TESTS FOR SOIL FERTILITY. 159 



potash or muriate of potash; to the fourth, wood 

 ashes (phosphoric acid and potash); to the fifth, 

 common saltpeter (nitrogen and potash); to the 

 sixth, bone flour (nitrogen and phosphoric acid); to 

 the seventh, a concentrated, complete manure, and 

 to the eighth, a dressing of yard manure. Of course 

 this arrangement may be varied according to con- 

 venience or notion. Or, the substances used in the 

 tests may be restricted to a plain superphosphate, 

 a potash salt, and sulphate of ammonia, or nitrate 

 of soda, alone as well as in connection with one 

 another. The plat is then divided into strips across 

 the first division, and one of them planted to wheat 

 or oats, another to corn, a third to potatoes, a fourth 

 to clover, etc. The harvest will most likely give 

 some indication of what element or elements of 

 plant food are needed. 



If, for instance, the complete manures give the 

 best results, we are justified in the assumption that 

 the soil lacks all three chief plant foods; and if, at 

 the same time, the plat fertilized with plain super- 

 phosphate gives next best crops, it will show pretty 

 plainly that phosphoric acid is the very first need 

 to be supplied, and it would be a question to our 

 mind whether barnyard manure, with its rather 

 scant supply of that element, would exactly fill the 

 bill, unless supplemented by an additional dressing 

 of plain phosphate or superphosphate. Whatever 

 element or elements of plant food show the most 

 marked results from their application, are the ones 

 of which the soil is most in need, and which can be 

 expected to give good results at least for a time. 



I am well aware of the aversion that most farmers 

 have to " fussing" in this manner, and of the diffi- 

 culty, in many cases, of obtaining a supply of the 



