314 THE SMALL GRAINS 



the rate of 1 pound to each 1000 pounds weight of animal each day, 

 is taken directly from the stable to the field. This phosphated 

 manure is spread on the clover sod in the fall or early winter at the 

 rate of 10 tons to the acre, and then plowed under for corn, the 

 plowed land being dressed with limestone, 1 ton to the acre. The 

 oats receive no treatment, but the wheat receives a complete fer- 

 tilizer of 200 pounds steamed bone meal, 100 pounds acid phosphate, 

 and 40 pounds muriate of potash, in the fall, and 60 pounds nitrate 

 of soda in the spring. The result has been an 8 years' average of 

 77 bushels corn to the acre, 61 bushels oats, 33 bushels wheat, and 

 3 f tons hay, an increase over the unfertilized yield of 50 bushels 

 corn, 31 bushels oats, 21 bushels wheat, and more than three times 

 as much hay. 



340. Green manures are any crops grown and plowed 

 under green for soil improvement. Through their decay, 

 soil humus is increased, and certain mineral elements 

 already present are rendered available. They become a 

 necessity for successful crop cultivation, in absence of 

 barnyard manure, but may also profitably supplement 

 the latter. 



Aside from the plant-food added, green-manures affect 

 favorably the physical condition of both sandy and clay 

 soils. Light sandy soils are prevented from rapidly 

 drying out by reducing the evaporation and percolation. 

 They are made more compact also, and the added humus 

 increases the moisture capacity. On the other hand, 

 clay soils are opened and aerated by green-manures, and 

 made less stiff and less liable to wash where hilly. Ex- 

 treme soil temperatures are modified by green-manuring. 

 Green-manures, like stable manure, tend to increase soil 

 acidity and therefore their application must be accom- 

 panied by liming. 



The humus from green-manures not only holds moisture, 

 but retains in the soil soluble nitrates, potassium, and 



