GREEN-MANURES 241 



for the operation. Study the action of the plow which is being 

 used and see if the depth of the plowing, the inclination of the 

 furrow slice, and the covering of the green material is as it 

 should be. 



Calculate the weight of the crop being turned under and with 

 this as a basis, figure the pounds of water, dry matter, nitrogen, 

 phosphoric acid and potash being placed in the soil per acre. If 

 the crop is a legume, make a guess as to the probable gain of the soil 

 in nitrogen. Is this nitrogen available or unavailable ? 



Exercise II. — Green-manure and the rotation. 



Take a number of good practical rotations and indicate where, 

 in the succession of crops, a green-manure might be introduced. 

 Encourage the pupils to bring data from their home farms for this 

 study. Tabulate such material and study it in the class room. 

 Also bring up the question in relation to gardening and trucking. 

 Discuss the necessity, advisability and ways of introducing a green- 

 manure under such conditions. 



