122 Journal or the Department of Agricultuke. — Aug., 1922. 



its sustenance, but in its absence the rainfall runs off easily, its 

 efficiency is diminished, and the soil is eroded. The congregating of 

 stock, as practised at present, leads to much destruction of the vegeta- 

 tion by trampling and overgrazing. A characteristic of areas of low 

 or intermittent rainfall is the high proportion of perennials in its 

 vegetation, a provision of nature in that having established a well- 

 developed root system they are able to make the fullest use of the 

 rain when it comes, and are in vigorous growth before the annuals 

 have had time to germinate. Perennials under natural conditions are 

 thus able to thrive with a scanty rainfall and also to repress and 

 mask the existence of the annuals. Destroy the perennials and the 

 annuals will have all the rainfall and become increasingly prominent, 

 but will more readily die, for, unlike the former which are able to 

 go into a resting condition between rains, annuals need a sufficiently 

 moist soil to make growth continuous. Veld composed of annuals, 

 therefore, is less certain of being able to carry its quota of stock 

 throughout the year. Yet on an overgrazed veld perennials, which 

 spring into edible growth first, are eaten down before they are able 

 to manufacture their full reserve food requirements, and if this 

 process is continued the plant dies. Palatability also plays its part, 

 so that the perennials the animal most likes are first eaten, and gradu- 

 ally they disappear from the veld until in overgrazed parts the sur- 

 viving plants are those of an undesirable and uncertain type. 



Overgrazing is most detrimental to the veld when growth is most 

 active, for instance after a drought breaks, for this rapid growth after 

 plenteous rain determines, not only how much fodder there will be 

 for the coming dry period, but also the amount of storage of rootstock, 

 bud and seed, and through this the yield of fodder in the coming year. 

 Thorough grazing subsequent to this period is not so exhaustive; 

 investigations in America show that by reducing the number of stock 

 during the main grazing season (which is not possible on the over- 

 stocked, unpaddocked farm) to about half the average number the 

 range can carry for the year, thereafter grazing fully for the remain- 

 der of the year (eight months), the range so treated improved as much 

 as similar ranges protected for the whole year. So with the valuable 

 Karroo fodder plant, the " skaap bos," it is evident that resting is 

 necessary, and that nothing is more harmful than overgrazing at its 

 period of active growth. 



When a farm is divided into camps and the grazing can be regu- 

 lated, the animals will be compelled to eat all the veld growths, not- 

 withstanding their degree of palatability, that are not harmful, so 

 that all useful plants get an equal chance when the camp, in the 

 course of rotation, is rested. Where this is not practised, the stock 

 naturally confine their choice to the most palatable shrubs, leading to 

 their destruction and the spread of the less palatable ones. 



The chief causes, therefore, of the daily deterioration of the veld 

 are kraaling, scarcity of suitable watering places, and overgrazing. 

 And this deterioration in itself induces accelerated speed in its career 

 of damage by resulting in the ever-growing need for greater move- 

 ment of stock to find food and water, leading to overgrazing and the 

 mechanical destruction of the veld, first the palatable perennial and 

 finally the remaining herbage. Then comes the culminating evil — 

 the diminishing efficiency of the rainfall. As the vegetal covering 

 becomes scanty, so is the run-off of the rainfall accelerated, and lei5s 



