364 HOW THE NEEDS OF SOILS MAY BE DETERMINED 



everything. The best it can do on soil problems is to establish 

 certain fundamental principles that may be applied generally. 

 The simpler problems and those which have to do with the soils 

 on individual farms are left to the leading farmers to work out 

 either for themselves, or under the direction and supervision of 

 the Experiment Station, the College of Agriculture, or of the 

 County Agricultural Representative. Such tests can be made 

 simple, and need not interfere in any way with the farmers' plans. 

 A few illustrations follow: 



Testing the Value of Agricultural Lime. Even though the 

 Experiment Stations have proved the value of liming acid soils, 



Fence 



FIG. 230. How to demonstrate the value of lime and acid phosphate. (See page 232.) 



it is important to continue to demonstrate the value of agricultural 

 lime on individual farms and on different soils. Such tests are 

 valuable, not only from an educational point of view, but, when 

 rightly conducted, afford the farmer a basis for figuring the in- 

 creases in net returns from this method of soil improvement. 



When an entire field is to be limed, an acre strip, or a one-half 

 or a one-fourth acre area, may be left unlimed (Fig. 228). When 

 only a small area is to be limed as a trial, the limed strip may 

 extend through a field or project into it; or a portion of a field 

 may be limed. Both limed and unlimed areas should be cropped 

 the same, the same quality of seed used, and the lots should receive 

 like treatment, except for the lime (Figs. 229 and 230). 



Trying Fertilizers. In trying fertilizers, it is comparatively 



