42 



THE IRRIGATION AGE. 



securing a very thin stand. It is best, therefore, to 

 plant alfalfa on a tract of land that is as free from 

 weeds as possible. Land that has been summer- 

 fallowed the previous year, or that has produced 

 potatoes or other rowed crops is best adapted for 

 alfalfa, as it will be the freest from weeds. Grain 

 land that is fairly free from weeds is also well 

 adapted for alfalfa, provided it has been in cultiva- 

 tion long enough to disintegrate the sod. Do not 

 plant alfalfa on new breaking, as the prairie and 

 other grasses will not let the alfalfa secure a good 

 quick start. 



Inoculation 



As was mentioned in the introduction, alfalfa 

 has the power of supplying nitrogen to the soil, and 

 it is a good thing Providence provided this plant 

 with this power, for if it did not have it there would 

 be but few soils sufficiently rich in nitrogen to grow 

 the crop for any length of time. This same thing 

 would probably hold true to a somewhat lesser ex- 

 tent with the other leguminous crops, for they all 

 contain a large amount of nitrogen or protein. They, 

 therefore, must be able to secure a large amount of 

 it from the soil. The manner in which alfalfa and 

 the other legumes supply nitrogen to the soil is 

 through the bacteria which live in and upon their 

 roots. These bacteria are not originally present in 

 all soils, for these particular bacteria cannot live 

 without legumes, nor can the legumes live for any 

 length of time without the bacteria, the principal 

 reason being that the legume is such a greedy feeder 

 upon the nitrogen in the soil that unless the bacteria 

 are present, it soon exhausts the available nitrogen 

 in almost any soil. While all legumes harbour bac- 

 teria of much the same nature, it has been found 

 that there are certain kinds that prefer each par- 

 ticular leguminous plant. This is probably due to 

 the fact that these particular bacteria have adapted 

 themselves to this plant. These bacteria are so 

 small that they can scarcely be seen with even a 

 microscope of the highest power. It is believed that 

 they are absorbed by the minute root hairs along 

 with the water, and after being absorbed irritate the 

 roots to such an extent that plant juices are auto- 

 matically thrown out at the spot, thus forming the 

 little appendages called nodules in which the bacteria 

 live. These nodules vary with alfalfa from small 

 whitish lobes the size of a pin head to clusters of 

 these lobes one-half inch in diameter arranged some- 

 what like a bunch of grapes. These bacteria after 

 becoming domiciled in the nodules attached to the 

 roots multiply at an extremely rapid rate, and are 

 able to absorb the free nitrogen found in the air 

 spaces of the soil, and work it over into nitrates, a 

 definite chemical compound and a plant food of the 

 highest value, in which shape the alfalfa itself or any 

 other plant can utilize it. These bacteria, therefore, 

 are very essential to alfalfa, no matter where it is 

 grown. In the soils of certain districts throughout 

 the west it seems there are enough of these alfalfa 

 bacteria or other bacteria of a similar nature that can 

 readily adapt themselves to the alfalfa plant, so that 

 it is unnecessary to inoculate the alfalfa at the time 

 of planting. Such is not the case here, however, 

 though the continued planting of alfalfa on our irri- 

 gation projects may in time develop these bacteria 

 so that they will become so widely scattered 



throughout the soil that it will be found unnecessary 

 to supply them artificially. 



The best method found to date of supplying 

 these bacteria to our alfalfa fields is to secure surface 

 soil to a depth of nine or twelve inches from an old, 

 well-established alfalfa field that has become well 

 inoculated, and to scatter this soil evenly at the rate 

 of from 200 to 400 pounds per acre upon the field 

 after it has been prepared for alfalfa, and immedi- 

 ately before seeding. Failure to do this and take 

 the proper precautions after it has been done has 

 probably been the cause of a greater number of fail- 

 ures with alfalfa in this part of Alberta than all other 

 causes taken together. These bacteria can stand 

 very low temperatures, even 20 or 30 degrees below 

 zero will not kill them, but either bright sunlight 

 for a few moments or a continued temperature for a 

 few hours of 100 or more degrees Fahrenheit will 

 kill them very readily. It is, therefore, very neces- 

 sary to secure the original soil in a fresh condition, 

 to keep it in a comparatively cool place free from 

 sunlight and to spread it promptly and evenly upon 

 the field to be planted, after which it should be im- 

 mediately harrowed in so as to cover the bacteria 

 deep enough and quick enough so that they cannot 

 be killed by sunlight. If these precautions are 

 taken, but little trouble will be experienced with the 

 soil transfer method of inoculation. 



There is one other method of inoculation that is 

 coming into quite general use. This is inoculation 

 by pure cultures, which are purchased from labora- 

 tories which make a business of growing and pre- 

 paring these cultures for this use. These cultures 

 cost from one to five dollars per acre, are put up by 

 the laboratories, and delivered to the consumer in 

 small bottles, each bottle containing millions of the 

 proper kind of bacteria. The directions for using 

 these cultures differ slightly, but should be strictly 

 followed. They usually state that the contents of 

 the bottle should be emptied into a gallon of water 

 that has previously been boiled and cooled, to which 

 is added a little sugar or beef broth, after which the 

 mixture is placed for forty-eight hours in a mod- 

 erately warm place to enable the bacteria to grow 

 and multiply, about the same as a house-wife sets 

 her yeast. After these bacteria have been developed 

 a little more water is added, after which the alfalfa 

 seed itself is thoroughly sprinkled with the solution 

 containing the bacteria. The seeds are then allowed 

 to dry in a moderately cool, dark place, after which 

 they should be immediately planted. If the culture 

 is good when secured and directions are followed 

 out, a sufficient number of bacteria are usually at- 

 tached to the alfalfa seed to thoroughly inoculate 

 the whole field. After the small plants start to 

 grow the bacteria are absorbed by the roots, and the 

 process previously described is carried out, the bac- 

 teria not only furnishing sufficient nitrogen in an 

 available form for the growth of the plant, but an 

 excess supply for the crops which will follow, after 

 the alfalfa is plowed up. 



The soil transfer method of inoculation where 

 soil free from weeds can be secured is, however, 

 probably the cheapest, surest and best method for 

 the farmers of this section, and if directions are care- 

 fully carried .out there will be but few failures. The 

 principal precautions that are necessary are (1) to 



