Weed management in coffee

The coffee tree is a perennial crop that is very predisposed to competition from weeds, which can result in direct losses due to reduced growth and productivity, as well as indirect losses, as these plants make management difficult and serve as hosts for pathogens or vectors of important diseases. Its control, although necessary, requires a lot of discretion to preserve profitability in a sustainable way.

Each Agricultural culture presents a different level of sensitivity to the presence of weed plants, which depends mainly on the intrinsic characteristics of each species of cultivated plant and its cultivation system. The plant of coffee and its form of cultivation present, for example, some peculiarities that favor the infestation of weeds and, or, make the crop sensitive to harmful effects on the weed community.

Initially, It is important to remember that the coffee tree is a perennial plant. This means that your life cycle exceeds two years. In fact, the coffee tree is a plant that lives many years, and its productive life can extend for more than 30 years. Such as most perennial plants, the initial growth of the coffee tree is slow, compared to that of annual plants. Thus, the formation of its crown occurs slowly after the transplant. Consequently, there is not good soil coverage during crop formation phase, a period that lasts from 18 months to 24 months after transplanting.

That Rubiácea (botanical family to which the coffee tree belongs) is traditionally cultivated in parallel planting lines, 3,0 m apart from each other at 4,0m. The spacing between one plant and another within the planting line varies generally 0,5m to 1,0m, depending on the cultivar and cultivation system. Soon, the wide cultivation spacing, associated with the relatively slow growth of crown (whose diameter in the adult phase practically does not exceed 2,0 m), leaves a large area of ​​exposed soil in the crop, especially in the initial stages of cultivation, thus allowing strong infestation and growth of weeds.

Soon after transplanting, the coffee seedlings, whether from bags (seedlings clod) or tubes have an incipient and superficial root system, with a limited capacity to absorb nutrients from the systems aggressive roots of weeds, especially those with an annual cycle fast growing.

O planting of coffee trees in the field, especially in rainfed areas, is carried out usually at the end of spring, therefore at the beginning of the rainy season (November), a time when there is greater water supply. Likewise, during this period temperatures occur relatively high. All these factors contribute to stimulating germination of weed seeds and, mainly, for their growth quickly, which worsens the harmful effects of these plants on the coffee plant.

Your Planting takes place in holes or furrows properly prepared for this purpose. Adds organic matter (which is often the main source of plant seeds weeds), fertilizers and correctives which, together with the great upheaval of soil for planting operations, stimulate or enhance the infestation of weed plants, very close to the coffee tree stem, aggravating the process competitive.

During During the adult phase, crops in production commonly go through two processes necessary for the harvest, which are the rutting (in pre-harvest) and the spreading of the “speck” (after harvest). These practices consist, respectively, of remove and return plant residues under the coffee tree canopy, to allow the collection of coffee beans that fall (naturally or during harvest) to the ground. At the same time as these are practices that end up carry out direct mechanical control of any existing weeds, especially under the coffee tree canopy, they also spread weed seeds by the crop, which can increase the reinfestation of the area, as soon as it starts the next rainy season.

Sockets together, these characteristics of coffee growing and the coffee plant itself allow weeds to infest crops, damaging their growth and productivity. This occurs basically due to direct competition for resources, such as water, light and mineral nutrients, reducing their supply to the coffee plant, especially in the initial stages of cultivation, as demonstrated in several studies scientific. But the losses don't just lie there. The weeds can compromise crop management, for example, reducing crop efficiency distribution of fertilizers and correctives, the application of pesticides to control phytosanitary protection, as well as the collection of coffee from the ground during harvest. However, weeds can host pathogens or vectors of important diseases of coffee plants. Therefore, weed control is a common practice during all stages of coffee production on the farm.

O control begins early, even when cleaning the area for construction of the nursery and acquisition of land and organic matter (manure) for the production of seedlings. In the nursery, the weeds that germinate next to the coffee seedlings must be eliminated. The area in which the crop will be implemented must have the partial vegetation (only in the planting line) or completely removed, depending on the cultivation system and region. Soon after transplanting and in first 18 months that follow, the crop goes through a period of high competitive sensitivity, and therefore integrated management of weeds, appropriate for each situation. Finally, in crops in production or in those pruned, sustainable practices must be carried out weed management to mitigate competition and ensure growth and the productivity of the crop over the years, as, after all, it is of a perennial culture. It is important to note, however, that all control practices used in coffee farming must be very well positioned by the adoption of integrated management to ensure, among several aspects, the environmental benefits that weeds can add to Agriculture.

It is clear, therefore, that plant control practices weeds are necessary to guarantee satisfactory productivity. Still, have an associated cost. Therefore, they are directly related to the economic sustainability of coffee production. This, therefore, among the various factors that affect the profitability of coffee (e.g. selling price), increased productivity (measured in bags of 60 kg of processed coffee per hectare) in parallel with the reduction in production costs, together, they tend to increase the profitability of the activity. Consequently, when weeds (and their control) are considered in the production, can compromise the profitability of coffee farming both by reducing productivity as a result of competition, as well as by increasing the cost of production, as the producer will need to disburse financial resources for the control. In this way, it is possible to deduce that the practices used in the weed control in coffee crops must be appropriately balanced to reduce competition to a minimum, to enhance productivity, but, at the same time, at the lowest possible cost.

AND However, caution is needed when thinking about reducing the cost of controlling plants in the coffee tree, as this can have very negative impacts on the productivity. To illustrate, consider the cost of operations mechanized control in highly mechanizable crops (e.g. crops in Cerrado Mineiro). In these areas, the cost of labor, herbicides, oil diesel or maintenance of implements such as brushcutters, brushes or applicators herbicides is very low. However, it cannot be neglected, because, if Otherwise, productivity losses due to competition will significantly reduce the profitability of coffee production.

AND possible to conclude that the management of weeds in coffee plantations should be carried out with great care, especially to compensate for the great sensitivity of the coffee tree to the presence of weeds. Unfortunately, despite the great economic and social importance of the coffee tree in Brazil and the world, there is a certain lack of scientific information on the various aspects related to this area of ​​knowledge, when compared to other equally important cultures. This occurs for both (Coffeea arabica) as for the (Coffea canephora), and for the latter (here in Brazil represented by the conilon variety) are even scarcer. However, coffee is produced in Brazil in different regions, under different cultivation systems. Therefore, the methods of weed control employed by coffee growers may vary considerably between crops, which is necessary to adapt to the realities of each crop.

Claudius Pagotto Ronchi, UFV

Article published in issue 230 of Cultivar Grandes Culturas, July 2018.