50 



BULLETIN 699, U. S. DEPARTMENT OF AGRICULTURE. 



Table XXV. — Results of seven years' work on Burnside experiment field 



(1909-1915). 





Applica- 

 tion per 

 acre.i 



Yield per acre. 



Fertilizer. 



Com, 

 1909. 



Oats, 

 1910. 



Clover, 

 1911. 



Com, 

 1912. 



Soy- 

 bean 

 hav, 

 1913. 



Wheat, 

 1914. 



Com, 

 1915. 





Pounds. 



2,000 



400 



Bushels. 



\ 3.8 



9.0 



V 14.3 



17.7 

 20.4 

 11.9 



Bushels. 



9.3 



9.0 



11.9 



13.6 

 14.0 

 10.5 



Poun^. 



2,436 



668 



2,168 



2,328 



1,292 



764 



Bushels. 



32.9 



9.5 



45.7 



43.5 

 30.3 

 17.6 



Pounds. 



1,688 



628 



2,272 



2,112 



1,176 



560 



Bushels. 



11.9 



2.5 



19.2 



18.1 

 5.1 

 1.7 



Bushels. 



Potash . 



34.8 





4.9 





800 

 400 

 800 





Potash -. 



46.6 





50.9 



Nothing 2 



18.5 



Potash 



400 



5.3 







' The fertilizers were appUed at rate per E^cre stated in summer of 1908, again at the same rate in 1912, 

 and at one-fourth the above rate in 1915. 

 2 The station states that this plot should not be considered a check plot. 



While the plot treated with raw rock phosphate and potash gave 

 yields below and no better than the check plots in 1909 and 1910, 

 respectively, from then on it forged ahead rapidly, indicating that 

 the crops were benefited by the phosphate treatments after the latter 

 became more thoroughly distributed in the soil through cultivation. 

 The yields of the acid phosphate plots, however, greatly exceeded (in 

 all but one instance) those of the raw-rock plot, even though the less 

 soluble material added over four times as much phosphoric acid to the 

 soil. While no data are given showing their relative natural fertil- 

 ity, it is said that the raw-rock plot was handicapped by being 

 naturally less fertile than the other plots in the experiment field. 



The results of six other experiments comparing acid phosphate 

 with raw rock phosphate, conducted for periods of from three to 

 four years in various parts of the State, are given by Roberts in this 

 same bulletin. Their limited duration, however, coupled with the 

 fact that the weather conditions were very bad during two of the 

 years, render detailed considerations of the results unwarranted in 

 this paper. 



The data presented by the Kentucky station are insufficient to be 

 conclusive, although the results of the field experiment cited did 

 indicate that raw rock, while inferior to acid phosphate, increased 

 crop yields after the lapse of a year or more. 



LOUISIANA. 



Of the 13 experiments with ground rock phosphate or "floats" 

 carried on by the Louisiana Experiment Station, 10 ^ were conducted 

 through periods of from one to four years. These are not repeated 

 in detail. 



iLa. Agr. Expt. Sta., Buls. Nos. 3, 4, 6 (1886); 7, 8, 11 (1887); 14 (1888); 20 

 (1889) ; 28 (1890) (old series). Buls. Nos. 8 (1891) ; 14, 16 (1892) ; 26, 29 (1S94) 

 (new series). 



