242 Report on Crop Production op the 



Calcium carbonate was added in a quantity entirely sufficient 

 to neutralize any possible acidity which might arise from the 

 use, by the plants, of bases in excess of the use of acids from 

 the various salts. This caused the reversion of the acid phos- 

 phate, of course, but did not thereby render the phosphoric acid 

 unavailable. 



In part of the experiments of 1899-1900 the ammonium nitrate 

 was replaced by calcium nitrate. The various salts used were 

 supposed to be chemically pure. It was discovered, when too 

 late, that some of those used in 1S0S-1S99 were not strictly free 

 ifrom potassium, and for that reason in the first year's experi- 

 ments all of the first four boxes in the series received more or 

 less potassium outside of that derived from the water and sand. 

 In the second year's work the chemicals are regarded as having 

 been strictly free from potassium. 



It is not at all certain that the compounds used to feed these 

 plants were the best in kind and proportion that could have been 

 selected for promoting thriftiness of growth. Unquestionably 

 the plants did not thrive as they would under usual forcing 

 house conditions, but whether this was due to the peculiar 

 character of the soil or to a lack of adaptation on the part of the 

 food supply is not known. Probably both factors exerted an 

 influence. 



The icater. — The water used in these experiments was distilled. 

 It was not entirely pure, however. In the second year's work 

 (1899-1900) the water was taken to the forcing house in twelve 

 large lots and the percentage of potash was determined in each 

 lot. The quantity of potash present was found to vary from 

 -.0008 to .0074 gram in ten liters of water, averaging .002 gram. 

 As the amount of water applied per can did not exceed eighteen 

 liters in any case, the potash derived from the water per can 

 was not over .0036 gram. The water was applied according to 

 ^he judgment of the one in charge of the forcing house. 



