480 



SCIENCE 



[N. S. Vol. XXXVIII. No. 979 



permanent cropping element of old land agricul- 

 ture, but rather, instead, are reaping lessened 

 yields of poorer quality from larger acreages. 



In eolumna one and twenty the " new basis " 

 is revealed: 



Deteriorated wheat, as seen in depressed yields 

 and low quality, as now quite commonly produced 

 in the great natural wheat-producing regions of 

 this country, is not, primarily, a matter of lost 

 fertility or of modified chemical content of the 

 soil, but is specifically a problem of infectious 

 disease which is superimposed upon the problems 

 of soil and crop management. 



My experience with cereal crops with reference 

 to the application of fertilizers, the trial of 

 varieties, experiments in seed selection, seed breed- 

 ing and seed treatment, and seed purification fur- 

 nish data which will allow me to say that I have 

 no fear that all will eventually agree that sanitary 

 considerations with reference to the characteristics 

 of parasitic diseases which are now quite com- 

 monly resident in the seed and the soil will yet 

 form the essential basis for the proper manage- 

 ment of crops in rotation in series, and the same 

 considerations will largely govern the type of till- 

 age and the manner of handling waste materials 

 on the farm, particularly farm manures. 



Professor Bolley heartily commends him- 

 self for " having grown up on the farm, and 

 never having allowed himself to get away 

 from the real love of working in the dirt " ; 

 but he fears that " too many of our workers 

 who are paid to investigate agricultural prob- 

 lems may only investigate for their ovsm en- 

 joyment — may again deal in formulas, and 

 theories, books and philosophies, and thus give 

 out to the working public fine philosophies 

 which may yet leave the worker helplessly in 

 the dark as to what to do." 



As an average of sixty years where wheat 

 has been grown year after year on the same 

 land at Rpthamsted, the unfertilized land pro- 

 duced 12.6 bushels per acre, while 35.4 and 

 37.0 bushels were the respective yields where 

 farm manure and commercial plant food were 

 applied. 



As an average of twenty-four years the 

 wheat yields at Pennsylvania State College 

 varied from 10.1 bushels on unfertilized land 

 to 24.1 with farm manure and 24.8 with com- 



mercial plant food, when grown in a four-year 

 rotation. 



As an average of nineteen years the wheat 

 yields at the Ohio Experiment Station were 

 10.2 bushels on unfertilized land, 21.7 bushels 

 with farm manure, and 26.9 bushels where 

 commercial plant food was applied, the wheat 

 being grown in a five-year rotation with 

 clover, timothy, corn and oats, on five different 

 series of plots, so that every crop might be 

 represented every year. 



As compared with Eothamsted, Pennsyl- 

 vania and Ohio, the more extensive and very 

 practical field experiments now being con- 

 ducted by the University of Illinois in many 

 different parts of the state are new and incon- 

 clusive, but the results secured in 1913 from 

 fields that have been in operation twelve years 

 (see the accompanying tabular statement) not 

 only represent much field work, but they also 

 support the equally valuable analytical data 

 from the chemical laboratory involving an- 

 alyses of thousands of representative soil 

 samples collected in connection with the detail 

 soil survey of more than forty counties. 



1913 Wheat Yields: Bushels per Acre 

 From University of Illinois Experiment Fields 



The unfertilized surface soil of these fields 

 contains in two million pounds (correspond- 

 ing to an acre of land about 61 inches deep) 

 from 700 to 1,200 pounds of total phosphorus 

 and from 25,000 to 36,000 pounds of total 

 potassium. Where organic manures are pro- 



