Important to the quality of the coffee is the health of the plant itself. A healthy plant is one where all the necessary conditions/nutrients are supplied in the correct ratio such that the plant can utilize them all without any deficiencies or overabundances. Too much water (leading to oxygen starvation) can be just as harmful to plant health as potassium deficiency. Any one condition or nutrient out of proportion with the others can be detrimental to seed quality and yield.
The Environment: Like any agronomic crop, coffee plants require sun, water, soil nutrients, air, and the correct climate.
- Sun: If all of the arabica’s needs are met in abundance, it is possible for runaway growth of the plant itself to take energy away from the seasonal fruiting and reproductive cycle. This is a consequence of the ancestry of this plant variety, which can be traced back to Ethiopia where sunlight was always a naturally limited resource by the shade generated by the forest canopy above. In agriculture, optimally, one resource is limited just enough that runaway growth doesn’t take away energy from the reproductive cycle, but not limited to levels where energy availability and the natural aging process of the coffee plant are disrupted. For C. arabica, over exposure to the sun can cause UV damage to the leaves and cause lowered yields and quality. For this reason, high quality C. arabica is usually shade grown. However, sun is also extremely important because it supplies the energy needed to preform photosynthesis (discussed more below) and over shading can also cause quality and yield problems.
- Water: Essential to life, water is the circulatory medium of plants. Evaporation of water from the leaves drives a pressure differential all the way to the roots sucking up nutrients and moving them through the plant to be utilized in the new growth or reproductive areas as needed. Permeability and moisture content (geology) of the soil play an enormous role in health and productivity of an agriculturally cultivated plant, as does the quality of water and natural precipitation schedule.
- Soil Nutrients: The availability of macro nutrients such as Potassium, Nitrogen, and Phosphorus are key to the formation of new plant grown and deposition of sugars and lipids in the reproductive cycle of the plant. If the proportions of these nutrients are not ideal or sufficient for healthy plant growth, fertilizers are commonly utilized. Responsible use of fertilizers to avoid over contact with surface water runoff is a major concern in the developing world. The pH of the soil directly affects the energy required by the plant to extract and absorb nutrients from the soil.
- Air: A plant needs energy to grow and reproduce, but where does the energy come from? It comes from the use of sugars that are photosynthesized within the plants cells. These sugars are the product of the electromagnetic energy in sunlight and carbon dioxide which are combined in the presence of chlorophyll, in a naturally occurring process called the Calvin Cycle, producing glucose, oxygen, and water. Let’s be honest, this is the coolest thing ever.
- Climate: Ambient temperature, temperature variation, altitude, season length, humidity, latitude, slope angle, terrain profile, cloud coverage, wind, and wind direction all play significant roles in insuring plants can perform the correct amount of seasonal photosynthesis to generate the sugars and absorb nutrients required for healthy, high quality, and high yielding reproductive cycles.
Still haven’t had enough? Check out Coffee Agriculture Science Level: Genius