Ethiopia is traditionally classified into three major agro-ecological zones: Dega (highland), Woina-Dega (mid-highland), and Kolla (lowland)
The Dega zone is a zone of highlands having relatively higher temperature and lower altitude compared to other highland areas. It is long inhabited and has dense human settlement due to reliable rainfall for agriculture and absence of vector-borne diseases
The Woina-Dega zone is a zone of mid-highlands with two growing seasons and includes most of the agricultural land in Ethiopia
The Kolla zone is the climate of the hot lowlands with an altitudinal range of 500 to 1500 meters above sea level. It has an average annual temperature range between 20°C and 30°C, and although mean annual rainfall is erratic, it can be as high as 1500 mm in the wet western lowlands
In terms of plant diversity, a study found that the Woina Dega agroclimatic zone had the highest species diversity (203 species), followed by Kolla (130 species) and Dega (88 species)
Another study covered urban, peri-urban, and rural settings of Dega, Weyna-Dega, and Kolla and found that home-gardens in Ethiopia have a diverse range of crops, including cereals such as tef, wheat, barley, sorghum, maize, and millet
A report by the Food and Agriculture Organization (FAO) also notes that different crops are grown in different proportions in the Woina Dega and Kolla areas
In summary, the main differences between Dega and Kolla crops and plants are due to the different agro-ecological zones they belong to. Dega is a highland area with reliable rainfall, while Kolla is a lowland area with erratic rainfall. As a result, the crops and plants grown in these areas differ based on the climate and altitude.