334 



SOUTHERN FIELD CROPS 



reduces the amount of water necessary to keep the plant in health, 

 judging by the fact that potash has been found to reduce the 

 amount of water transpired by the leaves of the corn plant. 

 Potash in the fertilizer usually causes the later retension in the 

 autumn of the leaves of the cotton plant (Fig. 148). 



Fig. 148. — A Cotton Field, showing the Effects of Potash in 

 Retention of the Leaves. 



On the right, the fertilizer contained no available potash ; on the 

 left, it contained 50 pounds muriate of potash per acre. 



308. Kainit, muriate and sulfate of potash. — In ex- 

 periments in Alabama, a pound of potash in the form of 

 muriate was as effective in checking rust as when an equal 

 amount was applied in the form of kainit.- It is slightly 

 less convenient to apply muriate of potash ; for as this is 

 four times as strong as kainit, it is advisable to use only 



