No. 6. 



DEPARTMENT OF AGRICULTURE. 



859 



uaturalh' in the soil, that it would be necessary to imitate nature's 

 methods and till the soil with organic matter. Then, again, could 

 not the phosphoric acid contained in the mineral phosphates be 

 rendered available in the soil through the agency of organic matter 

 if these phosphates were applied in their natural state, except 

 being pulverized? If these (juestions be answered in the aflfirmative, 

 and the farmer can arrive at an economical and satisfactory method 

 of providing the requisite amount of organic matter in the soil, 

 then it will be possible to avail of the phosphates already in the 

 soil, and thus, on some lands, make it unnecessary to purchase 

 phosphoric acid. When recourse to purchase becomes necessary, 

 then a cheaper form of phosphoric acid can be used and do away with 

 paying out so much money for dissolved or acid treated phosphates, 

 which, in the end, is practically a means of accomplishing or arriv- 

 ing at a mechanical condition. 



These are the ideas that call for the planning and management of 

 the experiments outlined in the following program: 



TABLE IS. 

 Phosphoric Acid Experiments. 

 (Plots One-Tenth of an Acre Each.) 



S 



Kind of Fertilizer and Treatment. 



o 



p. 



a 



C 



1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 

 14 

 IB 

 16 



17 



18 

 19 

 20 

 21 

 22 



CRIMSON CLOVER SEEDED IN CORN. 



Double super-phosphates (Soluble P2 O.-,) 



Dissolved bone black (Soluble P. O5), 



Dissolved South Carolina rock (Soluble P2 Osl 



Double super-phosphates (Pj O5) 



Nothing, 



Iron alumina phosphate (Reverted P2 Os) 



Bone black (Insoluble P2 O5), 



Raw bone meal (Insoluble Pj O5), 



Slag phosphate (Insoluble P2 O5), 



Nothing 



Ground South Carolina rock (Insoluble P2 O5) 



Florida soft phosphate (Insoluble P2 O5), 



CORN GROUND LEFT BARE DURING WINTER, NO GREEN 

 CROP TURNED UNDER. 



Same as No. 8. 



Same as No. 9 



Nothing, 



Same as No. 11, 



Same as No. 12 



RYE SEEDED ON CORN 



Same as No. 8 



Same as No. 9, 



Nothing 



Same as No. 11 



Same as No. 12 



GROUND. 



32 

 73V6 

 100 

 37 



37 

 Bl'/4 

 66% 

 92 



53 

 56 



66% 

 92 



53 



56 



66% 

 82 



5S 

 56 



319 



735 



1,000 



370 



370 

 514 

 667 

 920 



560 

 560 



667 

 920 



530 

 560 



667 

 920 



530 

 560 



•These quantities give each plot the same quantity of phosphoric acid (150 pounds per acre, 

 which waj> determined by analyzing the materials used). 



