equipment needs to be defined based on the depth of the compacted layer, the management history, the stage the sugarcane field is in, and the capacity of the available machines.
Humidity determines operational efficiency.
Even when compaction is proven, it is necessary to observe the soil condition before the equipment enters. In excessively dry soil, the rods may only cut through hardened blocks and require a large amount of energy, without causing adequate disruption of the compacted layer.
At the other extreme, working with excess moisture can cause the soil to deform plastically and partially close its pores after the operation. The desired situation is called friable moisture. This is an intermediate condition in which the soil breaks down into aggregates without turning to dust or forming plastic masses.
In the field, a simple assessment can help. A sample that crumbles easily indicates a very dry condition. When the soil forms a plastic, shiny cord, there is excess moisture. The most suitable condition occurs when it can be molded but breaks with light pressure.
The calendar should track rainfall and harvest.
Management also needs to consider climate changes throughout the year. The material does not specify a particular month for decompaction because conditions vary between regions, crops, and plots. During rainy periods, there is a greater possibility of the soil being too wet. Under these conditions, in addition to reducing the efficiency of the operation, heavy traffic can generate new compaction.
The transition periods between rainy and dry seasons often provide better opportunities, as they can allow the soil to reach a friable condition. In very dry periods, the operation tends to be efficient only when there is still adequate moisture at depth or after localized rainfall.
The decision also needs to align with the harvest schedule. Any operation should take place within an appropriate window after the machines have left the operation and before weather conditions that reduce their efficiency.
Not all areas need to be decompacted.
Automatically associating decreased productivity with the need for subsoiling can lead to unproductive operations. The material reinforces that not all areas or cuts require this type of intervention. After harvesting, the producer should assess whether there was heavy traffic on wet soil, whether the diagnosis confirmed a compacted layer in the root zone, and whether the moisture allows for work.
It is also necessary to consider the age of the stubble. In young and productive stubble, a more aggressive operation increases the risk of damaging the roots. In areas close to the replanting phase, more extensive interventions can be planned for a later time.
The material clearly states that soil decompaction does not need to be done every year. It is a corrective measure that should be used when the diagnosis identifies compaction that limits root development.
Preventive management helps reduce the problem.
Maintaining crop residue is one of the practices that should accompany soil management. The residues left after harvesting help protect the surface against the impact of rain, reduce temperature fluctuations, and contribute to an increase in organic matter. Another point is controlled traffic. By delimiting fixed lanes for the circulation of machinery, the system reduces the total area subjected to the weight of the equipment. If intervention is necessary, it can be directed to the most affected lanes.
Soil decompaction can also be planned in conjunction with soil correction and fertilization practices, when technically indicated. For areas with severe compaction, a deeper intervention may be more appropriate during sugarcane field renovation. Performing the operation at the wrong time can have the opposite effect to that desired. Among the risks are increased fuel consumption, machine wear, little physical improvement of the soil, creation of new compacted areas, and cutting of active roots.
