1906.] 



Inoculation of Leguminous Plants. 



645 



Cambridge. — Moore's culture : good garden soil, partly steril- 

 ised by repeated exposure to steam at 212 deg. F. No increase 

 produced by inoculation, nor were any nodules formed on the 

 roots of the plants either with or without infection. The extract 

 from a good garden soil also tailed to produce nodules. The 

 tests were carried out in duplicate. 



Chelmsford. — Moore's cultures for beans, peas, and clover : 

 good results were obtained by the inoculation of sterilised and 

 unsterilised sand, but no difference was obtained by the inocula- 

 tion of sterilised soil. 



Kingston. — Moore's and Hiltner's cultures for peas, beans, 

 clover, and vetches : sand and soil sterilised in the pots in an 

 autoclave at 120-130 deg. C. for about one hour each. With 

 each crop the soil and the sand were inoculated, inoculated seeds 

 also were sown in soil and sand, results were compared with 

 uninoculated pots and with uninoculated pots manured with 

 combined nitrogen, and in the case of clover and vetches, with 

 pots inoculated with crushed healthy nodules. All pots were 

 manured with a dilute manurial solution containing all the 

 elements of plant food, with the exception of combined nitrogen. 

 Combined nitrogen was added to one set of uninoculated pots. 

 Pure, almost sterile, distilled water was used throughout the 

 experiments. The plants were kept in trucks in a greenhouse 

 built for the purpose of experiments on nitrogen assimilation, 

 with a grant from the Royal Society. When fine, they were run 

 into the open garden during the day. 



The results were as follows : — In the pots of sterilised soil, the 

 yield of the pots containing combined nitrogen was little better 

 than that of the uninoculated pots without nitrogen, showing 

 that the soil in the latter contained almost enough nitrogen. 

 The increase in the air-dried crops only amounted to 2'6 grams 

 in the case of the beans and peas, this being 6'5 and 104. per 

 cent, increase in each case. The inoculation with either culture 

 failed to produce any increase over the uninoculated pots, the 

 yields of total air-dried crop being less in every case. A few 

 nodules were, however, produced with Hiltner's cultures. 



Much more marked were the results obtained in sterile sand, 

 the peas (see Fig. 3), vetches and red clover all showing similar 

 results. 



