176 
Management of Grass Land. 
* 
accumulated on or near the surface of the land. A warm July 
rain suddenly washes down to the roots of the plants an over- 
dose of manure, rich in ammoniacal salts, and the rank herbage 
so produced is unwholesome food. My first lesson, therefore, 
in manuring grass was that nitrogen, though most valuable in 
increasing the produce, and indispensable in restoring the con- 
dition, of exhausted land, cannot be used in large doses with- 
out materially diminishing the quality of the herbage. If called 
upon to explain this fact, I would suggest that plant-food to 
produce really healthy vegetation, should consist of a due admix- 
ture of several ingredients, of which ammonia, phosphoric acid, 
and potash, are most important. As the roots of plants can- 
not select the substances they require, but suck up all soluble 
matters with which they come in contact, if ammonia, which is 
extremely soluble, be presented to them in excess when com- 
pared with the other elements of their growth, the result is that sap 
is circulated through the plant of too stimulating character, and 
produces in the vegetable organisms results somewhat similar to 
those too often observed in the human subject who imbibes too 
much soluble matter of a stimulating kind : viz., high colour and 
vigorous vitality, but with a tendency to premature decay : in 
short, plants so treated are on the high-road to gout. If soils 
commonly contained a considerable amount of soluble phos- 
phoric acid and potash, a reasonably large dressing of ammonia 
would probably produce unmixed benefit, such as we see to 
result from a liberal application of manure from the yard, which 
supplies all these substances to the growing plant in the exact 
proportions required ; but, as the potash and phosphates con- 
tained in the soil itself are, for the most part, very slowly soluble, 
it is necessary to provide them in a more available form, in order 
to prevent ammonia from greatly predominating over the other 
ingredients, and thus injuring the quality of the produce. 
Next to nitrogen, the most important manurial substance is 
phosphoric acid, and, after being disappointed with the result of 
ammoniacal dressings, I made various trials of the phosphates in 
different combinations. The great success which attended the 
use of bones on the dahy-lands in Cheshire, and the ectperience 
of all observant shepherds that turnips, manured with bones, 
bore more hard weather, and were better sheep-meat, than more 
showy crops grown with other tillage, led me to anticipate great 
advantage from a lii)eral use of bones or superphosphate on grass. 
In this, however, 1 was again disappointed. Bones improved 
the quality of the pasture, and somewhat increased the proportion 
of clovers and fine grasses to the coarser kinds, but I could not 
satisfy myself that the improvement was sufficient to pay the bill. 
Lesson the second therefore taught me that bones alone could 
not be depended upon for the renovation of grass land in general. 
