320 ELEMENTS OF FARM PRACTICE 



invested? How large an income must he have gotten to pay 6% 

 interest on his investment? 



2. In 1915 A's farm is worth $100 per acre; he has $800 worth 

 of horses, $1,000 worth of cattle, $150 worth of hogs, $50 worth of 

 poultry, and $1,000 worth of machinery. How much has he invested? 

 What income must he receive to pay 6% interest on his investment? 



ROTATION OF CROPS 



Definition. — Rotation of crops means changing the crops 

 year after year on a field, so that no field grows the same 

 kind of a crop for several 3^ears in succession. 



If a field were sown to wheat one year, barley another 

 year and clover another, we would say that the crops are 

 being rotated on that field. 



Good farmers are practicing more or less some plan of 

 crop rotation on their farms, because they have found 

 from experience that their fields yield better, if the crops 

 are changed about, than when one field raises the same 

 kind of crop for several years in succession. 



Larger yields mean larger incomes. Larger incomes 

 enable farmers to have better homes, better schools, better 

 roads; in short, to live better in every way. We should, 

 therefore, be interested in knowing more about conditions 

 which have a tendency to increase yields. 



Systematic Rotation. — A still better practice, because it 

 usually results in larger yields and more profit, is to rotate 

 crops in some regular order, so one may know several years 

 in advance what crop will be grown on each field. Such a 

 plan of cropping is called a systematic rotation. A very 

 simple form of a systematic rotation is to divide the tillable 

 land into three fields of about equal size and crop them as 

 shown in the following chart: 



Field A. Field B. Field C. 



1st. year Oats. Clover. Com. 



2nd. year Clover. Corn. Oats. 



3rd. year Com. Oats. Clover. 



From the above chart one will see that each field has a 

 different crop on it each year for three years, but that the 

 farm is producing the same crops each year. That is, one 

 field is in corn, one in oats and one in clover. In this rota- 

 tion corn always follows clover, oats always follows corn 

 and clover always follows oats. If a person is practicing 



