SOIL FERTILITY 



Rich Soils and Poor Soils 



Notice carefully different fields in your vicinity to 

 see which naturally produce good crops and which pro- 

 duce poor ones. Get samples of the soil from the dif- 

 ferent fields and examine them as to their fineness and 

 the comparative amounts of clay, sand, and humus. 

 Stir each soil in a tumbler of water and then let it settle. 

 After it has settled notice the different layers. 



Commercial Fertilizers 



In the school or home garden, plant quick-growing 

 crops like radishes or lettuce, using a small amount of 

 commercial fertilizer for part of each row and omitting 

 it for the rest. Watch the crops as they develop and see 

 which starts the sooner and grows the more vigorously. 



Learn which farmers in the vicinity use commercial 

 fertilizers and for what crops. Find out whether such 

 use is repaid by the increased yields of the crop. 



Root Nodules 



Carefully dig up the roots of clovers, peas, beans, 

 alfalfa, vetch, or other members of the great family of 

 legumes, and wash the soil out in water. Then examine 

 the roots to see whether there are small nodules or tuber- 

 cules upon them. These nodules contain millions of 

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