30 PRINCIPLES OF FARM PRACTICE 



kinds of bacteria into ammonia and free nitrogen which pass 

 into the air as gases. Ammonia is often so plentiful around 

 stables that it may be detected by its odor. 



The loss of nitrogen may be greatly reduced if the formation 

 of nitrates can be prevented. Since nitrates are formed by 

 certain bacteria which must have oxygen, an easy method is 

 suggested for preventing their formation; that is, to make 

 conditions unfavorable by excluding air. This may be ac- 

 complished by making the pile as compact as possible, ex- 

 cluding the air by tramping or otherwise pressing the material 

 together as it accumulates. The walls of the pile should be 

 nearly perpendicular, so as to reduce the action of rain and 

 avoid loss by leaching. 



A better plan would be to keep the manure under cover. 

 A practice frequently followed in England and sometimes in 

 this country is a good one. The stables are provided with 

 deep stalls furnished with plenty of straw for bedding. The 

 straw absorbs the liquid wastes and is under cover, and as 

 the manure accumulates it is also thoroughly packed by the 

 tramping of the animals. 



Another method of preventing the deterioration of manure 

 is to spread it on the fields as rapidly as it accumulates. This 

 practice is comparatively easy if manure spreaders are used. 

 It is said that a manure spreader will pay for itself in less than 

 two years by preventing loss of nitrogen and by saving labor. 

 After the manure is spread upon the field the formation of 

 nitrates is an advantage rather than a disadvantage, for they 

 pass into the soil where they are needed as they are formed. 



Use of legumes for supplying nitrogen. Legumes are 

 those plants which belong to the pea family. Some common 

 examples are peas, beans, clover, alfalfa, and vetch. If one 

 of these plants is dug up and its roots examined carefully, 



