FERTILIZERS FOR VEGETABLES 



225 



President Greffrath: This is a round table talk. We 

 have some time before us. Now is the time to ask any ques- 

 tions on the subject of fertilizing crops. 



Form of Phosphorus. 



Question: Why do you recommend phosphate instead of 

 bone? 



Professor Van Slyke: The action of bone is slow. 

 Where you want quick work, there is nothing that works so 

 satisfactorily as the acid phosphate. Bone will become avail- 

 able in time if you can wait, but where you want immediate 

 work, you must use acid phosphate. Phosphoric acid in the 

 form of bone at present prices will cost you somewhat more, 

 especially if you take into consideration availability. The 

 reason I mention only a limited number of commercial ma- 

 terials is based in large measure upon the prices prevailing 

 at the present time. The nitrogen in dried blood at present 

 prices will cost you about thirty cents a pound, in nitrate of 

 soda, fifteen. While the dried blood is an excellent material 

 to use, it will have to be under very unusual circumstances 

 when you can afford to pay thirty cents a pound for nitrogen 

 in this form. 



Form of Nitrogen. 



Question: Would you consider fish tankage to take the 

 place of dried blood? 



Professor Van Slyke: Yes, but the cost of nitrogen in 

 that is higher than in nitrate. In some cases especially 

 where you want a little slower action, it is better. The 

 ground fish is apt to be somewhat coarser. One unfortunate 

 fact is that the supply is so limited. Cotton seed meal as a 

 source of organic nitrogen in fertilizer is very desirable, but 

 the price is prohibitive in the North. 



A Member: I made an experiment on cotton seed meal 

 on a little plot of celery, and I never had a nicer plot than 

 that. 



For Lettuce. 



President Greffrath : What formula would you recom- 

 mend for a good lettuce fertilizer for a summer crop on muck 

 land soil, with head lettuce? 



