1922.] 



Town Refuse as Manure. 



689 



and how much from manurially worthless substances which may 

 form a large part of the material. Something could be deduced 

 if the organic matter (which of course includes much of the 

 cinders) were divided in the analysis into easily combustible 

 (vegetable and animal refuse), and not easily combustible 

 material (cinders, etc.) ; but in no case can the analysis give 

 very precise information. 



It would be a mistake to underrate the fertiliser effect of the 

 nitrogen, potash and phosphate in the material, but equally of 

 course it would be inadvisable to put too high a value on them. 

 So far as our present experience goes the chief value of the ash- 

 pit refuse itself lies in its physical effect in lightening a heavy 

 soil, and any manurial action it mav have is to be attributed 

 to any animal or vegetable refuse that may be present. The 

 analysis does not easily show this, although a rough idea may be 

 obtained from the nitrogen percentage. Inspection of samples 

 delivered from London during the past season gave the impres- 

 sion that winter deliveries contained a larger percentage of cin- 

 ders and a smaller percentage of fertilising animal and vegetable 

 matter than the summer deliveries ; hence probably the summer 

 material would have rather a higher value to the farmer. The 

 circumstance that much of the value of the refuse lies in its 

 physical action makes it impossible to put any definite price on 

 the refuse. It should of course be obtainable more cheaply than 

 stable manure. On the other hand dressings of about 10 tons 

 per acre have proved very useful on heavy land for root crops, 

 cabbages, etc.. and a farmer is really justified in spending a 

 certain amount of money to obtain this result. If towm stable 

 manure costs about 12s. per ton on the farm it is probably not 

 far wrong to say that town refuse would be worth, say, 6s. per 

 ton on the farm, and more if the percentage of nitrogen rose 

 above 0.6. 



2. Crushing — Some samples seen by the writer have been 

 ground very finely. A certain amount of pulverisation is desir- 

 able, but it is not clear how far anything is gained bv grinding 

 too finely. The material of course is not like basic slag or 

 mineral phosphate : it does not dissolve in the soil solution, and 

 only the vegetable matter and the bones can gain in value by fine 

 grinding. The actual ashes may even lose in value. 



3. Addition of Richer Materia}. — In some of the northern 

 towms it is found possible to add a considerable proportion of 

 night soil in addition to street sweepings, cattle market manure, 

 slaughterhouse refuse and stable manure. An excellent fertiliser 



R 



