THE SPECIAL FERTILIZERS OF THE FARM. 487 



duly promote the growth of straw, and effects a more thorough distribu- 

 tion of the nitrate by increasing the bulk of the dressing. 



FISH REFUSE contains nearly two per cent, of nitrogen, and one per 

 cent, of phosphoric acid. It answers well as a manure for both wheat 

 and root crops when made into a compost with its own weight of soil, and 

 allowed to decompose before being applied. Fish guano is a manufacture 

 of the refuse from oil-pressing and fish-curing establishments by pressure 

 and treatment with sulphuric acid. 



BULLOCK'S BLOOD is used on a large scale as a manure, but chiefly for 

 mixing with other fertilizers. In its natural state blood contains about 

 three per cent, of nitrogen ; when dried it contains about twelve per cent. 

 1 1 makes an excellent manure for turnips when mixed with bone-dust or 

 phosphatic guano ; and, mixed with peat or mould, may be very advan- 

 tageously applied as a top-dressing to wheat crops and to grass land. 

 SEA- WEED is largely used as a manure on some parts of the coast. It 

 -pecially suited for the potato crop, which requires much potash a 

 _:! mineral constituent of sea- weed. Sometimes it is used as a top- 

 ping to grass land. The action of sea-weed is the same as a green 

 crop ploughed in. It contains all the ordinary constituents of land plants 

 Asitputrifies rapidly, it forms a quick manure. It is applied at the rate 

 of twenty to thirty tons per acre. The usual practice is to spread it on 

 the soil and plough it in ; but it is occasionally formed into a compost with 

 bh and dung. The neighbourhood of the coast is in some districts a 

 distinct element in the value of the land, on account of the sea- weed as a 

 manure, which is thus more cheaply obtained. 



A MANURE. The difficulty in the way of its use is its 



enormous bulk in proportion to its valuable constituents. A ton of city 



ordinarily contains o{ily three pounds of solid matter vi/., one 



pound of organic and two pounds of mineral constituents, the former 



yielding l.-ss than three ounces of ammonia, and the latter half an ounce 



of ph.^ph >rie acid and one and a half ounces of 'potash ; so that in a ton 



i> only about iive ounces of fertilizing nritt'T. One ton 



,'uano may thus contain as much of the fond of plants as twelve hun- 



". According to the market price of the former the 



iiijht thus to be about ti\ per ton. 



My, however, th- comparison between the values of the 



manures; becav found that ten or even twenty timed the 



th- livalenJ of 8ewag is required to produce the effect of guano ; 



uid considering the far gi >-t of utili/.im; the sewage, only a nomi- 



nal price can l>e put upon it. 



