1 8 AGRICULTURE OF MAINE. 



In the condition in which it is mined it is thought to be largely 

 unavailable. However, recent investigations seem to indicate 

 that mixing this ground rock with stable-manure or other decay- 

 ing organic materials may make it available. Acid phosphate is 

 the commonest form in which this is used. To make this, a ton 

 of ground rock is treated with approximately a ton of sulphuric 

 acid, making two tons of acid phosphate. When this material 

 liberates the phosphorous in the soil, the sulphuric acid remains 

 behind as a residue. Its continuous use will in time make the 

 soil so sour that some plants will refuse to thrive, notably clover, 

 timothy, beets, etc. The same result follows the continuous 

 use of sulphate of ammonia as a source of nitrogen. It there- 

 fore becomes necessary to apply lime from time to time to soils 

 upon which these fertilizers are extensively used. 



Wood ashes afford one of the best sources of potash, but 

 unfortunately the supply is altogether too limited and the chief 

 source must be the German potash salts, chiefly muriate or 

 sulphate. 



A common belief among farmers is that the chemist might 

 take a sample of their soil and tell them just what it needs. The 

 chemist would do his best, but his answer would have less value 

 than one which the soil itself may give. To test this matter, lay 

 out individual plots of convenient size, say four rods square, 

 making one-tenth of an acre, and apply. to one nitrogen and 

 phosphoric acid, to another nitrogen and potash, to a third phos- 

 phoric acid and potash, to the fourth all three elements and so 

 on, making as many variations as may seem necessary. A care- 

 ful study of these plots will give a far better clue to the needs 

 of the soil than any other plan. 



The purchase of fertilizers is necessary in many of our New 

 England States, yet it affords one of the easiest means of allow- 

 ing money to slip through one's fingers. It is easier to go to 

 the dealer and buy fertilizer than to properly till and manage 

 the land, but it will yield less profit if the conditions for its use 

 are not right. It is far wiser to husband all the home supply 

 of plant-food, and to so handle the soil as to keep it in the best 

 physical condition and well supplied with humus. If then ferti- 

 lizers are used, the farm is in condition to make the best possible 

 use of them. 



