Mhlupheki Dube 

CLIMATE change has altered two aspects about our rainfall pattern namely the distribution and the amount. 

The country is experiencing low amount of rainfall that is not evenly distributed. Only a few instances do we get flash floods due to high intensity of rainfall received over a very short period of time. 

Hwange for example experienced flash floods last week after recording around 139mm of rainfall in a very short period of time. 

The other aspect of climate change is the general increases in atmospheric temperatures and this means the little precipitation that is received is quickly lost through evapotranspiration. 

Naturally these changes have a bearing on the carrying capacity of your farm and this is what we seek to deliberate on this week. 

As a starting point it is important to impress up on farmers that the carrying capacity of your farm is not static, it changes over time as certain factors change. 

The farmer therefore needs to be on the lookout for changes on his farm and interpret them as to how they relate to the carrying capacity of his or her farm. 

The first important aspect I want to look at regarding the carrying capacity of your farm is the livestock drinking water. 

Most practitioners when they talk about farm carrying capacity, they overlook the important role water has on the carrying capacity. 

You will not be able to carry even one livestock unit in your farm if there is no access to drinking water. Now due to the general decrease in the amount of rainfall being received as a result of climate change water bodies in the farms are depleted. 

Right now, we have some farms whose rivers have not been able to flow not even once and consequently the dams have not recorded any inflows. 

This means that even if you received some precipitation which allowed your grass to germinate and grow albeit not to its full potential, the grass will not be your limiting factor but drinking water will be.  While you may be able to buy commercial feed and hay, you are unlikely going to buy drinking water! 

So your farm carrying capacity this year will drop tremendously because of unavailability of drinking water for your animals. 

The second determinant to your farm carrying capacity is the proportion of your woody species to the grass species.

 If you want to increase your farm carrying capacity you have to decrease the woody vegetation and increase the grass component of your veld. 

Cattle are predominantly grazers which means most of its feed intake is through grazing not browsing and hence increasing trees against the grass only decreases what your cattle can eat. 

Again, farms that have dense woody vegetation tend to have very little undergrowth which is your grasses due to shading and poor sunlight penetration. 

If you want more grass, reduce the  number of trees in your farms and open up some areas for the grass to grow freely especially in this era of poor rainfall.

The Zimbabwe Forestry Commission is not going to like this, however, it is a fact. The third aspect which has a bearing on the farm carrying capacity is the quality of grasses that dominate your veld. 

Grasses can be broadly classified into palatable and non-palatable ones as it relates to voluntary feed intake by the animal. 

The less palatable grasses are those ones which your cattle will only graze because they have finished all the other grasses and there is nothing else left in the veld. In other words, your animals had no choice anymore. Unfortunately, these are also the type of grasses that tend to be prolific growers and they suppress the growth of the palatable grass species. 

The palatable grass is the one which your animal likes and will finish it first. 

These also happen to be less prolific in terms of growth. This means if you do not take notice of the type of grass on your farm and control the less palatable grass species, they will completely replace the palatable ones and in no time your farm will have grasses which your animals are not willing to graze on. 

Technically this reduces your carrying capacity because you have grasses which your animals are not willing to graze and it compromises the condition of your animals. It then becomes important for farmers to deliberately manage the veld in such a way that you don’t lose your palatable grasses. 

This means avoid overgrazing your veld especially where you have the palatable grasses because it will be difficult for that grass to regenerate. 

Introduce new palatable grasses that have prolific growth so that your veld has more palatable species. 

The seed for such grasses are now found in some seed houses in the country as well as research stations such as Matopos Research. You can also use high stocking densities in parts of the veld with a lot of unpalatable grasses so that animals can graze that grass to the ground, trample it and allow for growth of more palatable species in subsequent seasons. 

It is important to note that your farm carrying capacity changes as conditions change and hence your management needs to respond to the changes appropriately. 

Uyabonga umntakaMaKhumalo. 

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