164 SOIL PHYSICS AND MANAGEMENT 



It is very important that the manure should be handled in such 

 a way as to lose as little as possible. The best plan is to scatter 

 it on the land as soon as practicable after it is produced. If the 

 fertility is leached out then it goes into the soil, and if the manure 

 becomes dry there is essentially no loss. The farm should be man- 

 aged, if possible, so there would always be a place to haul manure. 

 If this is not feasible under the system followed or if the fields be- 

 come too wet to draw the manure upon them, the problem of pre- 

 venting loss becomes an important one. It is well to remember 

 that the greatest losses are due to fermentation and leaching. 



(a) Fermentation. The process of fermentation is largely re- 

 sponsible for loss of nitrogen and organic matter. It is practically 

 impossible to prevent it entirely, but it should be reduced to a 

 minimum. When manure, particularly from horses, is thrown into 

 a pile it soon begins to heat. This indicates that bacterial action 

 or fermentation is taking place. The organic matter of the manure 

 is being decomposed and nitrogen in the form of ammonia is given 

 off, resulting in large losses. In connection with this process, 

 other organisms may work, causing " fire fanging," resulting in 

 a light, powdery form of manure of little value. A process of 

 fermentation takes place in cow manure or compact manures that 

 results in rotting without so much loss. This is known as putre- 

 faction and is due to anaerobic bacteria or those working without 

 oxygen. The fermentation may be largely prevented by excluding 

 the air, since oxygen is necessary for the process. This may be done 

 in two ways, first by allowing stock to trample the manure, thus 

 compacting it so much as to exclude the air, and, second, keeping 

 the manure very wet. 



(b) Leaching. The greatest loss of manure is due to leaching, 

 as .it affects all constituents and elements alike. The colored liquid 

 draining from the manure heap carries large amounts of valuable 

 material away in the drainage waters. The Ohio Station found 

 that manure from steers exposed for three months, January to 

 April, decreased in plant food value per ton from $3.01 to $1.85, or 

 there was a loss of $1.16, or 38.6 per cent. The loss of organic 

 matter was fully as great. Leaching may be prevented by keeping 

 the manure in a shed to protect it from the rain. Tf exposed, it 

 should be kept in a concrete pit or tank to prevent loss by leaching 

 and very wet to prevent heating. Horse manure is the most diffi- 

 cult to keep because of its tendency to heat, owing to its looseness 



