Journal of Agriculture. [lo Feb., 1910. 



TESTS WITH CULTURES OF ROOT-TUBERCLE 

 BACTERIA. 



Alfred J. Eivart, D.Sc., Ph.D., F.L.S., Government Botanist and 

 Professor of Botany in the Melbourne University. 



Since the article on this subject was published in the January 1909 

 number of the Journal, a series of tests have been carried out at the 

 Burnley Horticultural Gardens and at the University, with a view to 

 investigating the practical utility of cultures of root tubercle bacteria, such 

 as are sold under the names of " Nitragin," " Nitro-culture," &c. 



The necessity for such tests is clearly shown by the remarkably 

 divergent results obtained in different countries and in the same country 

 by different investigators, as well as by the fact that recently pamphlets 

 have been widely distributed in this State making various extravagant or 

 untrue claims on behalf of these cultures. It is claimed, for instance, 

 that the cultures benefit the growth of leguminous plants (peas, beans, 

 lucerne, lupins, clover, &c.) on all soils, and that they may be directly 

 used to improve the growth of cereals (barley, wheat, oats, &c.). The 

 latter statement, in particular, is quite untrue. Cereals have no tubercles 

 on their roots ; they do not assimilate the free nitrogen of the air, and 

 therefore cannot possilily be directly benefited by inoculation by root- 

 tubercle bacteria. Any person led by such a statement to purchase 

 bacterial cultures for inoculating a cereal crop, would have just cause for 

 a legal action against the agent or company responsible for obtaining his 

 money bv false pretences. The jx)int cannot be too strongly emphasized 

 that even if the cultures of root-tubercle bacteria did all that was claimed 

 for them, they could only l>e expected to benefit leguminous crops' grown 

 in soils in which root-tubercle bacteria are deficient or absent, and there 

 are other and more efficient ways of adding bacteria to .such soils than 

 by the use of exj>ensive and uncertain cultures'. 



It cannot be denied that, in the hands of various scientific experi- 

 menters at different research stations in Germans , the proper use of the 

 cultures' has enabled particular leguminous crops (lupins, peas, &c.) to 

 grow well in soils where, owing to the deficiency of the appropriate root- 

 nodule bacteria, growth was otherwise deficient or very poor. At the 

 Tharand Experiment Station, the relative merits of commercial prepara- 

 iions of root-tubercle bacteria, such as Nitragin, Nitro-culture, &c., have 

 been investigated. Experiments have been also conducted in Scotland. 

 In some cases, the crops were apparently benefited, but in others their use 

 appeared to be inimical to the crop instead of advantageous. This .was 

 possibly due to the experiments having been tried on land in which the 

 requisite root-tubercle bacteria were already abmidantly present, and to 

 the fart tliat the treatment of the seeds before planting may in some cases 

 weaken their germinative power ; or it may have been due to insufficient 

 attention being paid to the unavoidable fluctuations occurring in all field 

 experiments. 



The German results are, however, more uniformly favourable, possibly 

 owing to the more judicious use of the cultures and the restriction of the 

 experiments to soils where good results were likely to be obtained. 

 Vogel, for instance, in the Illustrierte HandieirthscJiaftlchc Zeitung for 

 1907, page 5, sums up generally in favour of the improved Hiltner 

 cultures for practical use with the improved methods of inoculation. For 

 instance, out of 62 tests of pure cultures for Serradella, 85 per cent, gave 



