NATURAL ENVIRONMENT 55 



from distant points, and also paying duty on foreign varieties. 

 Then, too, injudicious seed exchange is a source of weed and 

 disease dissemination, as well as a powerful influence against 

 proper methods of plant breeding. Selection cannot be suc- 

 cessfully practiced in improving the quality of grain if the 

 seed must be given up every few years for a strain grown upon 

 other land. 



Nothing has been found in the principles of wheat de- 

 velopment which would indicate that wheat "runs out," or 

 deteriorates, if continually grown on the same farm under 

 rational methods of culture. Undoubtedly, any seed may de- 

 teriorate because of injuries arising from disease, improper 

 cultivation or selection of seed, or from many other causes 

 which militate against the production of a normal type of 

 kernel. Grass wheat formerly grown in Kansas is a case in 

 point. Experiments at different stations have shown that seed 

 may be sown on the same land for many years, and yet give no 

 appearance of running out. 1 



The idea that a change in seed gives good results has always 

 been founded more upon opinion than upon well ascertained 

 facts. It was doubtless first advanced by Columella shortly 

 after the Christian era, and has been widely held ever since. 

 The most striking argument in favor of the idea is put forth by 

 Darwin, who reasons that since a change of residence is of 

 undoubted benefit to convalescents, it may be that a change of 

 soil is advantageous for wheat. This is only reasoning by 

 analogy, however, and involves the comparison of abnormal 

 animal life with normal plant life, certainly not a strong argu- 

 ment at best. Some good authorities still hold that wheat will 

 run out if sown continually on the same land. 2 A great and 

 preponderating amount of evidence has accumulated, however, 

 to show that farmers should rely chiefly upon locally developed 

 seed, and that they should give more attention to the produc- 

 tion of their own seed. The importation of seed is profitable 

 only when differences in the rigors of soil and climate exist. 

 Such importations have greatly improved the standard of 

 American wheats and have also extended the industry of rais- 

 ing them. Foreign wheats are one of the most important fac- 



1 N. D. Bui. 17, p. 98. 



2 Saunders, Evidence 1903, p. 46; Kept. Kans. State Bel. Agr.. 

 Vol. 21, No, 81, p. 7. 



