February 26, 1904.] 



SCIENCE. 



343 



for purposes of local assembly and fellowship, 

 but always witb the understanding that the 

 great meeting of the year should be with the 

 association, which shall shift about in its ses- 

 sions as heretofore. 



Thomas H. MACBEroE. 

 Iowa City, Ia. 



repIjY to AN" address: present status of soil 

 investigation. 

 Some criticism of Bulletin No. 22, U. S. 

 Department of Agriculture, has appeared re- 

 cently, the tenor of which is that the au- 

 thors of the bulletin have proposed new 

 chemical methods for the determination 

 of soil fertility, and that they have con- 

 cluded that the use of fertilizers is of no value 

 in affecting the yield of crops. These criti- 

 cisms have generally been copied from Cir- 

 cular No. 72, Agricultural Experiment Station, 

 University of Illinois, in which parts of sen- 

 tences from Bulletin No. 22 are brought to- 

 gether in an attempt to show a meaning which 

 they do not possess in their proper position. 

 The first paragraph of an ' Explanatory State- 

 ment ' prefixed to the Circular is as follows : 



This address was written for the purpose of 

 calling attention to certain discrepancies in the 

 work of the different prominent investigators in 

 the subject of soil fertility, especially such as 

 have a bearing upon investigations and conclu- 

 sions touching soil conditions in Illinois. The 

 paper deals particularly with the recently issued 

 and much advertised Bulletin No. 22, from the 

 Bureau of Soils, United States Department of 

 Agriculture, on ' The Chemistry of Soils as Re- 

 lated to Crop Production,' which says that ' prac- 

 tically all soils contain suflScient plant food for 

 good crop yields,' and that ' this supply will be 

 indefinitely maintained.' This is commonly un- 

 derstood and is certainly intended to mean that 

 the use of farm manure, the growing of clover 

 and other leguminous crops, as a source of nitro- 

 gen, or the application of bone meal or other 

 fertilizers has little or no tendency toward per- 

 manent soil improvement, and that even the effect 

 which they do produce is due very largely, if not 

 entirely, to improved physical condition of the 

 soil, which effect, the Bureau of Soils believes, 

 can be better obtained by ' a simple rotation and 

 change of cultural methods,' and the statement is 



added thai ' the effect due to cultivation is also 

 more permanent than the effect due to fertilizers.' 



As a matter of fact, these statements are 

 utterly at variance with the complete context 

 and plain meaning of the bulletin, but they 

 have been copied in the lay publications of 

 this country to such an extent as to call for 

 an explicit denial. That the authors of the 

 bulletin fully recognize the importance of the 

 proper use of fertilizers is made perfectly plain 

 by the following quotations (pp. 58 and 59) : 



There is no question that in certain cases, and 

 in many cases, the application of commercial 

 fertilizers is beneficial to the crop. The ex- 

 perience of farmers, the enormous sums expended 

 for commercial fertilizers, and the many experi- 

 ments carried on at the experiment stations prove 

 that under certain conditions fertilizers are very 

 beneficial in increasing the yield of crops. The 

 fundamental idea under all of this work, however, 

 has been that of supplying plant food in an avail- 

 able form; that is, adding to the supply existing 

 in the soil. It is significant that other conditions 

 of growth have so much influence on the yield that 

 in but very few instances, even after long-con- 

 tinued experiments, has it been demonstrated that 

 any particular fertilizer ingredient or ingredients 

 are required for any particular soil, and that even 

 then the effect of the fertilizer varies so greatly 

 from year to year that no specific law has been 

 worked out, even for a particular soil, from which 

 the fertilizing requirements could be deduced in 

 any exact manner. 



In cooperative experiments carried on by At- 

 water, numerous cases are cited where phosphoric 

 acid is said to be a regulating ingredient and the 

 predominating factor in controlling crop yields 

 one year, while it is more or less efiicient in the 

 same soil in other years, and is inefficient in 

 many cases in the same soils in still other years. 

 The same fact is brought out in regard to potash 

 and nitrogen, and it is clearly and unquestionably 

 demonstrated that the effect of fertilizers is de- 

 pendent upon the season, it being so influential in 

 one season as to be designated as a dominant 

 factor in the yield of the crop, while on the same 

 soil in a different season it has no apparent effect. 

 It is not that the effect is one year greater and 

 the next year less, which might be attributed to 

 the previous application, but it is just as likely 

 to be inefficient one year and the controlling 

 factor the next year as it is to be a controlling 

 factor one year and inefficient the succeeding year. 



