The Role of Agro-ecological Zones in Agriculture

What are Agro-ecological zones?

Agroecological zones are geographical areas exhibiting similar climatic conditions that determine their ability to support rained agriculture.

FAO on the other hand defines an Agroecological zone (AEZ) as a land resource mapping unit, defined in terms of climate, landform and soils, and/or land cover, and having a specific range of potentials and constraints for land use.

Most people think that crop production requires only farms and funds, however, there’s one more thing they forget. It’s the ecology of their farmlands, the Agroecological zones.

According to FAO, the essential elements of the core applications of agro-ecological zone comprise:

Land resources inventory
Inventory of land utilization types and crop requirements and
Land suitability evaluation.

However, our interest is in crop requirements and land suitability for crop production. Now, let’s begin this way …

Factors affecting Agroecological Zones

Agroecological zones (AEZ) are influenced by several factors. The key factors are:

Altitude
Temperature
Humidity
Rainfall amounts
Seasonality
Distribution during the growing season and
Latitudes at a regional scale

Remember the aforementioned factors as we continue. Suppose we assume all the socio-economic factors to be constant. In that case, agriculture is majorly affected by environmental factors which are: climate, topography/relief (high lands, sloping lands or lower lands) and soil fertility.

However, the climate is made up of, among others; temperature, humidity and rainfall are also the major factors influencing agroecological zones (AEZ) as shortlisted above. If you review the factors influencing crop growth and development you will find out that it is temperature, moisture/water/rain, light and soil fertility (plant nutrients).

What am I trying to say?
My point is “the performance of the crops depends on the agro-ecological zone”, and that “not all crops can do better in all agro-ecological zones”. So you must choose carefully either the crops to cultivate in your agro-ecological zone or the agro-ecological zone for the crops you want to produce.

You understand now, right?

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The knowledge of agroecological zone is essential to crop growing periods and provides a way of including seasonality in land resource appraisal. In many tropical areas, conditions are too dry during part of the year for crop growth to occur without irrigation, while in temperate climatic regimes crop production in winter is limited by cold temperatures.

The growing period defines the season of the year when both moisture and temperature conditions are suitable for crop production in that particular zone.

The growing period provides a framework for summarizing temporally variable elements of climate (in a particular agroecological zone), which can then be compared with the requirements and estimated responses of the plant.

Such parameters as temperature regime, total rainfall and evapotranspiration and the incidence of climatic hazards are more relevant when calculated for the growing period, when they may influence crop growth, rather than averaged over the whole year.

Do you understand now how important it’s to choose a suitable zone?

Division of Tanzania into Agroecological zones

Now back to our homeland. The research done by Mlingano Agricultural Research Institute (ARI Mlingano) divided Tanzania into seven Agroecological zones. Which are;

The central zone covers the central regions of Tanzania; Dodoma and Singida.
The eastern zone covers Morogoro, Dar es Salaam, Tanga, the Coastal region, Unguja and Pemba islands.
Western zone: covers Kigoma and Tabora regions.
Lake zone: includes Mara, Shinyanga, Mwanza and Kagera
The northern zone covers Arusha and Kilimanjaro regions
The southern zone has two regions: Lindi and Mtwara
Southern highlands zone which includes Mbeya, Iringa, Njombe, Ruvuma, and Rukwa regions.

Due to changes in regional administrative boundaries, some regions were not present during the construction of the Agroecological map above. And probably you would need to know the Agroecological zone of your area, don’t worry just go to district soil, agroecological zone or crop suitability map and select your district and you should find even the crops that grow better in your district.

Keep in mind;

“The performance of the crops depend on the agro-ecological zone, and that, not all crops can perform better in all agro-ecological zones. So you must choose carefully either the crops to cultivate in your agro-ecological zone or the agro-ecological zone for the crops you want to produce.”

I hope that helps you.

This article was prepared by Mtalula Mohamed, the then final-year student at Sokoine University of Agriculture (2016).

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