396 ANNUAL REPORT OF THE Off. Doc. 



begin my speech. But there is just one thing that I want to say; 

 those of us who have been working in our little corner up there have 

 been a:<tounded and gi'atified at the moral support and backing that 

 has been given us in our efforts to raise the agricultural standards 

 of the State of Pennsylvania. We know that we have received the 

 moral su})port of the farmers and citizens of Pennsylvania and I feel 

 assured that we will continue to receive it, until our School of Agri- 

 culture and Experiment Station are equal to any similar institution 

 in the United States. 



Dr. Hunt's paper is as follows: 



SOIL FERTILITY. 



By DR. THOMAS F. HUNT, State College, Pa_ 



The Pennsylvania Agricultural Experiment Station has the long- 

 est continuous scries of fertilizer experiments in America. It is my 

 purpose in the forty minutes at our disposal to tell you of the more 

 important results obtained during the first twenty-five 3'ears. This 

 plats each in a rotation consisting of corn, oats, wheat and hay. The 

 series of fertilizer experiments was conducted on four tiers of 36 

 hay was a mixture of timothy and clover. A complete rotation of 

 crops is raised each jear; in other words, each year there has been 36 

 plats of ear corn, corn stover, oat grain, oat straw, wheat grain, 

 wheat straw and hay. During tvrenty-five years therefore, 630U sepa- 

 rate weights have been taken. This vast accumulation of results co ve- 

 ering a quarter of a century of continuous experimentation has been 

 used in arriving at the statements presently to be made. No attempt 

 will be made to discuss the data at length but only to point out the 

 most salient facts. A. D. Hall, refering to the plat experiments of 

 the Rothamstead station in England, which have been in progress 

 sixty or more years, recently stated that had the experiments ter- 

 minated at the end of forty years they would not have been able to 

 give their present interpretation to the results. With this illustra- 

 tion before us it is not wise to attempt too wide or too positive 

 generalizations from the results of twenty-five years of field ex- 

 periments. 



Before taking up the results of this series of experiments, it may 

 be well to emphysize what all practical farmers know to be true, 

 namely, that the best results and, generally speaking, profitable re- 

 sults can be obtained with fertilizers only when other conditions are 

 favorable. The essentials of plant growth are light, heat, soil mois- 

 ture, soil air, plant food and the absence of any unfavorable or un- 

 healthy condition of soil, such as too great an acidity of alkalinity 

 of the soil. If through natural conditions the land is water soaked, 

 thus reducing the temperature and excluding the soil air, the addi- 

 tion of fertilizers can be of no practical value. If from lack of till- 

 age a suitable seed bed is not obtained and proper environment main- 

 tained for the roots profitable crops need not be expect<^d. There 

 is nothing plainer than that profitable returns cannot be obtained 

 unless by proper tillage and decaying vegetable matter we maintain 

 suitable conditions for the growth of organisms which add nitro- 



