CROP ROTATION EN RELATION 10 SOIL PRODUCTIVITY 
53 
// a s // // 20 20 £■ 20 20 
4, jL 4- 4. 
C//£/V/C24L-/ : £&T//-/<Z££ &&#/£S Ms?A/</&E S&G/&S 
"gsg^ YZEAJ? /*7T//C>t/T >Z07??T/0// >?//£> ^£jeT//-/2£JZ 
^g*/// &e&wr£P to c/s&Af/csL rtzer/L/z&z 
'-'HA G**'" CG&p/nEP to /&*#*//?£ 
Fig. 9.-— Chart showing the effects of soil reaction on the efficiency of rotation and the use of fertilizers, 
as indicated by the yields of oats at Wooster, Ohio. The plot numbers are indicated under the 
bars. L indicates the plots receiving lime. This shows what portion of each yield is credited to 
cultivation alone, the increase effected when to cultivation is added rotation or the use of fertilizers, 
and the total increase resulting when to cultivation are added the conjoint effects of rotation and 
the use of fertilizers. (Compare with data in Tables 49 and 50.) 
