Coffee News: from Seed to Cup

Coffee Farming Guide: How to Improve Soil Quality

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Growing strong, healthy coffee trees involves balancing several elements: sun, water, wind, and nutrients from the soil. However, when it comes to soil quality, there are many misconceptions.

Healthy soil is a fundamental aspect of coffee plant production, and as a farmer looking to get the maximum quality and yield from your crop, you can’t afford to ignore it. 

In order to make sure you get the best possible outcomes from your farming efforts, you need to ensure that specific nutrients are present in your soil in the correct quantities. Here’s what these nutrients are, how they can impact your soil quality, and how to avoid mistakes that could negatively impact your coffee production.

Lee este artículo en español Cultivo de Café: Cómo Mejorar la Calidad Del Suelo

Healthy coffee trees in Minas Gerais, Brazil. Credit: Alessandro Marcos, Coopervitae

The Importance of Macro & Micronutrients

There are 17 essential elements required for successful coffee plant development. A shortage of any one of them can negatively impact your plant development and yield. 

Coffee plants receive carbon, hydrogen, and oxygen from the surrounding air and water, and receive nitrogen, potassium, phosphorus, calcium, magnesium, and sulfur from the soil where they’re planted. These nine elements are called macronutrients, and large quantities are needed for a coffee plant to thrive.

Certain micronutrients are also needed by coffee plants, but in much smaller quantities. These include iron, zinc, copper, manganese, boron, chlorine and molybdenum. Some plants also require nickel.

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Coffee cherries ripen on the branch. Credit: Alessandro Marcos, Coopervitae

Creating The Perfect pH For Coffee Growth

A healthy coffee plant requires more than just nutrients. Its acidity also needs to be at an optimal pH level, which is between 4.9–5.6 pH. Between these levels, the plant is better able to absorb nutrients, resulting in more coffee cherries and less pest and disease-related issues.

If your soil is too acidic, you can neutralize it by adding calcitic lime, or dolomitic lime if it also lacks magnesium. Low acidity can also be an issue, and is usually balanced out through frequent fertilization.

Coffee fields in Nova Resende, Brazil. Credit: Alessandro Marcos, Coopervitae

Creating The Ideal Soil Conditions

Professor João Batista Pavesi Simão from Brazil’s Instituto Federal do Espirito Santo has been developing applied research to coffee since 2005. He attributes much of Brazil’s success as a coffee-producing nation to their analysis of soil properties and factors such as particle physics, chemistry, and biology. 

”Adequate soil for cultivating coffee has to be deep, a little over 1.5 meters, free from physical impediments like rocks… porous, and with a density of 1.5 grams per cubic centimeter,” he tells me. 

How much water your soil receives is just as important. Plants absorb both water and nutrients through their roots, so too much or too little water can be harmful. Proper drainage is important, and this will change depending on the soil’s texture. The ideal texture for successful coffee production is a combination of sand and silt, with a bit of clay added in. 

Farm in the mountains of Espirito Santo, Brazil. Credit: Ivan Laranjeira Petrich

How to Use Fertilizer For Coffee Farming

While it’s true that adding fertilizer to soil will benefit most plants, without knowing what the soil lacks makes choosing the right type and volume of fertilizer challenging. For example, a coffee plant will require nitrogen for photosynthesis. 

However, if it receives too much of it, it will need additional phosphorus, calcium, and potassium to compensate, which in turn can lead to the plant developing unusually high caffeine levels. There’s no good way to apply corrective measures without knowing what you’re dealing with in the first place.

Producer Alessandro Marcos with a coffee plant on his farm in Southern Minas Gerais, Brazil. Credit: Alessandro Marcos, Coopervitae

How To Analyze Your Soil Content

So, how can you find out more about your soil quality?

While you could adopt a “wait and see” approach, by the time the deficiency becomes apparent it might be a case of too little, too late – at least for that harvest. Without analyzing your soil first, there’s no way to know which nutrients are lacking or what needs to be corrected. 

According to Professor Simão, it’s best to regularly consult with a professional agronomist or send soil samples to be analyzed by a reputable laboratory or nearby college’s agricultural department. While there can be a cost associated with this, the return on investment makes it worthwhile.

The Specialty Coffee Association also mentions that “some agronomists recommend having soils as well as foliar tissues analyzed multiple times a year to assure accurate nutrient management.” 

However, while monitoring soil nutrients isn’t a DIY activity, you can easily check the pH of your farm’s soil using pH test paper or a handheld pH meter. Since acidity/alkalinity corrective measures are semi-permanent at best, it’s advisable to do this at least once a year in each field used for coffee production. It’s also a good idea to run tests prior to planting in a new area, so you can treat the soil preemptively if necessary.

Once you’ve undertaken a more in-depth analysis, you’ll no doubt be provided with professional recommendations on different fertilization techniques that can be applied during different stages of a plant’s life cycle. 

For yields and harvests that improve year after year, Professor Simão recommends that farms “keep data annually and establish procedures for fertilization and correctives.” 

Sítio Prata in Nova Resende, Minas Gerais, Brazil. Credit: Alessandro Marcos, Coopervitae

There are many variables that impact the health of a coffee plant. Creating the ideal soil conditions for growth could result in coffee cherries that are bigger and sweeter, carrying the potential for higher cupping scores and better market prices. 

Monitoring your soil’s pH and working alongside an agronomist will allow you to reap the benefits of good soil management practices – which will benefit your farming long into the future.

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Written by Raphael Jonsson Oliveira. All quotes from Professor Simão translated from Portuguese by the writer. Feature photo credit: Alessandro Marcos, Coopervitae

Please note: Before implementing the advice in this article, we advise also consulting with a local technical expert, since differences in climate, soil type, varieties, processing methods, and more can affect the best practices for production and processing.

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