STRONG MANURE. 303 



dition to the soil. Farmyard dung is a mixture of 

 this kind. 



803. In mixing weeds with strong animal manures, 

 it must be borne in mind that their seeds are in many 

 cases not destroyed, although all the rest of the 

 plants may be completely decomposed. Rapid Mid 

 active putrefaction will no doubt destroy the seed 

 also, but this is not desirable ; because, when the 

 manure ferments very strongly, it heats, and a con- 

 siderable portion of volatile matter is sure to be lost. 

 Many seeds have so hard a husk that they will not 

 be at all injured by exposure to mere ordinary putre- 

 faction, and retain therefore their vitality through 

 the decomposition of the dung. Some seeds will 

 even pass uninjured through the stomach of an 

 animal, and not have their vital powers impaired even 

 by the process of digestion. 



804. In most cases it is a waste of manure to burn 

 weeds, and whenever it is practicable it is better to 

 form them into dung by rotting them with other sub- 

 stances ; but when they are full of seeds, or it is not 

 possible to destroy their vitality by so doing, it is 

 doubtless better economy to burn them than to run 

 the risk of a fresh crop for the next season. 



805. As the hedges, banks, and ditches round the 

 manure-yard or mixed heaps are always sure to be 

 well manured, and to get a good deal of the exhala- 

 tions which are lost during the fermentation of the 

 manure itself, so the weeds which grow in such situa- 

 tions are of course peculiarly luxuriant and abundant. 



