MANURES, LIME AND FERTILIZERS 67 



of sand or coal ashes, and the deficiency made up as above stated, 

 but the feasibility of this plan has not been tested. 



"The problem, however, was not to determine to what extent 

 stable manure may be displaced by commercial fertilizers, but rather 

 to what extent the latter may be used in connection with an abun- 

 dance of the former. We have taken the conditions as we find them 

 in most gardens and greenhouses, and the verdict of our experi- 

 ment is that under such circumstances, and with the crops grown 

 in this experiment, there is likely to be no profit arising from the 

 use of the commercial fertilizers named." 



In the same connection, Prof. Green writes: "The 

 growth of plants upon the separate plots was noted from 

 time to time, and weights and measures taken at time of 

 harvesting. No effect from the use of any fertilizer could 

 be detected; the plots were as uniform as though the 

 same treatment had been given to all. The crops grown 

 were lettuce, radishes and tomatoes." 



Complete fertilizers were used in larger amounts than 

 is customary out of doors, but not so freely as to injure 

 the plants. It is probable, though, that with the decreas- 

 ing supply of city stable manure, greenhouse growers and 

 market gardeners will be forced to resort more largely to 

 the use of commercial fertilizers. It is also probable that 

 less manure and the skillful use of fertilizers would give 

 just as good results as the exclusive use of large amounts 

 of manure. 



Sources of nitrogen. Some nitrogenous fertilizers be- 

 come available much more quickly than others. High 

 solubility is desirable, for the grower can then adjust the 

 supplemental applications more accurately to the needs of 

 the crop. It is assumed that every grower is using at least 

 some stable manure, and the practical and often perplex- 

 ing problem is, how much and what kind of fertilizer is 

 needed to produce the best results. 



Of the mineral materials which contain nitrogen, 

 nitrate of soda is used the most generally, and no doubt 

 more largely as a source of nitrogen than any other 



