Nitrogen. 121 



Economy in the cost of the nitrogen is the essential point 

 to be considered in the selection of the manure to be used. 

 According to the experiments at Rothamsted, it would 

 appear that, at equivalent prices, a given amount of nitrogen 

 as nitrate of soda may in the long run be more effective than 

 an equal amount as ammonia ; for, contrary to the current 

 opinion, the full effect of the nitrate was not obtained until 

 it had been used for some years on the same plot. The 

 liability to loss of the nitrogen of manure in drainage will 

 vary very much according to the characters of the soil and 

 subsoil, and of the season. But as it is much greater during 

 the late autumn and winter months than in the spring and 

 summer, nitrate of soda, sulphate of ammonia, or Peruvian 

 guano should always be sown in the spring. 



