42 



BULLETIN- 699, U. S. DEPAETMElSrT OF AGEICULTTJHE. 



Table XVII. — Average annual yields of crops groicn in a four-year rotation on 

 two series of plots on South Farm, Urbana, III., 1903-1915, Inclusive — Contd. 





3 years. 



2 years. 



3 years. 



Not 

 grown. 



2 years. 



Residues, lime, phosphate rock' 



62.4 

 61.5 

 53.8 



58.4 

 63.0 

 63.2 



53.6 

 52.8 

 42.7 



47.6 



48. 5 

 50.2 



47.9 

 46.5 

 2S.6 



29.5 

 49.4 

 48.7 





Bushels. 

 13 7 



Residues, lime, phosphate rock ' 





12.3 



Residues ' 





10 7 



Manure ' 





Tons. 

 84 



Manure, lime, phosphate rock i 





1.17 



Manure, lime, phosphate rock i 





1.34 









1 Plots on which lime was applied were not introduced into the experiment until 1910. 



The results of this experiment point very strongly to the conclu- 

 sion that raw rock used in liberal amounts in connection with organic 

 manures is effective in increasing crop yields. But like many other 

 experiments no data are reported which allow one to determine the 

 relative efficiency of raw rock and acid phosphate. 



In April 1916 Hopkins ^ reported the results of three long-time ex- 

 periments at Cutler, Odin, and Mascoutah, in southern Illinois. 

 These are the only experiments reported by Hopkins of Illinois work 

 comparing the fertilizer value of steamed bone, acid phosphate, 

 ground raw rock phosphate, and basic slag. Crop residues were re- 

 turned to' the land and potash and lime applied. At Odin and Mas- 

 coutah only half of each plot was limed. Fertilizers were applied 

 once during each rotation in sufficient quantity to supply annually 

 200 pounds bone, 333 pounds acid phosphate, 666 pounds raw rock, 

 ajid 260 pounds slag (equal money values at that time). The results 

 of ihe experiments are given below in Tables XVIII and XIX. 



Table XVIII. — Average yields of com, oats, wheat, and hay in two long-time 



experiments. 



Treatment. 



Odin field (1904-1915). 



Corn, 

 3 crops. 



Oats, 

 3 crops. 



Hay, 

 6 crops. 



Mascoutah field (1904-1913).« 



Corn, 

 4 crops. 



Oats, 

 2 crops. 



Wheat, 

 2 crops. 



Residues, 

 Residues, 

 Residues, 

 Residues, 

 Residues, 

 Residues, 

 Residues, 

 Residues, 

 Residues, 

 Residues, 

 Residues, 

 Residues, 



lime, bone, potash 



bone, potash 



lime, potash 



potash 



lime, acid phosphate, potash. 



acid phosphate, potash 



Ume, rock phosphate, potash- 

 rock phosphate, potash 



lime, potash. ,.< 



potash , 



lime, basic slag, potash , 



basic slag, potash... , 



Bushels. 

 33.9 

 31.4 

 26.7 

 27.6 

 30.2 

 29.9 

 32.3 

 27.0 

 27.3 

 21.7 

 32.7 

 27.3 



Bushels. 

 47.8 

 50.9 

 43.9 

 43.9 

 43.5 

 52.8 

 48.4 

 52.2 

 48.1 

 41.1 

 5«.8 

 50.3 



Tons. 

 1.30 



.94 

 1.07 



.64 

 1.19 



.77 

 1.28 



.72 

 1.12 



.61 

 1.27 



.78 



Bushels. 



45.4 

 48.6 

 38.9 

 39.7 

 44.0 

 40.2 

 47.2 

 45.6 

 38.4 

 38.6 

 45.6 

 47.8 



Bushels. 

 38.6 

 42.6 

 37.2 

 27.3 

 37.0 

 42.2 

 38.9 

 37.4 

 40.5 

 31.0 

 43.0 

 33.8 



Bushels. 

 26.3 

 25.9 

 23.6 

 22.6 

 25.4 

 25.7 

 26.7 

 26.2 

 . 25.1 

 20.7 

 26.5 

 25.8 



1 lU. Agr. Expt. Sta. Circular No. 186, April, 1916. 

 * Crops of legumes turned under in 1908 and 19U. 



