50 



CONSERVATION OF THE SOIL 



EXERCISE 



1. The Maryland Agricultural Experiment Station grew 

 65.1 bu. of corn on land which had been given one applica- 

 tion of rotted manure ; on adjoining land it grew 70.7 bu. 

 of corn from an equal amount of fresh manure. What was 

 the per cent of gain from using fresh manure ? 



2. At the same station fresh manure when used as a top- 

 dressing, instead of being plowed under, resulted in a gain 

 of 10 bu. of corn per acre. The yield of corn on the land 

 where the manure was plowed under was 87 bu. ; what was 

 it on the other ? What was the per cent of gain from using 

 the manure as a top-dressing ? 



3. On an unman ured piece of land 16 bu. of wheat was 

 the average yield per acre. The same land when given a 

 top-dressing of fresh manure made an average yield of 

 20 bu. What was the per cent of increase of the manured 

 land over the umnanured ? 



MIXING FERTILIZERS ON THE FARM 



59. It is usually much cheaper and more satisfactory to 

 buy the fertilizer ingredients and mix them on the farm. A 

 fertilizer labeled 2-8-4 contains 2% nitrogen, 8% phos- 

 phoric acid, and 4% potash. (In some states the order of 

 naming the ingredients is phosphoric acid, nitrogen, and 

 potash.) 



