Nkw York Agkigultural ExrBRiMENT Station. 325 



In the following year, where a combination of phosphate of 

 ammonia and sulphate of potash was used, supplying the soil 

 .0004 per et. of potash and .0001 per ct. each of phosphoric acid 

 and nitrogen, the seed did not germinate well nor the plants 

 grow vigorously. 



Sulphate of ammonia in combination gave poorer results in 

 every case than the other forms of nitrogen. As in previous 

 tests, the results with muriate of potash were less favorable 

 than those with the sulphate. Carbonate of potash-magnesia with 

 dissolved bone black and dried blood or with double superphos- 

 phate and nitrate of soda gave very satisfactory growth. Gocss- 

 mann concludes that soluble saline compounds should not be 

 used in excess in lettuce fertilizers, especially not under glass. 



Jenkins and Britton^ report interesting data on the amount of 

 nitrogen taken from the soil by forced lettuce and the quantity 

 necessary to supply in fertilizers to meet this demand. The soil 

 used was sifted anthracite coal ashes mixed with 5 per ct. of 

 peat moss and fertilized with sufficient quantities of chemicals. 

 Simpson White-seeded Tennis Ball lettuce was, after two trans- 

 plantings, grown to maturity on this medium. 



The lettuce was of good quality, though not claimed to be 

 equal to the best grown in rich natural soil. The time of growth 

 is not stated. The draft on the soil by the entire plants of 1000 

 heads of lettuce thus grown was 282.6 grams nitrogen, 87.7 

 grams phosfthoric acid and 621 grams potash. To meet this 

 demand would require fertilizers equivalent to 1105 lbs. per 

 acre of nitrate of soda, 331 lbs. dissolved bone black and 391 lbs. 

 muriate of potash. 



In 1897 Watts^ published a report of some experiments in 

 which nitrate of soda gave good results when applied three 

 times to loose lettuce in pots. It was applied to each pot at the 

 rate of f oz. dissolved in one-half pint of water, making the total 

 amount for the season 1^ ozs. per plant. 



"Jenkins and Britton. Conn. State Sta. Ann. Rept. 1895:93-95. 

 •Watts, R. L. Tenn. Agr. Ejp. Sta. Bui., X, 2:2T. 



