24 EXPLOITATION OF PLANTS 
No apology is needed, I think, for describing these 
results in a lecture dealing with soil problems. Modern 
research has shown the intimate relationship between 
soil fertility and soil organic matter. For successful 
crop production the soil must be supplied with humus- 
forming material. Unfortunately, owing to the advent 
of motor traction, one important source of such material 
—stable manure—is rapidly diminishing. It has been 
stated that during the last few years the omnibus com- 
panies of London have dispensed with the use of 50,000 
horses. This represents a loss to suburban growers of 
250,000 to 500,000 tons of organic manure annually 
from this source alone. All over the country there is 
increasing difficulty in obtaining supplies of stable 
manure, and some substitute will have to be found. 
The experiments I have described point to the possi- 
bility of utilising peat as an organic fertiliser. Raw 
peat, owing to its acid nature and the toxic substances 
it contains, is not only useless, but actually injurious to 
plants. It has been shown above, however, that when 
peat is “‘ bacterised ” its condition is altered, and it 
then contains substances which have a remarkably 
beneficial effect upon plant growth. There are un- 
limited supplies of waste peat available in the United 
Kingdom, and if only a portion of these could be treated 
and rendered available as a cheap and effective plant 
food, it would greatly assist the successful exploitation 
of plants and benefit the whole community. 
