THE CHEMISTRY OF THE SOIL. L05 



will be found useful : Make a heap of alternate layers of peal or peaty loam, 



or vegetable refuse, and w I ashes, or make a hole and fill it with these 



substances in alternate layers, moisten the heap with urine or slop water, and 

 allow to ferment for a few months, when it may be turned over. Tha 

 addition of stable-manure, dung, and in fart all refuse matter of the farm, 

 will benefit such a heap, which may be thus made the means of utilising a 

 great deal of valuable fertilising material which would otherwise he thrown 

 away. 



The above remarks apply to un leached ashes, such as are obtained from 

 the burning of timber. 



Leached ashes contain practically little but lime and carbonate of lime, as 

 the potash and phosphoric acid are for the most part leached out. Their use 

 and action are similar to those described under the heading of carbonate of 

 lime. They may be sometimes economically used instead of this substance, 

 but in no case will the farmer derive any benefit from leaching his own ashes 

 As the above analyses will show, it is chiefly for tht sake of their potash that 

 wood-ashes are used, and they may be regarded as potash manures. They 

 are not nearly so concentrated a form of this substance as potash salts, and 

 if substituted for kainit it is well to remember that 1 cwt. sulphate or muriate 

 of potash contains about the same quantity of potash as 12 or 13 cwt. 

 wood-ashes. 



The fertilising value of wood ashes is, for the reasons referred to in the 

 preceding paragraphs, very variable, even ashes from the same timber 

 giving different figures according to the way they are burnt and the amount 

 of weathering or leaching they have undergone. The potash content is 

 especially liable to variation, as potash salts are volatile to some extent, and 

 when the wood is burnt in contact with a hot bright flame, a considerable 

 quantity is lost by volatilization, whereas when the timber smoulders away, 

 little, if any, is so lost. 



Sea- weed as a Manure. 



Sea-weed is not at a first glance a very promising fertilising material. It 

 has, when fresh, a fertilising value somewhat lower than that of farmyard 

 manure, and its large content of water prevents its carriage in a fresh state 

 to any distance with economy. Even at the distance of a few miles from 

 the coast the cost and labour of transport places it out of court as a fertiliser. 

 Its use is, therefore, limited to farms situated immediately upon an accessible 

 coast ; but in such cases there is no doubt that it might be applied with 

 advantage more frequently than at present. 



In the coastal districts of Great Britain (especially of Scotland and Ireland), 

 France, Norway, and the United States, sea-weed is largely used as manure. 

 The general custom is to fork it straight into the land like dung, and this is 

 the best method for such sea-weeds as decompose rapidly, and can be easily 

 distributed, such as the different varieties of kelp and ribbon-weed. These 

 may be strewn over the land or ploughed lightly in, and rapidly decompose 

 and disappear. For the tougher kinds, such as eel-grass, it is usually 

 recommended to compost with lime. This is done by building a stack of 

 alternate layers of sea-weed and lime, the layers of sea-weed being about 

 6 inches deep, and covered with lime. The whole stack may be conveniently 

 covered with gypsum to prevent loss of ammonia. The heap is left for two 

 or three months, and then turned over at intervals until well rotted. It is 

 doubtful whether composting is economical in the case of the more readily 

 decomposed varieties above mentioned. 



