1901.] PUBLIC DOCUMENT — No. 38. 113 



Practical Advice on Fertilizers for Onions. 

 Although further invcstiiiations are called for concerning 

 the many questions connected with using fertilizers for 

 onions, it is believed that the results thus far obtained justify 

 the following advice : — 



1. JNIixed fertilizers which are to be used for the culture 

 of onions where nothing else is employed should contain 

 about 3 to 4 per cent, nitrogen, 5 to 6 per cent, available 

 phosphoric acid and 8 to 10 per cent, potash. It is believed 

 that the nitrogen of such fertilizers should be derived in 

 about equal proportions from nitrate of soda, dried blood and 

 dry ground fish or tankage. It is further believed that the 

 source of potash should be either the sulfate or carbonate. 

 Such a fertilizer might be required in amounts varying from 

 1 to 11/^ tons. 



2. If a home mixture of materials is to be made, it is be- 

 lieved that it should supply 60 [)Ounds of nitrogen, from 90 

 to 100 pounds of phosphoric acid and 160 to 200 pounds of 

 potash per acre. It is believed, further, that the nitrogen, 

 as stated above, should be derived in part from nitrate of 

 soda and in part from animal materials. It is believed that 

 the phosphoric acid should be derived mainly from acid 

 phosphate or dissolved bone-black, and that for potash cither 

 the high or low grade sulphate or the carljonate of potash- 

 magnesia should be employed. As an illustration of a mixt- 

 ure which it is believed Avill suit average conditions, the fol- 

 lowing list of materials is given : — 



Pounds. 



Nitrate of soda, 200 



Dried blood, . ^ 250 



Dry ground fish or tanliage, 200 



Acid phosphate, 700 



For potash, either of the following : — 



High-grade sulfate, 350 



Low-grade sulfate, 700 



Carbonate of potash-magnesia, 950 



These materials should be mixed just before use, spread 

 after ploughing and harrowed in. 



