Weed management in coffee

At the Weed management in coffee is recommended to integrate manual, mechanical, chemical and biological, correctly and at the appropriate time, to enable the reduction of the infesting population, rationally and without economic and environmental losses.

According to the level of infestation, the predominant species and the size of the plants weeds, competition may occur with coffee crops for water, light and nutrients. That It harms the vegetative and productive development of the coffee plant and makes it difficult to implement farming practices.

When the biomass of these weeds is managed, benefits for the crop occur coffee plant as protection of coffee plantation soil from erosion, reduction of moisture evaporation, recycling of essential nutrients, supply of organic and improving soil structure.

The practice of control of weeds is important in coffee production, as influences the productivity, costs, and profitability of the crop. It becomes important that this control with application of good agricultural practices contribute to sustainability of culture, through the rational use of inputs and services, lower environmental impact, reduced costs, increased profitability and better social conditions of the workers.

However, the application of Weed control without due criteria causes negative effects on the farm. The inappropriate use of herbicides cause damage to the coffee plant, crusting and surface erosion of the soil, reduction of organic matter and presence of resistant species. O Excessive mechanized control promotes weed survival, formation of a dense layer and decreased stability of soil aggregates.

The application of unified and repetitive methods is also not efficient in controlling plants weeds in coffee plantations and cause negative effects in the growth and yield of the crop, resulting in losses. In this sense, integrated coffee weed management controls these species through the combination, succession and rotation of different methods of control in a given time and space on the plot.

The composition of weed plants in coffee plantations depend on climatic variations, characteristics soil, type of crop and management system, which influence the germination of the seed bank and the infestation rate of the species in a certain period on the farm.

The pushing of the weed population per coffee plot identifies the species predominant species and their biological characteristics, supporting the taking of decision on which management strategy will be most appropriate.

The main coffee weed species are classified according to their growing season. occurrence (dry or rainy), biological cycle (annual or perennial) and plant morphology leaf (narrow or wide).

Management Integrated Weed Management

Weed management aims to The objective is to have better coexistence and less competition with the coffee plant. It is recommended control plant biomass in between the lines, and especially in the coffee planting lines, which must always be carried out clean to avoid some competition.

Reduction of infestation or re-infestation of weeds in the coffee plantation must be carried out even before they can produce seeds, that is, prior to its dissemination stage. Nonetheless, due to the diversity of vegetative and reproductive cycles of species, as well as as well as variation in the expression of the seed bank, its management becomes difficult, requiring greater common sense in decisions.

Integrated weed management in coffee is characterized by the interaction between control practices and other culture management inherent to soil conservation, pruning scheme, control phytosanitary and nutrient replacement, for a favorable coexistence of culture with weeds, without worrying about eliminating them immediately.

The decision to apply integrated management depends on the characteristics of the crop (size of the area, spacing of between the lines, age of the coffee plantation and size of the coffee trees); plant infestation weeds (main species, degree of occurrence, plant size and stage of development); environmental conditions (land topography, water supply, climatic aspects and type of soil) and the producer's resources (available workers, machines and implements, financial conditions and purchase of products).

Weed management in crop coffee can be understood as the set of manual, mechanical, chemical and biological, applied correctly and at the appropriate time, which rationally enable the reduction of the weed population without harm economic and environmental.

Control methods manual most used in coffee farming are the weeding with a hoe and mowing with scythe. A weeding with a hoe is the main thing in coffee tree lines, complemented by other methods between the lines. Although efficient, manual weeding has low yield and onerous cost, whose labor is not always available in sufficient quantity and at the desired time. Using manual weeding is the appropriate method for areas with higher slope at 20%, crops with dense spacing and coffee plantations in formation. Brush with low or low cutting sickle reduces the size of weeds in between the rows of coffee trees, forms mulch, increases organic matter and nutrient on the soil surface, in addition to contributing to erosion control between the lines, especially on terrain with greater slope. As Alternatively, you can use a motorized backpack brushcutter, driven by a motor two-stroke gasoline, with options of different brands and specifications, with various types of cutting blades.

You mechanical control methods of weeds in between the lines of the coffee plantation requires the provision of machines and implements, open space between the lines and flat terrain or with a slope of less than 25%. In line with culture is often controlled by the burial of small seedlings, caused by soil displacement in the passage of implements. This method replacing or complementing others, it presents higher yields and greater savings, mainly on large plantations. In the operation, micro-tractors can be used, narrow-gauge and coffee-type tractors, which drag implements such as cultivator, brush cutter and brush cutter, although at a higher cost in acquisition and difficulty in hiring specialized labor.

The method chemical control of coffee weeds consists of use of herbicides, applied to vegetation or soil, causing disturbances physiological, which respectively cause the death of plants or inhibition of germinations. The properties of the mode and mechanism of action of herbicides in plant and persistence and degradation in the soil are fundamental for the monitoring the effects on the coffee plantation and the environment.

To apply chemical control to coffee, it is suggested to consider characteristics of crown growth and tree height coffee crop in formation and production, the type of pre-emergent herbicide and post-emergence and the population of weed species, their cycle biological and leaf type.

Pre-emergent herbicides have residual effects and are applied to clean soil when weeds have not yet emerged. Post-emergent herbicides act on plants weeds already emerged or established, through contact action, with the death of plants occurring within a few hours up to two days after application, or translocation action or systemic with plant death in one to three weeks, depending on the herbicide, species and physiological stage and growth of the weed.

