Apbil 15, 1904.] 



SCIENCE. 



621 



is not essentially difl'event from that in surround- 

 ing fields that have been under extensive cultiva- 

 tion. 



In England and in Scotland it is customary to 

 make an allowance to tenants giving up their 

 farms for the unused fertilizers applied in pre- 

 vious seasons. 



The basis of this is usually taken at 30 to 50 

 per cent, for the first year, and at 10 to 20 per 

 cent, for the second year after application, but 

 in the experience of this Bureau, there is no such 

 apparent continuous effect of fertilizers on the 

 chemical constitution of the soil* 



This quotation from Bulletin 22 is not re- 

 ferred to in Circular 72, but many other quo- 

 tations are made which show this same general 

 teaching and which Dr. Cameron now holds 

 ' are utterly at variance with the complete 

 context and plain meaning of the bulletin.' 

 Of course, the ' complete context ' can not be 

 quoted here, but, so far as I am able to judge, 

 this quotation, as well as all others which I 

 have made, are fair samples of the accepted 

 meaning of the bulletin as a whole. 



In this connection attention may well be 

 called to the fact that the above quotation is 

 quite out of harmony with the statement on 

 page 64 of Bulletin 22, to the effect that the 

 conclusions of the authors are ' strictly in 

 accord with the experience of good farm prac- 

 tise in all countries.' Probably there is no 

 better farming practised in any country than 

 in England and Scotland. After a full half 

 century of agricultural investigation at Roth- 

 amsted Sir Henry Gilbert says,t regarding 

 the effect of farm manure on certain plots of 

 ground : 



It has been seen that the unmanured plot has 

 declined in yield and fertility; but there can be 

 no doubt that the farmyard manure plot has, on 

 the other hand, increased in fertility. Analyses* 

 of the surface soil at different periods have 

 shown* that it has become about ttmce as rich in 

 nitrogen* as that of the unmanured plot. It has, 

 indeed, been shown that a large amount of the 

 constituents of farm manure accumulate ivithin 

 the soil* 



* Italicir'.ed by C. G. H. 



t U. S. Dept. Agr., Office of Expt. Stations, 

 Bull. 22, pages 149 and ISO. (This most valu- 

 able bulletin written by the late Sir Henry Gil- 

 bert, himself, giving results of fifty years' in- 

 vestigation at llothamsted, should be read by any 

 one who reads Bulletin 22 of the Bureau of Soils.) 



Again, Sir Henry says : 



Referring first to the results obtained on the 

 farm_yard manure plot, the average annual produce 

 over the [last] forty years was 347g bushels, and 

 over the fifty years 33% bushels; in the one 

 nearly 7 bushels and in the other 5V2 bushels 

 more than the average of the United Kingdom 

 under ordinary rotation; in both not far short 

 of three times the average produce of the United 

 States, and more than two and one half times 

 the average of the whole of the wheat lands of 

 the world. 



Without any manure whatever the average an- 

 nual produce was 13 bushels over the [last] forty 

 [years], and 1314 bushels over the fifty years. 



Dr. Cameron apparently admits, as shown 

 in Circular No. 72, that ' it has been possible 

 on the basis of chemical analysis to advise 

 the use of fertilizers containing potassium on 

 certain Illinois soils with improved yield of 

 crop,' but by the same system which he has 

 so successfully applied in using strictly se- 

 lected data from the llothamsted experiments, 

 he evidently overlooked the fact that on the 

 same page of Circular 72 is shown an equally 

 striking case where the chemical analysis of 

 other soils plainly shows the need of nitrogen, 

 the addition of nitrogen to these soils having 

 increased the yield of wheat more than eight 

 fold. 



Regarding the use of potassium, however. 

 Dr. Cameron adds : 



A soil containing according to analysis an 

 enormous amount of nitrogen (67,000 pounds per 

 acre), an abundant amount of phosphorus (2,000. 

 pounds per acre) but what is regarded as a 

 deficient amount of potassium (1,200 pounds per 

 acre) produced no corn* when either nitrogen or 

 phosphorus or both [or nothing] were applied; 

 yield about the same, 36 bushels when potassium* 

 40 bushels when potassium* and nitrogen or 38 

 bushels when potassium* and phosphorus were 

 applied. But when potassiitm* nitrogen and 

 phosphorus were all applied, the indications of 

 the analysis were flatly contradicted by a yield 

 of 60 bushels. 



This is, indeed, a most peculiar statement 

 both chemically and otherwise. The ' indica- 

 tions of the analysis,' instead of being ' flatly 

 contradicted by a yield of 60 bushels,' are 

 thereby confirmed, for if sufficient potassium 



* Italicized by C. G. H. 



