WHEAT. 251 



then receive liberal irrigation. Irrigation after the grain has 

 been well filled is of no use, as the roots cease functioning 

 about three weeks before the crop is mature. Experimental 

 work in various parts of the world, and observations in South 

 Africa, show the tendency in practice to over-imgate. The 

 necessity for irrigation is shown when the plants present a 

 flaccid and yellowish appearance, the tips of the leaves turn- 

 ing brown. 



Rotations. — As in most crops in the Union insufficient 

 attention has been paid to this important aspect. As wheat 

 may be classed as a delicate feeding crop, and, therefore, 

 requires readily available plant-food, where practicable, a cul- 

 tivated crop should intervene between a green-manuring crop 

 and the planting of wheat. 



The effect of previous crops on wheat is well shown in the 

 following result obtained from experiments conducted at 

 Potchefstroom Experimental Farm — viz. :— 



1916. 1917. 1918. 



Pounds. Pounds. Pounds. 



Velvet beans cut for fodder, wheat 



following 1,240 1,080 1,040 



Cowpeas cut for fodder, wheat fol- 

 lowing 1,400 1,380 1.240 



Maize summer crop, wheat winter 



Crop 800 520 540 



Sunflower summer crop, wheat 



winter crop 400 600 600 



No fertiliser was used in the above experiment. 



The value of the legume, even when used for fodder, is 

 clearly demonstrated. Whenever possible legumes such as 

 cowpeas should be grown on wheat-lands in preference to such 

 crops as maize, sorghums or sunflower. 



The following rotations are suggested, but, of course, 

 should be altered to suit the conditions of the locality and the 

 requirements of the individual farmer. 



(!) 1st Year — Winter crop — wheat. 



Summer crop — cowpeas ploughed under. 

 2nd Year — Winter crop — wheat fertihsed with phosphates. 

 Summer cro}) — potatoes or mangels. 

 (2) On the Highveld of the Eastern Transvaal, when suit- 

 able, early varieties are used, the following rotation 

 might be successful : — 



