28 MAINE; AGRICULTURAlv EXPERIMENT STATION. I906. 



58 pounds potash that it will cost more than $18 to replace 

 commercially. 



The plan of a hay farm does not admit of rotation of crops. 

 Rotations are very important in the proper and economical hand- 

 ling of land. For instance, if potatoes or corn are grown 

 preceding grass, the land will be in equally good condition from 

 fall plowing and once harrowing in the spring as from the 

 frequent harrowings necessitated by summer seeding. In the 

 rotation most of the cost of the preparation of the seed bed falls 

 upon a money crop as potatoes, or corn, and not upon the next 

 season's grass crop. 



The seeding formula recommended by Mr. Clark does not 

 contain clover. This is the most important forage plant that the 

 Maine farmer can grow. It is rich in protein and is able to 

 obtain its nitrogen from the air. While clover hay does not 

 command as good price as that from red top and timothy, it can 

 be grown at a less cost per ton and has a greater feeding value. 



Soil Inoculation for Legumes erom Artieiciae Cultures 

 BY THE Help oe Bacteria. 

 That legumes such as peas, clover, etc., can by the help of 

 bacteria acquire atmospheric nitrogen through their roots has 

 been a matter of common knowledge for 20 years. The bacteria 

 produce enlargements upon the roots of the plants, which are 

 called root nodules. Not all soils carry the proper organisms, 

 but those deficient can be artificially inoculated. About ten years 

 ago, under the name of Nitragin, commercial cultures were 

 prepared in Germany for the purpose of inoculating sterile soils. 

 This matter is discussed in considerable detail, together with 

 certain experiments with nitragin, in the reports of this Station 

 for 1897, 1898 and 1900. As a scientific curiosity nitragin was 

 of great interest, but in practice it oftener failed to yield satis- 

 factory results than to give them. The principles underlying the 

 use of nitragin are of great practical importance, and many 

 investigators are at work upon the problem. It was announced 

 in an almost sensational article in the Century Magazine for 

 October, 1904, that the U. S. Department of Agriculture had 

 solved the problem of preparing active cultures in a convenient 

 form for distribution. Later the department issued a bulletin * 



* Bui. 71, Bureau of Plant Industry, U. S. Dept. Agr. 



