316 EXPERIMEKT STATION RECORD. 



"As at present organized, this work is being conducted at the experiment sta- 

 tion, in Wayne County, where botli field and laboratory investigations are in 

 progress, and at the station's thi'ee test farms, viz, at Strongsville, Cuyahoga 

 County ; at Germantown, Montgomery County, and at Carpenter, Meigs County. 

 The worli on the farm of the State University was discontinued in 1900 ; that at 

 East Liverpool in 1901, and that at Neapolis, Fulton County, in 1902." 



The general plan of the experiments has been given in the abstracts of the pre- 

 vious reports referred to. 



Summarizing briefly the more important results which have been obtained up 

 to the present time, covering the 13 years, 1894 to 1906, inclusive, it was ob- 

 served that in 22 of the 24 separate comparisons the complete fertilizer produced 

 the largest total increase. In 16 of the 24 tests the combination of phosphorus 

 and nitrogen stood second in amount of increase produced. Of the 8 exceptions 

 in this case 5 were with crops occupying first place in the rotation crops — corn, 

 tobacco, and potatoes — grown on sod land. " In 14 cases the combination of 

 phosphorus and potassium occupies the third rank. In 2 cases it stands first, 4 

 cases second, and fourth in 3 cases and fifth in 1 crop. The fourth and 

 fifth places are nearly evenly divided between the plat receiving phosphorus 

 alone and that receiving potassium and nitrogen, so far as relative rank is 

 concerned. . . . 



" It is therefore evident that in all these tests, made upon soils widely dif- 

 ferent in origin, location, and previous history, and under varying systems of 

 cropping, from a 5-year rotation on an exhausted soil with but one clover crop in 

 each period and that usually a very poor one, to a 3-year rotation on rich land 

 on which good crops of clover were grown every third season, it has been the 

 complete fertilizer, carrying nitrogen as well as phosphorus and potassium, 

 which has produced the largest increase of crop. The clover crop alone, there- 

 fore, even under the most favorable natural conditions, and when abundantly 

 supplied with phosphorus and potassium, has not supplied sufiicient nitrogen to 

 maintain the maximum production of which the succeeding crops are capable. 



" It does not follow, however, that clover growing should be dispensed with, 

 or that the purchase of fertilizer nitrogen is recommended. On the contrary, 

 these experiments have shown that the increased gain resulting from the addi- 

 tion of nitrogen to the fertilizer is frequently insufticient to justify the pur- 

 chase of nitrogenous fertilizers at the present market rates, hence a cheaper 

 source of nitrogen must be found than nitrate of soda or the still more expensive 

 ' ammonia ' of the fertilizer sack, before we can profitably reach the maximum 

 production of our crops. 



" Fortunately, such a source lies within the reach of every farmer in the form 

 of barnyard manure." 



As a general outcome of this series of e.xi^eriments the author considers the 

 following points of fundamental importance in determining the fertilizer re- 

 quirements of a given crop : 



"(1) The geological history of the soil upon which the crop is to be grown. 



"(2) The system of cropping which is being followed and the place in that 

 system of that particular crop. 



"(3) The botanical relations of the crop itself, that is, whether it is classed 

 with leguminous or nonleguminous plants." 



A soil fertility test, G. A. Crosthwait (Idaho Sta. Bui. 59, pp. 16, figs. 5). — 

 This bulletin reports the results of greenhouse tests during 1906 in 4-gal. earth- 

 enware jars of typical virgin and cultivated Palouse soils. 



In the fertilized series of these soils nitrogen was supplied in the form of 

 dried blood, 15 gm. per jar; phosphorus as steamed bone meal, 6 gm. per jar; 



