PLANT FOODS 29 



Table III. 



Table showing proportions of fertilizing substances in farm 

 crops: 



OUNCES PER BUSHEL. 



Phosphoric 



Crop. Nitrogen. Acid. Potash. 



Wheat 20 oz. 8 oz. 5 oz. 



Rye 17 oz. 9 oz. 5 oz. 



Corn, shelled 14 oz. 5 oz. 3 oz. 



Barley 12 oz. 6 oz. 4 oz. 



Buckwheat 12 oz. 4 oz. 2 oz. 



Oats 10 oz. 3 oz. 2 oz. 



Potatoes 3 oz. i oz. 4 oz. 



Root crops, average 3 oz. i oz. 2 oz. 



POUNDS PER TON. 



Phosphoric 



Crop. Nitrogen. Acid. Potash. 



Timothy or red top hay 20 Ibs. 9 Ibs. 30 Ibs. 



Clover hay 40 Ibs. 10 Ibs. 40 Ibs. 



Tobacco (leaves) 60 Ibs. 13 Ibs. 80 Ibs. 



Straw (average) 10 Ibs. 4 Ibs. 20 Ibs. 



Sugar beets 3 Ibs. 1-5 Ib. 4 Ibs. 



Problems. 



1. How many pounds of each of the three im- 

 portant fertilizers in a crop of wheat that yields 20 bu. 

 per acre? 25 bu. per acre? 



2. A corn crop of 50 bu. per acre ? 60 bu. ? 75 bu. ? 



3. An oat crop of 40 bu. per acre ? 50 bu. ? 60 bu. ? 



4. A barley crop of 40 bu. ? 45 bu. ? 50 bu. ? 



5. A potato crop of no bu. per acre? 120 bu. ? 

 1 50 bu. ? 



6. A clover hay crop of 3^2 tons per acre? 4 tons? 

 5 tons? 



