520 THE FARMERS' HANDBOOK. 



THE SWEET POTATO.* 



The sweet potato is not cultivated in this State as it deserves to be, or as 

 extensively as our climatic conditions will allow. At present its cultivation 

 as confined almost to the thin fringe oi coastal area, but its range of suita- 

 bility has by no means been determined; in fact, its determination has 

 hardly been commenced. If proper care be taken with regard to the raising 

 of the " plants," and the selection of varieties, many districts hitherto 

 regarded as totally unsuitable will be found to suit this crop. Sweet pota- 

 toes have been successfully grown at Queanbeyan and Howlong, and in a 

 few isolated parts of the dry west where water is available. Generally 

 speaking, better results may be expected in the warmer districts on the 

 coast or inland than on the cool tablelands. 



At Hawkesbury Agricultural College the crop has proved a splendid 

 drought-resister. If a little attention be devoted to keeping down weeds 

 r.nd conserving moisture by hoeing — hand or horse — it is surprising how 

 much dry weather the sweet potato will resist; and as for heat, some of the 

 varieties simply revel in it. 



Soil Required. 



The ideal soil for this crop is a sandy one, well supplied with organic 

 matter. In a soil of this character, the plants possess almost all the hardiness 

 of weeds, and the roots develop well, being even in quality and of good 

 shape. Light loams are also very suitable; but the more clayey a soil is, 

 the more unsuitable it is. In poor sandy soil, 4, 5, and 6 tons per acre are 

 obtained with but little trouble. 



Preparation of the Soil. 



Usually two ploughings are considered necessary to prepare the soil for 

 this crop. The first is done during the winter or early spring but sufficiently 

 early to allow the soil to settle and become compact before planting. It will 

 then be in a suitable condition for the young plants to utilise the moisture 

 in the subsoil should it be required. This first ploughing can be as deep as 

 the soil will admit without bringing the sour subsoil to the surface. The 

 second ploughing, on soils at all light, should be only shallow — say, about 

 4 inches. Unless this precaution be taken the roots in sandy soils are apt 

 to become excessively long and thin, rather than chunky, which latter 

 characteristic is to be desired. Some varieties, notably Pierson, are not as 

 bad in this respect as others. 



Manuring. 



If the roots are intended to be used as a vegetable, the direct application 

 of farmyard manure to this crop is not recommended. Whilst stable manure 

 improves the yield both of vine and roots, it is at the expense of quality in 

 the latter. 



If plenty of farmyard manure be available, it is a good plan to apply it to 

 the crop preceding the sweet potatoes. 



The practice at the College, attended with excellent results, is to main- 

 tain the supply of organic matter in the soil by the system of cropping 

 adopted, and to use the following mixture of fertiliser: — 



Superphosphate . . . . . . 4 parts. 



Sulphate of potash . . . . . . 1 part. 



This is applied at the rate of ?> rwt. ppv ncr^ in th^ drill whop the plant? 

 are set out. In cool districts it is likely that the application of 25 to 50 lb. 

 of nitrate of soda in addition to the above mixture will be found beneficial. 



A. J. Firm, Inspector of Agriculture. 



