Representantes
Soil is an invaluable asset for human survival, and a deteriorating resource if improperly used. In this sense, the protection and care of its surface layer must be done consciously, ensuring its sustainability, at the risk of affecting productivity and, consequently, the profits for the producer.
Agronomically, the term straw refers to plant residues that are on the soil surface and can come both from non-crop plants and from agrosilvopastoral systems.
Straw conservation on the soil surface is an important practice in the direct planting system. Among the main benefits we highlight:
>> It prevents erosion, since it reduces the impact of rain on the soil surface, especially on land with greater slope and, as a result, protects water sources from silting up and contamination, as well as reducing the risks of floods and downpours;
>> Increases the organic matter content of the soil, improving its physical, chemical and biological characteristics;
>> It maintains the humidity - especially during fall and winter, characterized by being drier seasons - dissipating the solar radiation that reaches the soil, reducing the water evaporation and the thermal amplitude - essential conditions for good crop development. It can generate a reduction of up to 20% in the need for irrigation;
>> It promotes the recycling of nutrients, since through the species with a deeper root system it is possible to reuse the nutrients already lost;
>> It promotes weed suppression, being considered one of the main strategies, when well structured. The straw limits the passage of light due to the barrier it forms, creating difficulties for seed germination, hindering the initial growth of the seedlings.
>> Increases the biodiversity, generating greater ecological balance of species and, consequently, less appearance of pests and diseases.
The choice of cover must consider periods of harsh winter, because the frost affects practically all crops, but some species or varieties suffer differently from its effects.
In regions of the Brazilian Midwest with good annual rainfall average, farmers have been investing in millet for its excellent results. Not to mention the intercropping of corn with tropical forage plants (millet, sorghum, and brachiaria). In regions of the Brazilian Midwest with lower annual rainfall, sorghum appears as a better alternative, especially for the second harvest.
In the subtropical regions of the South of Brazil, farmers have cultivated oats as a winter cover crop. The same goes for rye and ryegrass, which are equally efficient. In the case of oats, if there is frost in the area, it is no longer a good option, as it cannot tolerate extreme cold. Therefore, rye is the best option.
The choice for these grasses (oats, ryegrass, and rye) is because they produce straw that takes longer to decompose and, therefore, cover the soil for longer periods. Unlike legumes (pigeon pea and vetch), used in green manure, which decompose more quickly.
To perform the straw management, Jan developed the Tritton line and the Rotter brushcutter. The Rotter brushcutter is a versatile implement with wide application in the management of various types of crops, while the Tritton is used for shredding and flattening of the straw, producing a homogeneous cover, leaving the soil ideal for the installation of the next crop.