FARM MANURES l8/ 



211. Lasting Effects of Manure. --No other manures 

 make themselves felt for so long a time as farm ma- 

 nures. In ordinary farm practice an application of 

 stable manure will visibly affect the crops for a num- 

 ber of years. At the Rothamsted Experiment Station, 

 records have been kept for over fifty years as to the 

 effects of manures upon soils. In one experiment, 

 farm manure was used for twenty years and then dis- 

 continued for the same period. It was observed that 

 when its use was discontinued there was a gradual 

 decline in crop-producing power, but not so rapid as 

 of plots where no manure had been used. The manure 

 applied during the twenty-year period made itself felt 

 for an ensuing twenty years. 



212. Comparative Value of Manure produced on Two 

 Farms. The fact that there is a great difference in 

 the composition and value of manures produced on 

 different farms may be observed from the following 

 examples : 



On one farm 10 tons of timothy are fed. The 

 liquid manure is not preserved and 25 per cent of the 

 fertility is leached out of the solid excrements, while 5 

 per cent of the nitrogen is lost by volatilization. It is 

 estimated that half of the nitrogen and potash of the 

 food is voided in the urine. On account of the scant 

 amount and poor quality of the food no milk or flesh 

 is produced. 



On another farm 7.5 tons of clover hay and 2.5 tons 



