380 



SOIL PHYSICS AND MANAGEMENT 



Average Annual Yields for 16 to 19 Years When Grown Continuously and 

 Under Three- and Five-year Rotations. Ohio Station * 



Rotation gave an increase of 18.5 bushels per acre of corn and 

 for wheat 3.1 bushels, showing again that corn responds to rotation 

 better than wheat. 



PLANNING A ROTATION 



Planning a rotation requires a great deal of care and thought. 

 It should be made not for the present alone but for many years in 

 the future. The probable effect of the rotation adopted should be 

 studied from several standpoints. The effect on the fertility and 

 tilth of the soil should receive careful attention. Will it decrease 

 or increase the organic matter of the soil is a question that should 

 be worked out. If this rotation is practiced, what will be the condi- 

 tion of my farm after fifty years? If you cannot answer this, get 

 the knowledge or the help that will enable you to do so. The rota- 

 tion would depend on the size of the farm to some extent. That 

 for one of sixty acres would not apply to a four hundred-acre farm. 

 The rotation should vary with the character of the soil. A rotation 

 for a heavy, rich, black soil certainly would not be fitted for a sandy 

 soil, or vice versa. Soils low in organic matter should have a system 

 of rotation whose object is to build up the soil in this particular. 

 Acid soils will grow different crops than soils containing limestone. 

 The maintenance of the fertility and tilth of the soil should be a 

 very important factor in determining the rotation. 



The system of farming to be practiced should be one of the con- 

 trolling factors in determining the crops grown. A fruit-grower, 

 a dairyman, a grain farmer, or a stock-raiser would each follow dif- 

 ferent systems. In any system the value of the crops, both those to 

 be used on the farm and those to be sold, must be considered in their 

 selection, since the returns from the crop and its relation to other 

 crops is the thing that should determine its use in the rotation. 

 The most profitable crop should have the most favorable place in the 

 rotation. In the corn and wheat belt these should have this place, 



