436 SOUTHERN FIELD CROPS 



No one formula is best for all soils. The following is only 

 suggestive for soils needing a complete fertilizer under conditions 

 where moderate fertiUzation is desired : — 



150 pounds per acre of high grade sulfate or of muriate of 



potash, 

 250 pounds acid phosphate, 

 150 pounds nitrate of soda (or 320 pounds of cotton-seed meal 



or -tankage). 



Potash salts, acid phosphate, and cotton-seed meal or tankage 

 are applied before bedding the land, while nitrate of soda is 

 drilled alongside of each row soon after the slips have rooted and 

 begun to grow. 



Farmers in the cotton states are sometimes afraid to use 

 stable manure or other nitrogenous fertilizers, lest the crop" run 

 chiefly to vines. ' ' When the fertilizer is properly balanced, — that 

 is, made up of the proper proportion of nitrogen, phosphoric acid, 

 and potash, — there is little, if any, danger that the growth of vines 

 will be excessive. Only by the development of a large growth of 

 vines can a maximum crop of roots be secured; for the starch 

 and other valuable material, of which the roots largely consist, 

 can be manufactured only by an abundance of leaves and other 

 green portions of the plant. 



In the parts of New Jersey where this crop is extensively 

 grown for market and large yields are secured, it is not unusual 

 for a farmer to apply 10 tons of manure per acre for sweet-pota- 

 toes, in addition to 500 to 1000 pounds of commercial fertilizer. 



407. Place in the rotation. — Since a field of sweet- 

 potatoes needs to be kept free from grass and weeds at 

 the least expense, it is generally advisable for this crop 

 to follow one which leaves the land clean; that is, relatively 

 free from seeds of weeds and grass. One of the best of 

 such crops to precede sweet-potatoes is cotton. 



It is also advantageous that the preceding crop supply 

 a large amount of humus. Cowpeas or velvet beans 



