530 MISCELLANEOUS FARM SUBJECTS 



be transferred from one field to another by this means. In the sec- 

 ond method, a quantity of soil is moistened with large quantities of 

 culture, and this is mixed with more dry soil, and then used as a 

 top dressing on the land that is to be planted. For small gardens, 

 liquid cultures may be used and applied by means of a watering 

 can to the young plants, but it is far better to have the bacteria on 

 the seed so that the plant may become inoculated when they com- 

 mence to grow. The third method, seed treatment, consists in mois- 

 tening the seed with a culture or growth of the desirable bacteria, 

 allowing the seed to dry for a short time and immediately sowing it. 

 The latter is highly recommended. (Del. Col. B. 40; Y. B. 1909; 

 Ont. Agr. Dept, B. 148; Y. B. 1906.) 



Anyone who has seen the great injury wrought by root nema- 

 todes, the wilt diseases of melons, cowpeas, tobacco, cotton, tomatoes, 

 potatoes, flax, the black-rot of cabbage and cauliflower, the various 

 stem and root diseases of clover and alfalfa, and diseases of other 

 crops almost too numerous to mention, and widely distributed, will 

 investigate carefully before importing soil that may contain the 

 spores of these organisms. For the reasons above mentioned, pure- 

 culture inoculation must eventually mainly replace the soil-transfer 

 methods for all kinds of soil inoculation, but this has not yet been 

 put on a practical basis for any except the nodule bacteria. 



Artificial Cultures. A number of years ago a German inves- 

 tigator conceived the idea that inoculation might be brought about 

 by pure cultures grown in an artificial medium. Since that time 

 extensive experiments as to the value of this inoculation have been 

 conducted in all countries. 



A cheap and thoroughly effective way of distributing and ap- 

 plying these organisms in general agricultural practice has been de- 

 vised and put into use on a large scale. At a cost of a few cents a 

 bushel, the seeds of clover, alfalfa, peas, beans, or any other legumes 

 may be inoculated with these bacteria, thus making it possible to 

 secure good crops oir soils devoid of nitrogen, and at the same time 

 leave a large quantity of this element fixed in the soil in a form 

 available to wheat, corn, potatoes, or any other crop that may follow 

 the legumes. 



Since it is no longer questionable that the seeds of legumes can 

 be inoculated with artificial cultures of nitrogen-fixing bacteria and 

 large amounts of nitrogen gathered from the air and converted into 

 forms, not only available for the growing crop but stored in the 

 land for the use of future crops, it would be well to note the con- 

 ditions under which the best results may be obtained. (1) On poor 

 land that has not previously grown legumes; (2) on land that pro- 

 duces poor crops of legumes and where, upon examination, the 

 roots fail to show the presence of nodules; (3) where the legume 

 to be planted is of a widely different species to the ones previously 

 planted on the land; (4) where the land has previously produced a 

 lot of legumes, possessing nodules which, instead of being beneficial, 

 acted as parasites. Good results may be obtained from the use of 

 pure cultures when a field which has previously grown good crops 



