On the production of legume inoculants in a mixture of peat and soil

Summary

A study was made of the growth of rhizobia in mixtures of peat, heavy loam and CaCO₃, with or without addition of salts and of organic nutrients. Extremely high numbers (4000–20.000 millions per g of moist material) were obtained by using alder bog peat and 10–20% lucerne meal in these mixtures and by growing the rhizobia in pure condition with access of air. When lucerne meal is present in these quantities, addition of salts, yeast and other nutrients is superfluous. Good results have been obtained by using dispensing-bottles as containers, plugged with cotton-wool. The media in the bottles are inoculated with a liquid inoculum by means of a hollow needle, which is stuck between the cotton-wool plug and the wall of the neck of the bottle. By this simple procedure contamination of the media with air-borne organisms is reduced to a minimum. The numbers remain high for a long period when the cultures are stored at 2°C. with access of some air.