THE POTATO. 133 



should receive only a light phosphatic dressing without the 

 kraal manure, or the crop of cowpeas might be eliminated in 

 the rotation or used for hay. 



(2) Under Irrigation — two-year rotation. 



1st year — Winter crop : wheat with a dressing of 



phosphates. 



Summer crop : cowpeas ploughed under. 

 2nd year — Winter crop : wheat, with a dressing of 



phosphates. 



Summer crop : potatoes with kraal 



manure. 



(3) Seven to nine years' rotation : lucerne, followed by 

 potatoes, followed by wheat, having a dressing of phosphates; 

 land then to be re-sown to lucerne. 



Planting. — Under irrigation, two crops are grown in one 

 year, the spring-planted crop for the summer and autumn ; and 

 the summer-planted crop for the winter and spring markets. 



The early crop is planted from June to September accord- 

 ing to the climatic conditions of the locality ; in the Low Veld, 

 where litle frost is experienced, the crop is planted in June 

 and July; in the High Veld and Middle Veld in August, or 

 as soon as the danger of late frosts is over. 



For the summer crop, planting takes place in December 

 and January. 



Without irrigation the date of planting will vary with the 

 commencement of the seasonal rains for the locality and the 

 condition of the stored seed tubers, usually from September 

 to January. 



For the spring planting the early varieties are used, 

 and medium and late varieties for the main crop. 



The tendency in South Africa is to plant much too closely. 

 The rows should be three to three and one-half feet apart, and 

 the tubers 12 to 18 inches in the rows. In moist climates, or 

 under irrigation, on rich soils, a much closer spacing is used. 



The tubers should be planted four to six inches below the 

 surface, depending on the nature of the soil. 



Planting machines, under South African conditions of 

 labour, have not proved satisfactory, and the crop is mostly 

 put in by hand. 



After Cultivation.— Before the plants appear above 

 ground, it is often necessary and advisable to harrow the 

 field to destroy weed growth and to break any crusts which 



