48 THE ROTHAMSTED EXPERIMENTS. 



the value of farmyard manure as a chemical manure, 

 is the inferior value possessed by much of the nitrogen 

 it contains, as compared with the nitrogen in such 

 artificial manures as nitrate of soda and sulphate of 

 ammonia. According to the Eothamsted experiments, 

 weight for weight, the nitrogen in farmyard manure 

 is not half as valuable as it is in sulphate of ammonia. 

 Much of the nitrogen becomes only very slowly avail- 

 able ; not a little of it perhaps actually takes years to 

 be converted into nitrates. 1 



Thus, with regard to the direct value of farmyard 

 manure as a manure, we have seen 



1. That it contains a very small quantity of the 

 three fertilising ingredients. 



1 This aspect of farmyard manure has been ably stated by Mr F. J. 

 Cooke, a well-known Norfolk farmer. In commenting on the results 

 of the Rothamsted experiments, he says : " It is clear enough that the 

 faith of the farmer in the soil-enriching character of his home-made 

 manure is amply justified, the only question being, indeed, if this 

 quality be not too highly appreciated. It is not, after all, so much 

 by the fattening of our land as by the bounty of the crop grown upon 

 it that we reap the fruit of our exertions. The man of scientific 

 mind keeps his purpose fixed on the production of good crops mainly, 

 and the cheapest way to grow them. The experiments under con- 

 sideration show that richness of land may be purchased much too 

 dearly, and that"' richness of crop by no means bears the necessary 

 relation to richness of soil which has sometimes been imagined. We 

 may boast of the ' lasting qualities ' of our dung, but the answer of 

 science by these experiments is, that so great is the last that the life 

 of one man may not be long enough to exhaust it. In the extra- 

 vagant use of dung, therefore, such considerations, amongst many 

 others, as length of purse, as well as length and character of tenure, 

 must clearly be taken into account." 



