At the end of March 2024, during a field survey of coffee farm ecosystems in the production stage in Ea Tu commune (Buon Ma Thuot City) as part of the 2024 TOT trainer program in Dak Lak, we observed that many intercropped plants in coffee gardens were planted far too densely.
Alongside the standard coffee density of 3 m x 3 m (about 1,100 trees per hectare), other intercropped species—such as banana, pepper, cashew, guava, durian, and soursop—were planted without following any technical guidelines. These trees were found at crossroads within the plots and even directly between coffee rows, creating a dense, mixed garden.
Impact of Excessive Intercropping Density
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Such overcrowding creates intense competition for sunlight, moisture, and nutrients among different crops. This leads to poor growth and development of coffee plants and encourages the spread of pests and diseases.
Discussions with the farm owner revealed that fertilizer use for the coffee crop did not meet the plants’ nutritional needs throughout their growth stages, particularly during flowering and fruit setting. Signs of nutrient deficiency—both macro and micro elements—were visible in leaves, stems, and shoots.
Coffee leaves lacked a deep green color and sufficient thickness. Plants showed weak, uneven growth with few branches and new shoots; some leaves turned yellow, and branch tips occasionally dried out. On some trees, leaves turned reddish-brown to purplish, starting at the tips and spreading across the leaf—a typical symptom of phosphorus deficiency. Other plants showed dark yellow stripes or even brown-black streaks along the leaf edges, running from tip downward, indicating potassium deficiency.
Pests and Disease Pressure
Many coffee plants were infested with mealybugs clinging to flower clusters and young berries, sucking sap and causing fruit-bearing branches to dry. The Central Highlands is currently in its dry season; during this period, if coffee plants are weak, white mealybugs can spread rapidly. In addition, black sooty mold, pink disease, and coffee leaf rust were also found damaging some coffee trees in the garden.
A worrying sign was the scarcity of natural predators (beneficial organisms) in the coffee plot, indicating a disrupted food chain balance. In other words, chemical pesticides were likely used without observing the “four rights” (right chemical, right time, right method, right dosage), creating favorable conditions for pest outbreaks whenever the environment allows.
Root Causes and Consequences
This situation is common across many coffee gardens where owners lack technical knowledge on how to plant and manage intercropped species. Often, farmers plant based on market trends—switching from one intercropped species to another after a few years if they find it unprofitable—in hopes of gaining additional income. Over time, coffee farms become cluttered with various fruit trees, causing coffee yield and quality to decline significantly.
The Role of Proper Intercropping
Despite these problems, intercropping valuable species within coffee farms remains a highly suitable strategy and is already widely practiced in real production. Intercropping can diversify products and create positive biological interactions, proving more economically and environmentally sustainable than monoculture coffee in today’s increasingly unstable economic and natural conditions.
However, knowing how to intercrop without reducing coffee yield or quality—and ensuring long-term stability and sustainability—is a fundamental skill every grower must master and apply. Research institutions have already studied and tested appropriate companion species and planting densities and issued detailed technical guidelines. Local authorities should strengthen training, knowledge sharing, and direct guidance to farmers.
Recommendations for Mixed Coffee Gardens
For farms already overgrown with unplanned intercropping, the first step is to boldly remove fruit trees planted in the wrong locations to stabilize planting density. Provide sufficient water during the dry season using efficient irrigation methods, and improve coffee nutrition with fertilizers—particularly by increasing organic fertilizer. Organic matter helps soil remain loose, enhances both water retention and drainage, and supports an active soil microbiome. This ensures coffee roots absorb nutrients efficiently, helping plants stay healthy and resist pests and diseases. At the same time, limit the use of chemical pesticides and follow integrated pest management practices.