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LESSONS IN AGRICULTURE 



inches, and about 2 feet deep. Describe the difference 

 between the soil and sub-soil. Repeat this experiment 

 by digging the hole on a steep slope. Account for 

 the difference between the soil of the two places. Which 

 do you think will grow the better crop? How deep is 

 the soil in both places? 



5. Name the places at which you see soil forming, 

 and explain agency in each case. 



7. Soils on the Home Farms 



Each student in the class should bring samples of 

 soil from the home farm. Place the samples in sepa- 

 rate vessels on a table where all can observe them, and 

 fill out the following outline: 



Free Bulletins, U. S. Dept. of Agriculture 

 Bureau of Soils 



Circular No. 4. Soils of Salt Lake Valley, Utah. 



Circular No. 8. Reclamation of Salt Marsh Lands. 



Circular No. 13. The Work of the Bureau of Soils. 



Table showing fertilizing substances in average soils: 



Pounds per Ton. 

 Soil. Nitrogen. Phos. Acid. Potash 



Loam 7 Ibs. 3 Ibs. 8 Ibs. 



Clay 3 Ibs. 3 Ibs. 15 Ibs. 



Sand 1 Ib. 2 Ibs. 5 Ibs. 



(Adapted from Stockbridge.) 



Problems 



1. Suppose soil is cultivated to the depth of 4 inches. 

 How many cubic feet of cultivated soil per square foot 

 of area ? Per square yard ? Per square rod ? Per acre ? 



