1895.] rUBLIC DOCUMENT — No. 33. 317 



Comments on Table I. 



The first four columns in the table show the weight of 

 straw and grain (dry matter) produced by each pot, and 

 the average from each three pots. The next three columns 

 indicate the gain in dry matter over those pots containing 

 only soil nitrogen. Then follow the comparative yields, 

 nitrate of soda beino: rated at 100. When the average of 

 both straw and grain is considered, it will be seen that the 

 dissolved leather yielded 60.7 per cent, as much as the same 

 quantity of nitrogen in the form of nitrate of soda. The 

 Philadelphia tankage, on the other hand, gave but a slight 

 increase over the no-nitrogen pots ; this slight gain was in 

 the yield of straw. 



In case of the last six pots, where .60 gram of nitrogen 

 was applied in the forms of nitrate of soda and dissolved 

 leather, we find a large amount of straw produced, but very 

 little grain. This, in all probability, can be attributed to 

 two causes : in the first place, in case of the nitrate of soda, 

 one-half the quantity was not applied till early June, and 

 this application might have been too late to enable the plants 

 to take it up and work it over into grain ; in the second 

 place, there might not have been phosphoric acid and potash 

 enough present to have enabled the plants to turn the nitro- 

 gen to account. Twice as much phosphoric acid and four 

 times as much potassium oxide as nitrogen were applied ; 

 the coming year these amounts will be doubled, in order to 

 make sure that a sufiicient quantity is present. The results 

 from these latter pots, therefore, are simply stated, but not 

 further considered. 



