532 



SCIENCE 



[N. S. Vol. XXXII. No. 825 



pacity of the virgin soils, through unsani- 

 tary methods of handling the soil, the crop 

 and the seed. It may be a comparatively 

 new thought, but as I see it, there is no one 

 factor affecting cropping results to so great 

 loss of national wealth as the disease factor 

 in the soil, and no one feature of cereal 

 agriculture is so poorly understood and so 

 much neglected. It is becoming common to 

 term the farmer, and especially those who 

 are farming in a large way "soil robbers." 

 This is perhaps all right if we wish to 

 shock them so that they may take notice 

 while we call their attention to methods by 

 which, if they follow them they may better 

 their results and escape unjust criticism. 

 But not all such men are intentionally "soil 

 robbers." I have had the opportunity of 

 meeting many wheat raisers, cereal crop- 

 pers, who to my knowledge have more or 

 less constantly followed the best advice 

 available in cropping methods, at times 

 with success and at times with indifferent 

 success. Many are ignorantly soil spoilers 

 and "crop deteriorators. " It is to this 

 phase of crop deterioration by soil contam- 

 ination rather than to chemical depletion 

 that I wish to especially call attention. 



I recommend both our trained agricul- 

 turists and the farmer to look for help from 

 a careful consideration of soil sanitation 

 or, if you will, from proper conservation 

 of the purity of the soil. I consider it par- 

 ticularly important that this question 

 should be brought before this congress, for 

 this meeting is located at a point west of 

 the center of the last great virgin soil 

 areas of this country. And because, while 

 I recognize the great good that is done by 

 the advocates of the conservation of the 

 chemical qualities of the soil and still re- 

 main a strong advocate of the importance 

 of that feature, I feel that we have fol- 

 lowed it so persistently as to lose sight 

 of other features which have vitiated 



many of the conclusions which have been 

 drawn. When soil fertility is removed by 

 persistent or constant cropping there must 

 be some means provided for a reasonable 

 replacing of the same; and crop rotation, 

 as siieh, has been proved to be a matter 

 essential to cereal agriculture. I believe, 

 however, that the emphasis as to the cause 

 of the necessity of crop rotation has not 

 always been placed wholly in the right 

 place. We have paid too little attention to 

 physical or mechanical texture of the soil 

 and too slight attention to cultivation 

 methods as such, and no attention what- 

 ever to the sanitary condition of the soil. 

 We have continued to tell the farmer that 

 he must rotate because his methods of crop- 

 ping are removing the nitrogen, humus 

 and other essential features of the soil, ap- 

 parently forgetting, although we all know, 

 that a rotation is only another way of get- 

 ting more of these elements out of the 

 ground. We all agree in recommending 

 stock as essential, apparently forgetting, 

 although we all know, that that too is a 

 condensed manner of getting rid of the so- 

 called fertility of the soil. 



So, if it had not been for the biologist 

 demonstrating that the experience of many 

 farmers in replenishing soil nitrogen 

 through the vise of legumes is a fact of 

 plant life possible of intelligent control, 

 our theories of crop rotation would at this 

 time be in a sorry plight indeed, so far as 

 proving the worth of them from a chemical 

 standpoint alone. However, this problem 

 of the conservation of nitrogen is now a 

 settled one so far as common knowledge is 

 concerned, and even the question of the 

 conservation of the phosphates may rest in 

 nothing more than the problem of equi- 

 table distribution of the world's supply. 

 These fertilizers are based on substances 

 that can not well get away. Though fer- 

 tilizer experiments are as old as agricul- 



