402 AGRICULTURE OF MAINE. 



Again, with respect to a twelve-years' series on mangolds, 

 Mr. Hall writes : — "Here is will be seen that potash increased 

 the crop in every case except where nitrate of soda had been 

 used as the nitrogenous cross dressing, in which case the soda 

 liberates so much potash from the soil that specific application 

 of potassic manures is unnecessary." 



FERTILIZER FORMULA FOR I915. 



While the speaker believes it to be important for Maine that 

 as much potash be put in the commercial fertilizers as can be 

 used under the present circumstances, it is more than probable 

 that by more thorough preparation of the soil, the use of liberal 

 quantities of high grade fertilizers carrying equally as much 

 nitrogen as in the past, part of which is present as nitrate of 

 soda, and perhaps rather more phosphoric acid, and with as 

 much potash as can be obtained, there will be no serious short- 

 age in the crops for 191 5. 



While there are some chemicals, such as lime, gypsum, and 

 chloride, nitrate and sulphate of sodium, which are supposed 

 to be more or less effective in making soil potash available, 

 they can be only slightly depended upon. When potatoes enter 

 into the rotation lime cannot be used because of the danger of 

 scab. Gypsum (land plaster) and sodium chloride (common 

 salt) are about the only chemical agents in addition to nitrate 

 of soda that can economically and safely be used. All commer- 

 cial fertilizers carry as a by-product in the manufacture of acid 

 phosphate, considerable quantities of gy^psum. As land plaster 

 is not an expensive product it probably will be advisable to use 

 it at the rate of perhaps half a ton per acre. It will also be 

 advisable to use a small amount, perhaps 300 pounds per acre, 

 of common salt. Nitrate of soda should enter into the mixed 

 goods as a source of a part of the nitrogen of the fertilizer. 



If the present conditions continue it is planned to use both 

 at Highmoor Farm and at Aroostook Farm in 191 5 a fertilizer 

 carrying about five per cent of nitrogen, eight to ten per cent of 

 available phosphoric acid, and all the potash that we can obtain 

 up to seven per cent. One-third of the nitrogen will be in the 

 form of nitrate, one-third in the form of ammonia salts and 

 one-third in the form of high grade organic nitrogen. The 



