Do you know about soil preservation?

Coffee cultivation and soil preservation

Soil is the result of a process involving biological, physical and chemical factors during thousands of years; the layer of earth’s surface where life take place, supporting the countless forms of live spread across diverse landscapes as jungles, forests, savannas, mountains (you name it), representing an invaluable and dynamic resource that is in constant change by action of weather, natural forces and human actions as well over the pass of time. This is why soil preservation is such an important topic

Coffee soil ph

Any agricultural activity, including coffee cultivation, requires the modification of established ecosystems and native landscape to produce valuable goods for human consumption or profit; affecting the original pH, horizon depth, structure and biological dynamic equilibrium. In tropical regions where old soils as oxisols, ultisols and acrisols are common, the forest and jungles are sustained over a thin layer of organic matter (horizon “O”) that is rapidly eroded once the vegetation (many times using fire) is removed for agricultural practices, causing losses of the capacity of soil to retain water and nutrients; meaning that further addition of nutrients is required to sustain the desired crops.

The type of management applied to the land could increase or decrease the rate of erosion which the soil is summited after deforestation; starting by the implications concerning to growing short cycle (tomato, potato, strawberry, corn) or perennial crops (coffee, cocoa, tea). In the first case, the crops have a short spawn of life (generally 3-4 months), aiming to have quick earning or means of food.

These crops tend to have a higher demand of fertilizers and pesticides and water, than perennial crops, meaning that soil is more exposed to erosion caused due to wind, water flow and sunlight; at the same time, due to the application of fertilizers, soils could suffer processes of salinization or increase of acidity, causing problems related to water intake and nutrient absorption (mostly due to aluminium toxicity), respectively.

Coffee Cultivation and Soil Preservation

In the case of coffee and other perennial crops, depending on the characteristic of their region (altitude, weather) and available natural and economic resources, farmers could choose between shade-grown coffee and open coffee plantations. Soils under coffee farming systems are characterized by very low pH values (< 5.0) with high soil aluminium toxicity but the rate of erosion differs among open plantations and shade plantations.

On full exposition, farmers could yield higher productions, due to higher photosynthetic activity and evapotranspiration rates in the leaves rather than plants under shady grown coffee, but at the cost of higher demand of water and fertilizers. Plantation density and the distance between coffee plants and secondary crops/trees (banana, guano, avocado) in shade systems would also influence in the rate of erosion due to the influence of canopy and formation of natural mulching layers from decayed leaves.

Due to recirculation of organic matter among plants and soil, coffee plantations under shade systems are microbiologically more active and would require less addition of chemical fertilizers and herbicides, resulting in more convenient for smallholders in highlands that normally can’t afford the number of fertilizers for higher yield. An additional benefit of this layer of mulch is extra protection against the flow of water during heavy rain, which is one of the major forces of erosion over exposed soil, especially inland located in the side of mountains.

Some studies in Colombia, Venezuela and Indonesia have shown soil losses ranging from 0.2 to 8.9 t ha–1yr–1 in established coffee plantations, where the shade plantation are the ones with the lowest affection.

This is of particular interest due to the increasing pressure that climate change is putting over farmers in developing countries, that by taking advantage of biological processes could reach a balance between productivity and limitations concerning to inputs for the farm and also water availability for farmers and communities. Still, climate change is not the only issue that is concerning farmers and coffee industry about soil preservation.

Nowadays, agriculture doesn’t just respond to what we need to eat, also does according to changes on the market, which has proved to be a strong force that could cause big changes over the landscape of rural areas on few years, bringing with them the negative consequences of farmers moving from coffee to other crop, with higher requirements on inputs.

As a counteracting force towards climate change and uncertainty of the market; awareness among costumers (industry and final consumer) would play a huge roll in the future of coffee cultivation for producers worldwide, since through the demand of organically grown coffee, products with fair labor certification and other practices originated from the market, could be used to promote sustainable strategies aiming to soil preservation and for instance water resources through organic cultivation of coffee and other perennials.

Edoardo Zanato

I am an Italian coffee lover that pushed for the love of this “amazing drug”  decided to come to London to study about coffee and its different extraction procedures and tastes.