CONTRIBUTIONS FROM THE WISLEY LABORATORY. 175 
CONTRIBUTIONS FROM THE WISLEY LABORATORY. 
XL. — Experiments on Green Manuring for Light Soils. 
By H. J. Page, M.B.E., B.Sc, A.I.C. 
The growing scarcity of animal manure is a matter which most 
directly concerns the horticulturist. Keeping no stock himself, the 
gardener has to obtain his manure from outside sources. These 
sources are twofold : the farm and the town stables. The first 
source is failing ; more land under the plough on the one hand, 
and a diminished number of stock on the other, combine to reduce 
very considerably the surplus of farmyard manure which the farmer 
has to sell after supplying his own needs. The alternative source, 
the town stables, which formerly supplied a large proportion of the 
horticulturist's needs, is also rapidly failing, for, in the face of the 
increasing use of motor transport, the horse is disappearing from 
the roads. Although the point has not yet been reached where 
the amount of animal manure available to the horticulturist (taking 
the country as a whole) is negligible, yet the relation of the demand 
to the supply is shown in a very great, and in some cases almost pro- 
hibitive, increase in the price of dung. Moreover, the position is 
likely to become steadily worse as time goes on. Further, the gar- 
dening and agricultural industries are not evenly distributed over 
the country, so that although in some districts there may still be 
enough cheap farmyard manure, in others it has always been scarce, 
and is now almost unobtainable except at the cost of heavy freight 
charges. 
For the proper maintenance of its fertility the soil must be well 
supplied with organic matter. The intensive methods of cultivation 
practised by the horticulturist are specially exhausting to the soil, 
so that while he is the first affected by the growing scarcity of dung, 
he is more in need of it than any other cultivator. It is, therefore, 
a matter of the utmost importance to provide some other source 
of organic matter. Supplies from many of the alternative sources 
that suggest themselves are either too scarce and expensive, or only 
available in special districts (e.g. seaweed). Others which may later 
become of great importance are " artificial farmyard manure " (straw 
manure) and activated sewage sludge. There remains, however, a 
method of supplying organic matter to the soil which is capable of 
almost universal application, and which has been known since the 
earliest times — namely, green manuring. 
Hitherto green manuring has not been widely practised in this 
country ; this is no doubt partly due to the fact that, in general, 
dung was until recently relatively plentiful, so that the need for an 
alternative source of organic manure did not generally arise ; but 
