9 



Increase of seed cotton per acre when acid phosphate 

 was added : 



To unfertilized plot 320 lbs. 336 lbs. 



To cotton seed meal plot .126 lbs. 550 lbs. 



To kainit plot 233 lbs. 263 lbs. 



To cotton seed meal and kainit 



plot -.233 lbs. 263 Ibs.^ 



Average increase with acid phos- 

 phate 219 lbs. 378 lbs. 



Increase of seed cotton per acre Avhen kainit was 

 added : 



To unfertilized plot 205 lbs. 107 lbs. 



To cotton seed meal plot 79 lbs. 337 lbs. 



To acid phosphate plot 84 lbs. • 132 lbs. 



To cotton seed meal and acid phos- 

 phate plot 86 lbs. • 50 lbs. 



Average increase with kainit 116 lbs. 157 lbs 



The principal need of this soil, clearly shown in each 

 of three tests, is for phosphate, which has paid a large 

 profit, whether employed alone or in combination with 

 any of the other materials. The increase attributable 

 to phosphate in each of the three years is respectively 

 464, 219, and 378 pounds of seed cotton per acre. Cot- 

 ton seed meal usually increased the yield more than 

 enough to cover its cost, the averages for the 3 years 

 being respectively 152, 130, and 144 pounds of seed cot- 

 ton. Its relatively slight effect suggests the advisabili- 

 ty of reducing the amount of cotton seed meal, of which 

 about half as much as of phosphate might be used for 

 cotton. 



Kainit was the least beneficial on this soil of the in- 

 f^redients of the complete fertilizer and the figures indi- 

 cate that its addition to the jiiixture of phosphate and 

 kainit was not profitable. 



