The condition and productivity of your rangeland is the foundation on which a productive and viable livestock production enterprise in Namibia should be built. Two of the most important elements of rangeland production and restoration are OVERGRAZING and OVERSTOCKING. These two elements of rangeland management are extremely important but are very often confused with each other.

 

Overgrazing takes place in the growing season when a camp is not rested long enough after a grazing period that allows enough time for perennial grasses to recover. If overgrazing takes place for too long, the root system of the grass will reduce, and with it the ability to store growth reserves, until it is so small that the perennial grass plant cannot survive a normal dry season or drought period. The end result of overgrazing is that the perennial grass plant dies.

 

Overstocking on the other hand happens during the dormant season where more animals are kept than what the available fodder sources allow for. The end result of overstocking is that animals don’t perform optimally and even die due to fodder shortages. These two elements have actually very little to do with each other and overgrazing is even possible while under-stocked.
Since this is the end of the growing season and the start of a long dry season, this article will focus on preventing overstocking, or on the positive side, ensuring that there is enough fodder available to livestock until it rains again. A second article addressing how to prevent overgrazing will follow towards the beginning of the next growing season.

 

How to address overstocking
The 2016/17 rainfall year was generally much better than the previous season, although in some areas farmers are still in danger of experiencing major fodder shortages during the ensuing dry season.

 

Mrs Freya Lundt from the farm Kamambonde Ost in the Omaruru district has arguably the best records for a private farmer on seasonal variation in fodder availability based on the clipping of quadrats in Namibia. Figure 2 clearly illustrates the variation in fodder availability at the start of the dry season between different years from 2000/1 to 2014/15. These data also clearly confirm that carrying capacity and stocking rate are not fixed and will vary from year to year, depending on the rainfall.
This is again the time of the year that each livestock farmer should be asking the following important questions:

 

  • How much fodder do I have available on my farm?
  • What are the current fodder requirements of my livestock herd?
  • How long will the current available fodder last?

 

In order to answer the first important question (how much fodder do I have?), several techniques and possibilities exist. The first one is to physically go and cut a number of representative quadrats evenly distributed over the farm, dry the grass for 14 days and weigh it. This is currently still the most reliable method, but unfortunately very labour intensive and in our experience, few farmers find the time to do this. 

 

A second possibility is to use a reference photo-guide of different fodder availability scenarios and, by relating a specific piece of land to a specific photo, fodder availability can be estimated. Agra ProVision and Agri-Ecological Services are in the process of developing photo guides for a number of areas in the country. 

 

The third possibility, which is currently still being tested, is to directly read it from an herbaceous production (kg Dry Matter/ha) map that is generated at the end of the growing season from calibrated satellite derived data.  These satellite products are currently tested with several farmers and also in two communal grazing systems. So far the results are promising and further validation is under way.
It does not matter which method you use, as long as you can produce a reliable estimate of fodder availability. 

 

In terms of the second and third questions, a stocking rate calculator (SRC) has been developed.  
This tool intends to assist land users (livestock and game) to plan their dry season fodder flow.
The scenario on the left indicates that, with the current livestock and game numbers on the farm, available fodder will last until end of February 2018, while in the scenario on the right it will only last until the end of September 2017. 

 

This information is crucial to the farmer because in the first case animals will have enough to eat until it rains again, while in the second case, the herd will experience fodder shortages 6 months into the dry season, with at least 3 months to go before the next rainy season is likely to start. This can mean a difference between a “normal” season and a “drought’, which could have been avoided. 
The calculator still requires further fine-tuning, for example how the percent fodder that can really be used by animals differ between regions. 

Several factors, including trampling by animals, termites and so on, determine that only a fraction of the initially available biomass should be considered if planning fodder flows. Another area that requires further research is how the browse percentage differs between herbivore species and regions. For example, cattle in the broad leaf savannas are known to browse substantially, but how much is still debated. In the SRC both the utilization factor and browse: graze ratio can be adjusted, although some default values are suggested.     

 

Conclusion
Even if the rangeland situation this year is much better than last year, it is still important that each farmer determine if there is enough fodder available for the current livestock herd on the farm. Remember this available fodder should last for at least 9 months until the next “full” grass bite will be possible. This time of the year is the right time to estimate fodder availability and several methods exist or are currently being developed to do so. Using a stocking rate calculator will determine how long the available fodder will last with the current livestock herd on the farm and allow the farmer to take timely action if necessary.

Contact AGRA

Pauline Lindeque (DR)Email Me
Position: Manager: ProVisionTown: Windhoek
Tel.: +264 61 290 9378Fax.: +264 61 290 9345Cell.: +264 (0) 81 127 2978

A Project of

European Union

Implementing Partners

ProVision Agri Ecological Services

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