The herbicide mixture is the combination of two products with the aim of expanding the spectrum of action on the weed population or controlling some species tolerant to the main herbicide. It is possible to take advantage of the synergistic effect of the mixture on one or another weed with lower susceptibility and reduce the residual effect. This mixture can be ready in several commercial formulations or be prepared in crop in the sprayer tank, according to recommended dilutions individual.

As for weeds, there are species with an annual biological cycle, which multiply by seeds every year, control of most species requires the application of lower doses of herbicides post-emergent contact action. As for weeds with a perennial biological cycle, they multiply by seeds or vegetative parts, having a long life, high size and greater rusticity, whose control requires the application of larger doses of systemic post-emergent herbicides. In analyzing the specific conditions of each coffee plot, the indication of the most suitable herbicide is displayed through the predominance of narrow or broad leaf weeds, culminating in the definition of the active ingredient and doses of the product recommended.

The tractor-driven mechanical sprayer has a drive hydraulic with pump connected to the power take-off. Distribute the herbicide mixture under pressure for a back bar containing spray tips. Your tank has capacity for 200 liters of solution or 400 liters of solution, whose connections with the spray tips provide options for applying herbicide in any strip of the crop in the row or between the rows. This equipment features high operational performance in medium and large coffee plantations, with greater line lengths. Usage limitations occur in crops with steep slopes and in dense plantations, in addition to requiring greater investment and specialized workers. To protect coffee trees from herbicide spray drift, protective flaps should be used over the spray tips or over the the entire application bar, or use special “anti-drift” spray tips or with minimal drift.

The control method biological by allelopathy can maintain the weed population at a low level that does not cause economic damage to the culture. This method results from the interaction between plants caused by allelochemicals or chemical substances secreted by the aerial part or underground plants in development or released by waste in decomposition. Both promote inhibition or preventing seed germination, reducing seedling growth and influence on symbiotic processes.

The use of allelopathy in controlling weeds in coffee is basically characterized by the use of mulch and by cultivating living cover between the crop rows.

Mulching makes it possible to reduce weed infestation by competition through the physical effect of shading and action of chemical substances leached into the soil by the action of rains. This practice is in common use among coffee growers, through the use of weed vegetation and species cultivated between rows that are eliminated with herbicides or cut with a brushcutter, resulting in a layer of straw over the soil. It is also checked the use of the bark of coffee deposited throughout farming, but with questions about its viability due to supply factors, cost and interference with weeds.

The living cover consists in the intercalation of annual subsistence crops and of green manure cultivated between the rows of coffee trees, or even, in the intercropping of perennial crops cultivated in the coffee tree lines. Among the cultures of subsistences stand out rice, beans and corn, whose number of rows depends on the spacing of the coffee plantation, a strip free of planting with a width of half a meter must be maintained on each side between the lines of coffee trees and the intercropped crop. The cultures of green manure are species of grasses and legumes that are managed adequately promote the suppression of weeds due to the influence of soil cover and the production of biomass, through shading or the action of its allelochemicals. As Perennial crops can be intercropped with a variety of fruit plants.

options of Management

On a coffee farm in training and in production, several integrated management options can be used weed plants. Mowing reduces the size and competition potential of plants weeds, keeping the vegetation alive and starting a new growth cycle. Herbicide non-selective post-emergent kills all vegetation, contributing to forming a cover dead.

Both practices protect the soil from the impact of raindrops, solar radiation and winds.

The application of post-emergent herbicides on weeds at a more advanced stage of development promotes the achievement of a thick dry layer of straw, which protects the soil from erosion during the rainy season and provides retention of moisture in the soil during the dry season. It is necessary to remain careful so that there is no competition with coffee trees in the growth, flowering and fruiting phases, with the need for carry out up to two to three applications of control.

At the beginning of flowering, coffee trees require good growing conditions soil moisture to ensure high rates of initial transformation of flowers in fruits that result in “chumbinhos”, preserving productivity expected. At this stage, the practice of mowing can be a palliative, as the exclusive cutting of the aerial part of weeds allows competition to continue for water and nutrients, with the application of post-emergence herbicides being recommended.

Before harvesting, after the rutting stage, it is recommended to apply herbicide pre-emergent to keep the crop clean, facilitating farm activities harvesting and collecting the fruits. At the end of the harvest and after spreading, a post-emergence herbicide mixture should be applied to promote the formation of a layer of mulch of the soil.

The periodic rotation of the application of different chemical groups of herbicides, with active principles of mechanisms and differentiated modes of action, inhibits the selection of weed species resistant and microorganisms, improves control efficiency, prevents unnecessary application or excessive dose and reduces the impacts caused on the environment.

It appears, therefore, that the adoption of a single management is not recommended for efficient control of weeds in coffee, due to the diversity of this population. There is no standard recommendation for integrated management. It is recommended that it be diverse and dynamic, like the infestation itself of weeds, always seeking to balance control with benefits for the farming. Every year, all types of management must be carefully reviewed, with evaluation of the effects on soil and crops, as well as their technical and economical, respecting the conditions of each coffee plot.

Article published in issue 226 of Cultivar Grandes Culturas, March, 2018.