Applying ancient water conservation techniques to grow rainfed coffee in Yemen’s mountain regions

Abdulrahman Al-Eryani

Yemeni agriculture has long depended on sustainable and efficient water conservation and soil management practices – largely in the form of terraced land. Yemen is one of the most extensively terraced areas in the world, (Varisco, D. M. 1991). This has enabled large populations to not only survive, but flourish and build a unique civilization, adapted to its predominantly arid and semi-arid climate. Most, if not all, other ancient civilizations thrived along major rivers, where water is more available.

Still dominant features of steep mountain and deep wadi areas, Yemen’s arable terracing systems, dating back to at least the 3rd millennium BC (Wilkinson, 1999), have hugely contributed to the country’s human development. Without these systems, it is difficult to imagine a pathway for sustaining such large populations for so long.

However, according to the United Nations Development Programme’s report ‘A Holistic Approach to Addressing Water Resources Challenges in Yemen’, the country has long been “living above its water means and using its non-renewable groundwater at an unprecedented and irreplaceable pace”. The report notes that in 2022, around 84 percent of the country’s water use was for agriculture, highlighting the critical need to apply water conservation techniques wherever and however possible.

Innovative application of traditional techniques

The benefits of terracing systems are immense and they have a major role to play in making careful use of the valuable and scarce water available. They function as micro-dams which capture and store rain and water runoff, and slow water movement, allowing ground water to recharge in a highly effective way. They also stabilize the land preventing soil erosion, create different sized flat areas for food and fodder crop production, and create new healthy soils.

In more recent times, farmers in Bani Ismael of the Haraz district in the Western mountains of Sanaa Governorate, have taken the principles of terracing one step further. On very steep mountain sides that range in elevation from 1000m to more than 2000m above sea level, coffee growers have built thousands of terraces, most of which have narrow but deep planting pits (about 50cm). In addition, they cover the soil around each pit with stones. These pits and the stone mulching around it are designed to maximize the collection of the somewhat erratic rainfall and capture the natural dew forming every morning to cultivate coffee.

Benefits of terracing for coffee production

The design of the terraced pits mulching with stones have multiple benefits for farmers:

1.     They reduce soil moisture loss and evaporation.

2.     They prevent weeds from growing and competing with coffee plants.

3.     During humid summer nights, a significant quantity of dew collects on the terrace’s colder stone surfaces, which seeps into the pits in the early morning to irrigate coffee plants.

4.     During cooler winter nights, the stone and the deep pits protect the plants from colder temperatures.

In addition, farmers found that the coffee plants produce more coffee cherries and better-quality coffee beans.

This method has now spread to at least three similar districts in the western mountain ridges of Yemen Raymah, Ottmah and Mahoyt.

Assessing the impact

Whilst these ancestral techniques of terracing, stone pits and stone mulching for water harvesting, and water conservation are well known in other regions – especially in Central and south America – to my knowledge there has been no scientific assessment of the viability and impact of using terraced pits and stone mulching, such as those in Yemen for coffee growing. However, the huge effort that farmers continue to take to build and maintain these terraces, and the reported benefits to the quality and quantity of coffee produced is a testimony of their effectiveness. I believe that the scale, sophistication, and outcome of this coffee growing methods applied by Yemeni farmers provides the case for a field study to assess the true value and potential for learning from this unique technique, inspired by the practices of our ancestors.

References:

Wilkinson, T. (1999) “Settlement, soil erosion and terraced agriculture in highland Yemen: a preliminary statement”, Proceedings of the Seminar for Arabian Studies 29: 183-191

Varisco, D. M. (1991). The future of terrace farming in Yemen: a development dilemma. Agriculture and Human Values, 8, 166-172.