Last update: March 30, 2012 09:55:43 AM E-mail Print


Use - don't abuse karoo veld

F Hobson 


In order to utilise veld optimally without damaging it over the long term, farmers have three management tools at their disposal, says Mr Felix Hobson of the Grootfontein College of Agriculture.

He told delegates of the Grassland Society Congress, held at Grootfontein, that both research and experience confirm that the basics of sound veld use are correct stocking rates, appropriate rotational grazing and the diversification of stock. Used properly, these management tactics should go a long way to optimise production, while at the same time conserving veld, he said.

Mr Hobson made it clear that the most far-reaching strategy is to match stock numbers with grazing capacity. It is therefore regrettable, he said, that, according to estimates, the Karoo is at present overstocked by about 30%.

Mr Hobson stressed that it was foolhardy to apply excessively high stocking rates to achieve higher production per hectare, since it would ultimately lead to the total destruction of the veld.

He conceded that it is practically impossible to determine actual grazing capacities of the veld. He, in fact, mentioned that actual grazing capacity has been labelled by a well-known pasture researcher as a theoretical abstraction. In view of this problem, he urged farmers at least to make use of estimated grazing capacities as a guideline. Although it appears that fairly satisfactory subjective carrying capacity assessments can be made by experienced persons in terms of nutritional supply of the veld, the search for an accurate objective method of assessment continues.

To deal with the problem of a continually fluctuating carrying capacity, Mr Hobson offered, as the most feasible solution, the strategic withdrawal of excess numbers of stock to either feeding kraals, irrigated pastures or to especially established drought fodder reserves.

Other alternatives which he mentioned were the maintaining of the stocking rate at approximately 50% of the long-term grazing capacity, leaving a buffer of fodder reserves for poor years, and the reduction of the percentage of breeding stock in the flock so that adjustments can be made by selling off or buying in non-breeding stock.

Research in the Karoo has indisputably shown that rotational grazing at economical stocking rates is far superior over the long term to continuous grazing as far as ,veld condition and animal production is C9ncerned. Furthermore, rotation reduces selective grazing.

Mr Hobson, in fact, added that, through strategic rotation of stock, the botanical composition of the veld can be manipulated. By way of example, he explained that repeated winter grazing and summer rests can be applied to suppress undesirable bushes and to promote perennial summer grasses. Similarly, a pure grass stand can be converted into pure Karoo-bush veld by the application of recurrent summer grazing and winter rest.

He pointed out that grazing of the same veld in the same season in successive years is, however, very detrimental to the vigour and survival of certain Karoo plants.

According to Mr Hobson, rotational grazing in the Karoo varies from slow elementary systems with a few camps to fast sophisticated multicamp rotations. However, he advocated the group camp approach as being suitable to any farm or area in the Karoo.

This approach consists of dividing the grazing camps into several groups, and resting these systematically. Within the group scheduled for grazing, any utilisation strategy, such as the beneficial properties of non-selective grazing and short duration grazing, controlled selective grazing and special seasonal grazing treatments, can be applied.

It is generally accepted that the condition of mixed veld is enhanced when grazed by a variety of animal species and types. Karoo veld is no exception in this respect, Mr Hobson said.

An approximate 35% dietary overlap exists between large and small stock, while the dietary overlap between the various small stock breeds is about 55%. It therefore stands to reason that higher stocking rates can be applied with multi-species grazing.

Farmers are, however, largely deterred from this practice, owing to the attendant management complications, as well as such factors as higher capital outlay for physical facilities, relative profitability between stock breeds and traditional stock preferences.




Karoo Regional Newsletter Autumn 1983