256 THE MONTHLY BULLETIN, 



mineral bases. Thus not only is the potassium made available to a 

 plant but other substances may be brought into solution to serve as 

 plant foods. Again, if more than one substance be dissolved in water 

 the presence of one of the substances in the solution may affect the 

 rate at which the other is adsorbed. As an example, if kainit and 

 nitrate of soda be dissolved together in water the adsori:>tion of potas- 

 sium is reduced and less kainit remains in the soil than would have been 

 the case had not the nitrate of soda been added. 



I trust that this brief and fragmentary discussion of adsorption at 

 least show^s that results of great practical importance are bound to come 

 from further study of the phenomenon. What has been said, too, of the 

 relatively recent discoveries in adsorption may help to demonstrate the 

 complexity of the problems which must be solved before, we can fully 

 control soil-fertility. 



These lengthy statements introduce you, if you are not already 

 acquainted with them, to some of the problems of soil-fertility. I have 

 sought to show the changing attitude of science and the repetition of 

 discoveries in this phase of agriculture so that no one will think that the 

 problem of soil-fertility is solved, nor hail the latest discovery as pos- 

 sibly the last; that it may be seen more cleanly what a complex 

 problem of chemistry, physics and biology the study, to get back to 

 my subject, of fertilizers for fruits becomes; how small a part of the 

 field the few experiments now to be discussed cover; how difficult 

 experimental work with fertilizers is; and how extremely cautious one 

 must be in interpreting results either of experiment or of experience. 



I want now to discuss briefly several comparative tests of fertilizers, 

 for fruits, made at the New York Agricultural Experiment Station. 

 The first was carried on for twelve years in an old apple orchard in 

 which the trees had practically completed their growth before the 

 experiment began. The soil was a heavy clay loam, fairly typical of 

 the majority of the orchards of "Western New York. For twelve years, 

 applications of potassium, phosphoric acid and lime were made on an 

 orchard forty-three years old at the beginning of the experiment. There 

 were some slight gains in yield for the fertilized trees, but there were 

 no differences in color or keeping quality of fruit between crops from 

 fertilized and unfertilized trees. Practically, if not strictly in fact, the 

 results were negative. The data showed that it was not profitable to 

 apply potassium, phosphorus or lime to the soil of this Station orchard ;. 

 that fifty-five years of cropping had not reduced this soil to a condition 

 where it needs a '' complete" fertilizer. Stable manure or cover-crops 

 plowed under in this orchard showed beneficial results the same or the 

 next season. It would be an assumption to say which it is, the food or 

 the condition of the soil brought about by the organic matter, or both,, 

 that proved beneficial when manure and cover-crops were plowed imder. 

 The second experiment was with young apple trees ancl began in the 

 spring of 1896. Ben Davis stock set in April was top-worked to Rome 

 Beauty in July, the buds having all been taken from one tree to avoid 

 variations. The orchard was laid off in twelve plats of five trees each. 

 In plats 1 and 6 stable manure was used at the rate of five tons per acre ; 

 plats 2 and 8, acid phosphate at the rate of 350 pounds j^er acre; plats 

 6 and 10, acid phosphate and muriate of potash, 350 pounds of the 

 first and 200 pounds of the second ; plats 4 and 12, the above amounts 

 of acid phosphate and muriate of potash, plus 250 pounds dried blood 



