366 HOW THE NEEDS OF SOILS MAY BE DETERMINED 



Points to Observe. — In making liming tests, best contrasts 

 in results can be secured when a definite line is made between 

 the "limed'' and "no lime'' areas. To accomplish this, the west 

 portion of a field should be limed when the wind blows from the 

 east, or the east portion when the wind blows from the west. When 

 the limed plot extends through a field, the windward border of 

 the plot, at the time the lime is applied, should be selected for the 

 best contrasts. The same point should be observed in applying 

 certain fertilizers broadcast. _ 



Sometimes when two or more adjacent plots are to be fertilized 

 differently, it becomes necessary to mix certain of the fertilizers 



Fig. 232. — Potash alone compared with potash and acid phosphate. (Wisconsin Station.) 



with moist soil to prevent the wind from blowing the fertilizer 

 over the other plots. In such tests it is usually best to apply 

 the fertilizers by hand, and then mix them thoroughly with the 

 soil by disking or "dragging." 



Avoid the laying out of test plots adjoining and parallel to 

 fences. Extend them into or through the field away from fences. 

 Long strips are better than square plots. _^^^^' ' \ 



Observing the difference in growth on the various plots is not 

 sufficient in determining the final and comparative results. It 

 is always best to obtain the results by weighing the whole crop and 

 determining the actual yields. When it is not convenient to 

 harvest each plot separately, the crop on an average square rod 

 on each plot may be properly harvested, and results calculated 

 to acre basis. 



