If humus in soil under cultivation is perishable, ought it not 

 to be the farmer's first care to keep good the quantity first 

 found in the virgin soil ? 



In addition to the humus returned to the soil in manure, 

 from forage fed to stock, and by plowing under stubble and roots, 

 do you think it a good plan to sow some cover-crop in corn rows 

 at last cultivation, and on oat and wheat stubble as soon as the 

 crop is off, for plowing under the following spring ? 



What are good crops for this purpose ? 



Which of these are leguminous plants ? Name all the kinds of 

 leguminous plants you know ? 



Why is it advised to plow under the green-crops as soon as the 

 land can be worked in the spring ? 



Do you think a rotation of crops helps the soil to bear the 

 strain of successive cropping ? If so, why ? 



