l8 MAINE AGRICUIvTURAL EXPERIMENT STATION. I909. 



ANALYSES OF MANUFACTURERS' SAMPLES. 



In the tables there are given the results of the analyses of the 

 manufacturers' samples of licensed brands. The tables include 

 all the brands which were licensed to March, 1909. Dealers are 

 cautioned against handling any brands not given in this list with- 

 out first writing the Station. 



The figures which are given as the percentages of valuable 

 ingredients guaranteed by the* manufacturers are the minimum 

 percentages of the guarantee. If, for instance, the guarantee is 

 2 to 3 per cent of nitrogen, it is evident that the dealer cannot 

 be held to have agreed to furnish more than 2 per cent, and so 

 this percentage is taken as actual guarantee. The figures under 

 the head of "found" are those showing the actual composition 

 of the samples. 



VALUATION OF FERTILIZERS. 



The chief use of fertilizers is to supply plant-food. It is 

 good farming to make the most of the natural resources of the 

 soil and of the manures produced on the farm, and to depend 

 upon artificial fertilizers o'^ly to furnish what more is needed. 

 It is not good economy to pay high prices for materials which 

 the soil may itself yield, but it is good economy to supply the 

 lacking ones in the cheapest way. The rule in the purchase of 

 costly commercial fertilizers should be to select those that sup- 

 ply, in the best forms and at the lowest cost, the plant-food 

 which the crop needs and the soil fails to furnish. 



Plants differ widely with respect to their capacities for gath- 

 evi^g their food from soil and air; hence the proper fertilizer 

 in a given case depends upon the crop as well as upon the soil. 

 The fertility of the soil would remain practically unchanged if 

 all the ingredients removed in the various farm products were 

 restored to the land. This may be accomplished by feeding the 

 crops grown on the farm to animals, carefully saving the 

 manure and returning it to the soil. If it is practicable to 

 pursue a system of stock feeding in which those products of the 

 farm which are comparatively poor in fertilizing constituents are 

 exchanged in the market for feeding stuffs of high fertilizing 

 value, the loss of soil fertility may be reduced to a minimum, or 

 there may be an actual gain in fertility. 



