ALTERNATIVE METHOD 317 



Dr. C. B. Lipman gives the following method for inoculating 

 beans, and in a modified form it can be used for other legumes : 



"Method Involving the Use of One Commercial Culture. Prepare 

 one-half barrel full of good loam soil (150 pounds) with sufficient 

 water to make about optimum moisture conditions. This soil can 

 be kept in a shallow vat about a foot in depth or in some other 

 convenient receptacle where it can be well aerated. Purchase one 

 commercial culture from any of the commercial firms selling legume 

 bacterial cultures, choosing a culture for beans of the variety desired. 

 The amount usually sold in a culture for one acre is sufficient. 

 Shake this up with a few quarts of boiled water. The shaking should 

 be continued for about ten minutes to get all the bacteria in sus- 

 pension. Pour this suspension all over the surface of the soil in the 

 vat and add to the solution about one-quarter of a pound of ordinary 

 sugar per one hundred pounds of soil used in the vat. This should 

 be distributed as evenly as possible through the soil and the latter 

 thoroughly mixed with a spade or hoe, thus distributing both the 

 sugar solution and the culture. After that the inoculated soil is to 

 be kept in a warm place like a kitchen or a warm stable and the 

 moisture content maintained at optimum until you are ready to use 

 it for the inoculation of beans when they are planted. It is well to 

 allow a period of two or three months for such incubation. 



"At the end of the incubation period or when getting ready to 

 plant, shake up some of the inoculated soil with clean water for 

 a few minutes as before to get a good suspension of the bacteria. 

 Pour enough of this suspension over the bean seed in large tanks 

 or similar receptacles to wet the seed thoroughly, but not enough 

 to allow any excess of water. Then spread the bean seed out on a 

 canvas in a thin layer in the shade. As soon as the seed is air-dry and 

 will not stick, place in a planter and plant immediately. In cases 

 in which only small quantities of seed are to be planted, the suspen- 

 sion need not be made, but the inoculated soil in small quantities 

 can be mixed with the seed in the planter and allowed to drop with 

 the beans as they are dropped from the machine, thus introducing 

 the bacteria into the soil with every seed, or nearly so. 



"Alternative Method. Where it is not desired even to purchase 

 one commercial culture, inoculation can also be carried out entirely 

 successfully by obtaining soil from a garden in which beans have 

 grown successfully for some years and using that ,soil for making up 

 the soil suspension or for mixing with the seed as above described. 

 In other words, this garden soil, which contains the necessary bac- 

 teria, will serve fully as well as the inoculated and incubated soil 

 just described above. This is of course the simpler method to those 

 who have access to garden soil which has produced beans successfully. 

 Soils like this may also be obtained from old and more extensive 

 bean fields, where successful bean-growing has been carried out. 



