258 SOILS AND FERTILIZERS 



be used per acre should be determined by the quality 

 of the seed and the local conditions, as climate and 

 soil, together with any special objects desired as in- 

 fluencing the composition and character of the crop. 



344. Selection of Crops. The selection of the 

 most suitable crops to be grown is largely a local 

 problem and must be determined by climatic and soil 

 conditions. The preferences of farm crops for certain 

 types of soil are discussed in Sections n to 17, and it 

 is not advisable to attempt to grow crops upon soils 

 to which they are not naturally adapted or under un- 

 favorable climatic conditions. Practical experience 

 is the best guide to follow in regard to the selection 

 of crops or the most suitable line of farming to follow, 

 and it will be found that this experience is usually in 

 harmony with the laws governing the conservation 

 of the fertility of the soil. Temporary methods 

 of farming, as exclusive grain raising, can be followed 

 for a short time on new soils but it is desirable that 

 each type of soil should be subjected to a judicious 

 system of cultivation, fertilizing and cropping rather 

 than to the production of one or only a few market 

 crops at random. The selection of the farm crops 

 and their utilization for market or feeding purposes 

 should be determined mainly by the system of farming 

 that is best adapted to the soil of the farm, and the 

 farm should be managed largely with the view of 

 maintaining the fertility of the soil. 



345. The Inherent and Cumulative Fertility of 

 Soils 95 . There is present in nearly every soil a vari- 



