COMMERCIAL FERTILIZERS IN HORTICULTURE. 175 



several materials and mix them himself, or, place an order for 

 such mixtures with a reliable manufacturer. Professor Jordan 

 stated that at present the manufacturer dictates to the farmer 

 what he shall purchase, whereas the reverse should be true. 



The question was then asked. What is the relative value of the 

 liquid manure, and the solid product from stables ? 



Professor Jordan had no doubt that the loss, by the waste of 

 the- liquid manure of stables, was in man}' localities fully equal to 

 the amount paid for artificial fertilizers. He believed that where 

 the animals were well fed, the liquid manure constituted one-half 

 or more of the commercial value of the whole product; but this 

 valuable material is, by many farmers, allowed to run to waste. 



To a question concerning the valne of sulphate of ammonia, 

 Professor Jordan replied that he regarded it with favor. It con- 

 tains about twenty per cent of nitrogen. It is less likely to 

 leach rapidly from the soil than nitrate of soda, and is sufficiently 

 available for quick growing crops. 



The question was asked. How does gas-lime rank as fertilizing 

 material? In answer Professor Jordan said that when first 

 received from the gas works, it consists chiefly of lime, with some 

 addition of the sulphate, the sulphite, and the sulphide of lime; 

 the last named, especially, is poisonous to vegetation, but if 

 exposed a while in the open air, the poisonous properties disap- 

 pear. The remaining lime, if put into the soil is of use by its 

 chemical action upon inert matter there present, converting it into 

 plant food. 



In reply to a question whether potash is a necessary element of 

 plant food. Professor Jordan said that if there is anything pretty 

 ^vvell proven, it is that plants must have potash. Plants undoubt- 

 edly contain some potash which is in excess of a minimum 

 portion that is absolutely essential. There is a minimum which 

 plants must have, and which no other compound can replace. 



