1914. 



PUBLIC DOCUMENT — No. 31. 



35 a 



On the south corn acre manure alone at the rate of C cords 

 per acre gives about COO pounds more hay than the combination 

 of 4 cords of manure and 160 pounds of high-grade sulfate of 

 potash. This is the twenty-fourth year of this experiment. 



In the experiment comparing different phosphates used in 

 such quantities as to furnish equal phosphoric acid, which has 

 been in progress since 1897, the crop this year was corn. The 

 apparent effects of the different phosphates upon the crop are 

 shown in the following table : — 



Gain or Loss. 



Plot 1, no phosphate, 



Plot 2, Arkansas rock phosphate, 



Plot 3, South Carolina rock phosphate. 



Plot 4, Florida soft phosphate. 



Plot 5, basic slag meal. 



Plot 6, Tennessee rock phosphate, . 



Plot 7, no phosphate, 



Plot 8, dissolved boneblack, 



Plot 9, raw bone, .... 



Plot 10, dissolved bone meal, 



Plot 11, steamed bone. 



Plot 12, acid phosphate. 



Plot 13, no phosphate. 



It will be noted that the effect of the untreated rock phos- 

 phates upon the yield of grain is extremely small, there being 

 in most cases a slight decrease. On the other hand, the bone 

 meal, both raw and steamed, the basic slag and the superphos- 

 phates (dissolved boneblack, dissolved bone meal and acid phos- 

 phate) all give moderate increases. There is an increase in 

 stover in all cases, but materially smaller on the untreated rock 

 phosphates than on most of the others. 



The crop of grain was undoubtedly smaller than it otherwise 

 would have been because of the effects of the heavy frost which 

 came just before the middle of September, at which time the 

 ears were not mature. This frost killed the leaves of the plants 



