208 SOILS AND FERTILIZERS 



the usual custom, it needs a complete fertilizer. Rye is a 

 " stronger feeder " and does not have the same need of 

 fertilization. Oats and barley, when spring sown, find more 

 nitrates in the soil, because they are later than winter 

 wheat in starting growth, and, as they can make better use 

 of the soil fertility, they do not require so much fertilizing. 



Corn is a " strong feeder," and, while it removes a very 

 large quantity of plant-food materials from the soil, it does 

 not require that these be added in a soluble form. Farm 

 manure and slowly acting fertilizers may well be used for the 

 corn crop. The long growing period required by the corn 

 plant gives it opportunity to utilize nitrogen as that sub- 

 stance becomes available during the summer, when nitrate 

 formation is most active. Phosphoric acid is the substance 

 usually most needed by corn. 



263. Grass crops. — Meadows and pastures are greatly 

 benefited by fertilizers. The grasses are less vigorous feed- 

 ers than the cereals, have shorter roots, and, when left down 

 for a year or more, the formation of nitrates is much curtailed. 

 There is usually a more active fixation of nitrogen in grass 

 land than in cultivated land, but nitrogen thus acquired 

 becomes available very slowly. Different soils and different 

 climatic conditions necessitate different methods of manur- 

 ing for grass. The use of nitrate is almost always attended 

 with much success, even when used alone, but in most situa- 

 tions a complete fertilizer is profitable. 



264. Leguminous crops. — Most of the leguminous crops 

 are deep-rooted and are vigorous " feeders." Their ability 

 to acquire nitrogen from the air makes the use of that sub- 

 stance unnecessary except in the form of nitrate, which is 

 often very effective in starting a young seeding of alfalfa. 

 The nitrate probably serves to carry the young crop through 

 the period preceding the development of tubercles. Potash 

 salts are almost always profitably used on legumes, and 



