EXPERIMENTS OF THE BUREAU OF PLANT INDUSTRY. 



27 



RELATION OF CORN-TILLAGE RESULTS TO SOIL PRODUCTIVITY. 



The results of all the tillage experiments were studied with the 

 object of determining whether the factors which influence grain yield 

 had any effect on the yield of uncultivated corn as compared with 

 the cultivated. For this purpose the experiments were considered 

 in three groups : Group 1 , containing those experiments in which the 

 yield on the cultivated plats fell below 30 bushels per acre; group 2, 

 those varying from 25 to 60 bushels; and group 3, those above 50 

 bushels. By thus overlapping the limits of the various groups it was 

 thought that tendencies would be shown more clearly than if absolute 

 limits were observed. 



Little evidence is shown that any relation exists between these two 

 factors. Group 1, containing the lowest grain yields, shows the 

 average yield on the uncultivated plats to be 97.19 per cent of that 

 on the cultivated; group 2 shows 99.59 per cent; and group 3 shows 

 98.34 per cent. The details are given in Table VII. 



Table VII. — Relation of corn-tillage results to soil productivity. 



Year. 



Experimenter. 



Yield of 

 cultiva- 

 ted plat 

 per acre. 



Yield of 

 unculti- 

 vated 

 plat ex- 

 pressed 

 as per- 

 centage 

 of culti- 

 vated. 



Year. 



Experimenter. 



Yield of 

 cultiva- 

 ted plat 

 per acre. 



Yield of 

 unculti- 

 vated 

 plat ex- 

 pressed 

 as per- 

 centage 

 of culti- 

 vated. 



1906.. 

 1908.. 



Group 1.— Yields less 

 than 30 bushels per 

 acre. 



New Hampshire ex- 

 periment station 



North Carolina experi- 

 ment station 



Callison,N. A 



Bushels. 

 23.3 



11.55 



25.3 



12.2 



22.5 



16.6 



26.7 



29.7 



20.6 

 19.2 

 .. 24 



141.6 



92 



87.1 



66.8 

 115 

 114.7 

 138.8 



80.6 



100 

 101.7 

 107.1 

 114.3 

 95.9 

 90.1 

 97.1 



1886. . 

 1890. . 

 1891.. 

 1893 . 



Group 2.— Yields be- 

 tween 25 and 60 bush- 

 els per acre. 



New York experiment 



station (Geneva) 



Missouri experiment 



Bushels. 

 56.8 



54 



58.4 

 36.3 



58.6 



46.97 



50.3 



41.4 

 48.1 

 52.2 



30.6 

 25.3 

 56.4 

 40.5 



45.7 



42 



26.7 



29.7 



31.25 



37.65 



47.9 



48.8 



50.14 



124.1 



84.6 



1909.. 



Illinois experiment 

 station 







Campbell, J. M 



Cunningham, T. J 



Foster, w. L 



94.7 





do 



79 





1898.. 

 1906. . 

 1907.. 

 1908.. 

 1909.. 



1910.. 



South Carolina experi- 

 ment station 



Purdue experiment 







Rich,E. A. J 



96.4 





Sugar Experiment 

 Station 



95.9 





Cornell experiment 







Wollschlaeger, Gus 



Campbell, J. M 



103.4 



1910. . 



Arlington Experimen- 







Crum,H.C 



21 



5.67 

 16.2 

 15 



97 7 





Ferguson, A. M 



Gardner, E. T 



Howie, P. L 



Anderson, W. B 



Barrett, J. M 



136.5 

 123.7 





Arlington Experimen- 

 tal Farm 







Marvin, Jas. A 



McClelland, C. K 



U. S. Plant Introduc- 

 tion Garden 



23. 9 1 104. 2 

 10.37 77.4 



12.4 87.6 



74.1 





Callison, N. A 



Lambert, F. L 



Leffler, G. V.. 



87.1 

 115.3 

 109.6 





Wollschlaeger, Gus 



Hester, H. C 



23. 78 

 7.1 

 11.26 

 22.06 

 26.9 



99.3 

 53.3 

 88 



93.9 

 100 



Perry, J. B 



108.7 



1911.. 



Purdue experiment 







Hill,L.E 



100.25 





McClendon, S. E 



Prince, A. H 



Rich, E.A.J 



138.8 

 80 6 





U. S. Plant Introduc- 

 tion Garden 



25.52 86 



Tenney, W. P 



170.5 





Bigstaff, T. J 



96.6 







Day, A. P 



87 







97.19 



Finley W W 



92 3 









Fredericks, C. P 



106.4 



257 



