1899.] PUBLIC DOCUMENT— No. 33. 121 



5. To select the various commercial forms of nitrogen, 

 and potash in particular, with special reference to the kind 

 and the desired character of the crop to be raised. 



6. To use as a general fertilizer a mixture of two parts 

 of available potassium oxide, one pari of available nitrogen 

 and one part of available phosphoric acid, in such quan- 

 tities per acre as the conditions of the soil and composition 

 of the crop to be raised called for; allowing, for the com- 

 position of one thousand pounds of green garden vegetables, 

 on an average : — 



rounds. 



Nitrogen, 4.01 



Phosphoric acid, 1.90 



Potassium oxide, 3 . 90 



On account of the frequent cultivation of beans and peas 

 as garden crops, a fertilizer of the following composition 

 suggested itself to me : — 



Parts. 



Available nitrogen, 1 



Available potash, 2 



Available phosphoric acid, ...... 1 



More recent observations confirm the advisability of the 



previously stated rules in a general way; yet they also 

 emphasize the fact that, wherever the quality of the crop 

 controls its economical and commercial value, it seems ad- 

 visable that care should be taken to secure the exclusion of 

 an accumulation of soluble saline substances not called for 

 by the crop. This circumstance deserves particular atten- 

 tion in cultivation under glass, where the body of the soil is 

 limited, and the removal of such substances by percolation 

 to the lower layers offers but little chance of relief. 



In our experiments above described this view of the ques- 

 tion of supplying plant food in the greenhouse has aided us 

 in selecting a series of concentrated chemical manures, which 

 for the above reason are now recommended for patronage : — 



