498 NATURE AND PROPERTIES OF SOILS 



and amount receive careful study, but the rotation should 

 be considered in addition. This is a fundamental principle 

 not only with the application of commercial fertilizers but 

 with liming and the use of farm manure as welL The care- 

 ful fertilization of the rotation, with special reference to the 

 money crop, is the only rational system that should ordi- 

 narily be employed, since it not only cares for the crop on the 

 land but also looks to those that are to follow. The atten- 

 tion that must necessarily be paid to the fertility of the soil 

 in such a system insures the establishment of a soil manage- 

 ment which will result in an economical use of the plant 

 nutrients, while at the same time the yields will be raised and 

 a continuous produetiyity will be provided for. 



