92 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
Professor Middleton, and included some interesting results in 
connection with the formation and improvement of pastures, and 
a species of disease-resisting wheat was shown. 
The Royal Agricultural Society had a large exhibit, that 
from the Experimental Station shown by Dr Voelcker, and 
ably explained by his assistant, Mr H. M. Freear, being the 
most important portion for the forester. There was a very 
instructive set of pot cultures and diagrams; but perhaps the 
most instructive was an exhibit demonstrating the influence 
on wheat of soils of lime and magnesia in varying relative 
proportions. There was also an interesting exhibit showing 
the influence of lime in improving turf. It often happens that 
when planting is done on old pasture, and more especially on 
waste land, there is a spongy layer of half-dead grass immedi- 
ately above the soil, which has a harmful effect on the young 
trees. If we use a fairly large-sized plant, say a 2-year 2-year 
Scots pine, it is not only partially buried, but this spongy layer 
prevents rain and moisture from reaching its roots. If, on 
the other hand, we use say 2-year 1-year Scots pine, 
and do the work thoroughly, it becomes necessary to remove 
a sod prior to planting the seedling. Hence both methods 
involve considerable expense, and court a proportion of failures. 
The spongy layer is acid in reaction, and contains nitrogenous 
matter derived from the decayed plant residues of which it 
is composed. The nitrogenous matter, however, is not directly 
available as a plant-food, but must first be converted into a 
soluble and available form by the action of the nitrifying 
organisms always present in fertile soil. When the soil is 
acid, the nitrifying organisms are unable to do their work; 
hence lime is applied to neutralise the acidity of the 
soil, and thus gradually to allow the nitrogenous matter to 
become converted into a soluble and available form. By the 
use of lime, then, the agriculturist causes the useless layer to 
disappear and the grass to improve; and the arboriculturist 
may do the same by the use of slag (which contains lime as 
well as phosphoric acid)’on land of a clayey nature, and slag 
and kainit on poor soil, together with severe pasturing by cattle 
and sheep prior to planting. It is open to question whether, 
from a manurial point of view, the slag improves the young 
trees, but undoubtedly it improves the pasture, inducing the 
stock to eat the herbage closer, and therefore subsequent planting 
