OF WHAT VALUE IS IT? 35 



service to plants as sources of food. They 

 serve, moreover, as a culture-medium in 

 which nitrogen-fixing bacteria (azobacter 

 chrococcum, etc.) multiply rapidly. Hence 

 by adding cultures of nitrogen-fixers to steri- 

 lized humated peat, the amount of nitrogen 

 in the latter is increased. 



"It was to this large nitrogen content that 

 Professor Bottomley originally attributed 

 the fertilizing powers of bacterised peat. 

 Tests carried out at Kew on many different 

 kinds of greenhouse plants lillies, cyclamen, 

 coleus, primulas, etc. indicate in the most 

 striking manner that the addition of bacter- 

 ised peat to a potting compost brings about 

 a great increase of growth and vigor. The 

 amount of bacterised peat (or humogen, as 

 it is sometimes and somewhat inconsequent- 

 ly called) which produces these results is 

 about 10% of the total compost. 



"Those who take the trouble to reckon 

 what 10% means in tons per acre will recog- 

 nize that, unless far smaller dressings of 

 bacterised peat may be used, this fertilizer 

 cannot be applied with success to field crops. 

 Indeed, in certain field experiments which we 

 have witnessed the addition of dressings of 



