198 Journal of the Department op Agriculture. 



affords valuable and up-to-date information on the subject. The 

 greater part of the article, including the whole of the information 

 on the practical methods of cultivation of the buchu plant, has been 

 written by the Curator of the National Botanic Gardens, while certain 

 other details have been added by the Director, who will be pleased 

 to assist growers with further information arising out of the experi- 

 ments at Kirstenbosch. 



The Sweet Potato: Its Extended Use. 



At present the sweet potato is used in South Africa solely as a 

 human and stock food, and the area under the crop suffices to meet 

 the demand. But given a wider use for the tuber, there are areas of 

 land suitable for its production which could meet a demand far in 

 excess of the present one. In view, therefore, of the shortage and 

 high cost of petrol, Dr. Juritz, the Agricultural Research Chemist, 

 draws attention to the possibilities of utilizing the sweet potato in 

 the production of alcohol on a large scale in order to serve as a basis 

 for liquid fuel. A cheap, industrial alcohol is needed, and Dr. Juritz, 

 who has considered the possibilities of the prickly pear fruit and the 

 sugar beet, is of opinion that in South Africa the sweet potato 

 probably offers the best facilities for producing a raw material for 

 the purpose. Particularly there is an extended belt of country 

 between Riversdale and Humansdorp, an outside limit of nearly 200 

 miles, available for sweet potato culture and in view of the possibi- 

 lities facing it. Dr. Juritz has prepared a valuable article, the first 

 part of which we publish elsewhere in this issue, on the sweet potato 

 and its cultivation, which will prove of great benefit to growers. In 

 supplying the law material for the manufacture of a cheap, industrial 

 alcohol, the cost of production is a most important item; in the 

 eastern sweet potato section of the United States the cost of produc- 

 tion is given at £16. 10s. 2d. per acre (not including the cost of 

 hauling to market), while in many sections of the southern States 

 the corresponding cost would not exceed £8 per acre. Against this 

 the produce of an acre has often realized as much as from £20 to 

 £30. From information obtained from the largest grower of sweet 

 potatoes in the Union, it is found that it costs him approximately 

 £6. 12s. per acre, excluding costs of bags and cartage, cuttings, and 

 manure. This farmer has obtained a yield as high as 16,000 lb. per 

 acre, but the average Union yield, according to the 1918 Census is 

 3390 lb. For various reasons the latter figure is considered unduly 

 low. Taking individual districts, we find that the average in Oudts- 

 hoorn was 7632 lb. per acre, while others produced an average rang- 

 ing from 4600 to 5700 lb. The average in the United States is 

 approximately 5340 lb. per acre. 



The sweet potato is already used in other countries for the produc- 

 tion of alcohol, and Germany offers a striking example of what can 

 be done in this respect with the common or Irish potato and the ways 

 in which agriculture benefited as a result. Dr. Juritz refers to this 

 in his article. Altogether the author opens up a wide field of 

 enterprise and his observations and advice, largely based on the 

 information gleaned from a practical grower in the George district, 

 will enable the farmer to acquaint himself w^ith the economic and 

 cultural aspects of the subject, preparing him to cope Avith such 

 increasing demands for his product as may follow activity in the 

 local manufacture of industrial alcohol. 



