214 
Experiments with Guano, and other Manures. 
plots — the rapid growth and early vigour of the one, with its com- 
plete cessation at a certain period, and the continued increase and 
actual revival of the other at a late stage — it seems reasonable to 
conjecture that guano gives off its ammonia too rapidly to supply 
and stimulate the plant for a sufficient length of time to bring it 
to maturity, and that the reverse is the case with farm-yard 
manure ; and, therefore, that guano is best applied as a stimulant 
in the first stages of growth, but that it ought to be accompanied 
with some other manure whose effects are more lasting. This 
conclusion is borne out by the result of Mr. Jobling's judicious 
experiments (Nos. 1 and 2), where it is seen that the turnips from 
an acre which had 10 loads of dung, and 100 lbs. of guano, 
weighed one-third more than those from an adjoining acre with 
20 loads of dung. The land on which this experiment was tried, 
although by draining and subsoil-ploughing it has been made to 
grow good turnips, is rather of a stronger quality than what is 
commonly designated as turnip land, and on which the growth of 
the turnip plant is generally slow until it gets hold of the manure; 
but in this case I doubt not that it was rapid from the first — the 
guano supplying its early nourishment, and being succeeded by 
the more lasting effects of the farm-yard manure, it was carried 
forward without a check throughout, and maintained a decided 
superiority to the end. Its failure, too, when applied to wheat 
(Nos. 19 and 20), a crop which requires support for so many 
months, is another proof of its want of durability. We may learn, 
too, from these experiments, inconclusive and unsatisfactory as 
they undoubtedly are, that anything compounded and sold under 
the name of " artificial guano " should be adopted with great 
caution (see No. 14) ; and that none of the newly-introduced 
manures, however beneficial they may prove in peculiar soils and 
situations, are so generally certain and lasting in their effects as 
the common manure of the farm ; and that the farmer, therefore, 
can never bestow too much pains on making and preserving all 
the manure which it is possible to produce on his own premises. 
It may well excite surprise to see, in some districts of this 
country, a great quantity of straw left upon the land by a slovenly 
mode of harvesting, where it is of no use, which, if carried home, 
would greatly increase the quantity of dung in the fold-yards, 
while at the same time the farmers are buying bones or other 
manures to supply their deficiency. 
Dilston, February 13, 1843. 
