Online Reporter
Engineer Edwin Zimunga
| Z |
IMBABWE recently commemorated International Soil Day, which ran under the theme “Caring for Soils: Measure, Monitor, Manage”. This theme emphasises the vital role of soil health in ensuring sustainable agriculture, food security and climate resilience — pillars of Zimbabwe’s economy and national development.
Zimbabwe is one of the signatories to the United Nations Charter and a member of the United Nations Food Agriculture Organisation (FAO). On December 5 every year, we globally celebrate International Soil Day. This is in recognition of the soils’ diversity, sustainability and importance in human and wildlife development.
Commemorations
This year’s commemorations left no place and no one behind as they took place at the village, ward, district, provincial and national levels. We brought on board children from schools under the Ministry of Primary and Secondary Education to take part in competitions, recite poems and be involved in other activities that speak to the celebration of the soil.
International organisations like FAO and the United Nations Development Programme, farmers and several Government ministries were part of the celebrations.
Ensuring soil health and fertility
In 2021, the Government saw it fit to revisit the whole issue involving the well-being of soils. You do not grow plants in the air. You do not grow plants in the sky. You grow them on the soil. That means the source of food security in the country is the soil.
In view of this, we had to set up the Soil Engineering and Conservation Department at the Ministry of Lands, Agriculture, Fisheries, Water and Rural Development.
The department oversees a lot of work that has to do with the soil. Terracing, for example, is scientific programming around soil management. When you go to mountainous areas where you cannot just grow crops ordinarily like you do on flatland, we have the terracing programme, where we do a lot of construction of fields.
In one area, you can grow crops and do some forestry after engaging in terrace construction. Be it bench terracing or contour terracing, it all has to do with engineering and scientific principles where we look at the mechanics of the soil within a particular area. We then design it in such a way that we avoid soil erosion and nutrient loss. For the ordinary farmer, there is the age-old practice of contour farming. It is a traditional method where the fields are marked based on the natural contour lines of the area.
It is a key tenet regarding soil management that we follow as a country and as a ministry.
We are also looking at things like windbreaks, where we are encouraging the planting of trees and high-rise crops to avoid wind erosion. This also avoids a lot of surface runoff, where these windbreaks apply, especially in areas with open valleys.
We also build what we call check dams and gabions around lands that are usually very susceptible to erosion and degradation.
In most cases where you see a lot of wires, where stones are put in there together with the planting of Latvia grass or other plants, this has to do with the management of river beds, among other things.
We also do what we call field drainage designs. There are fields that naturally either clog with water or that naturally wash away the topsoil. What we then have to introduce is an important soil engineering component called drainage or field drainage design.
Field drainage designs are done using well-calculated engineering computations, where engineers go and study the essence of the mechanics of the soil, the prevalence of rains and wind, which are agents of erosion, as well as losses of nutrients that can happen.
We have introduced another concept where we look at issues to do with geotextiles and erosion controls.
Soil conservation through Pfumvudza
The Pfumvudza/Intwasa programme is a conservation agriculture method. It is primarily meant to conserve soil. It has become the flagship of our climate-proofing efforts in agriculture.
It is marked by reduced cultivation, combined with mulching and other techniques.
We also have grassed waterways. You see a lot of grass in those waterways. Why are they grassed? The grass is there to compact the soil. If we do not do this, you will see a lot of erosion.
We also ensure soil fertility through crop rotation and planting of cover crops. This is another good method of soil conservation.
Also, we do rainwater harvesting and storage. This is when we look at the national programme for the construction of weirs and small earth dams. These are designed to trap sediment, especially along waterways. Why? Because we do not want our large dams to silt.
Engineer Edwin Zimunga is the chief director for engineering, mechanisation, post-harvest agro-processing and soil conservation in the Ministry of Lands, Agriculture, Fisheries, Water and Rural Development. He was speaking to The Sunday Mail’s Theseus Shambare.
The source of silt now becomes a small weir, which we can then desilt with just a little bit of engineering work, which is cheaper.
We use the sand for house construction, for example, rather than have our major water sources silting.
This does not only cover fields, but it also covers paddocks and overgrazing. All these other things are done for the sake of our livestock and wildlife.
That is why you also find that there is this huge collaborative effort with the Ministry of Environment; it is because we house the engineers who do the scientific work and they house the conservation discipline for wildlife.
That is how we then work together under the Whole-of-Government approach.
Policies and regulations
In 2022, we embarked on a journey where we started working on the national soil conservation policy. We did a lot of consultations and suffice it to say our population out there is seeing the importance of soil conservation.
That process culminated in the creation of a draft that will be tabled before Cabinet to make sure that this becomes a national policy on how we manage our soils in everyday life for everyday food security.
Engineer Edwin Zimunga is the chief director for engineering, mechanisation, post-harvest agro-processing and soil conservation in the Ministry of Lands, Agriculture, Fisheries, Water and Rural Development. He was speaking to The Sunday Mail’s Theseus Shambare.
