142 EXPERIMENTAL FARMS. 



The next step, also taken by Dr. Nobbe, was in the isolation of the nitrogen-con- 

 verting microbes from such soil and the preparation, by certain well known 

 bacteriological methods of "pure cultures." These cultures consist of colonies of the 

 organisms and the preparation has been named Nit7-agin. 



It would appear that the members of the leguminosse have each their own peculiar 

 bacterium or micro-organism, for it seems that those influencing the assimilation 

 of nitrogen in the clover plant are of no value for the pea crop, and vice versa. Hence, 

 the necessity for the preparation of clover " nitragin," pea "nitragin," &c. These cul- 

 tures or bacterial preparations, to the number of 17, are now manufactured on a 

 commercial scale in Germany, and a quantity of each said to be sufficient to inoculate 

 an acre can be procured for about $1.25. 



The practical application of Nitragin has been made in two ways ; first, by diluting 

 the preparation with sufiicient water and sprinkling the seed with the fluid, and, 

 secondly, by treating a quantity of soil with a dilute solution of the preparation, 

 allowing the soil to dry, and then spreading it evenly over the field to be inoculated, 

 which is then deeply harrowed. 



Following these methods, experiments have been made in Germany, England and 

 on this continent. The results so far obtained, as gathered from the reports of these 

 investigations, scarcely admit of any more emphatic statement than that the indications 

 are that on soils that have not previously grown legumes, or for other reasons do not 

 contain the nitrogen-assimilating bacteria, the practice of inoculation will be attended 

 with profit. Some soils contain such an abundance of these microbes that a further 

 supply is unnecessary. European field experiments seem to show that even when the 

 growth of the foliage is not increased by Nitragin there is frequently a greater root 

 development and a larger number of nodules. No great difference could be noted, in 

 these reports, between the results of soil inoculation and seed inoculation, though such 

 differences as there are appear to be in favour of the former. 



EXPERIMENTS WITH NITRAGIN. 



In the spring of the present year we obtained from Messrs. Meister, Lucius and 

 Bruning, Hochst am Main, manufacturers of bacterial cultures, Nitragins, for alfalfa or 

 lucerne, clover, horse beans and vetch. The soil used in our experiments was made 

 from clay, sand and swamp muck and would be termed a loam of medium fertility. It 

 was not sterilized, in order that the conditions might be comparable, as far as possible, 

 to those on the farm. The experiments were conducted in duplicate in galvanized iron 

 pots and the methods of inoculation above described were employed, check, or uninoc- 

 ulated, pots being sown at the same time. After the plants had reached the height of 

 a few inches they were thinned out to the same number in each pot. The seed in all 

 the trials was sown on May 20th, 1897, the plants of the clover, alfalfa and vetch 

 showing above ground in all the pots on May 25th, and the horse beans on May 31st. 

 The soil and seed of the inoculated tests were treated with the respective Nitragins on 

 the day of sowing, May 20th. 



Unfortunately, the growth of the alfalfa and vetch was very meagre and it was, 

 therefore, deemed inadvisable to weigh and analyse their crop, as the results might be 

 misleading. 



INOCULATION EXPERIMENTS WITH HORSE BEANS (PABA VULGARIS, var. EQUINA). 



(Sown 20th May, collected 4th August, 1897.) 



The plants were thinned out to five (5) in each pot. On August 4th, the plants 

 being then in pod, the experiment was brought to a close. The difference in foliage 

 in the various pots was not very marked, though the plants in the pots containing thr- 

 inoculated soil (H.H.) were decidedly larger and more robust than the others. In all 

 the pots the plants appeared healthy. 



