86 



Top-Dressing. 



Vol. V. 



land ; it lay on the side of a hill, and was 

 very wet and poachy, particularly during 

 wifiter ; liad been generally cut for hay, al- 

 though it seldom produced more than three- 

 fourths of a ton per acre, and this, not until 

 the end of July ; I drained it, by cutting a 

 ditch at the upper side, deep enough to get 

 below the stratum of clay, turning the water 

 down the sides, and gave it a top-dressing of 

 scavenger's manure, the cleaning of the town 

 streets, and, the year after, it produced me a 

 load and a half per acre, in the middle of 

 June, and a second crop of three-fourths of a 

 load the beginning of September, and this it 

 has continued to do, varying a little, more or 

 less, according only as the seasons were wet 

 or dry. 



And to show the effect of dung buried deep, 

 the following instance may be sufficiently 

 strong. I had noticed, in a field at Wick- 

 ham, in Kent, which was laid down for a 

 cherry-orchard, and planted with fine young 

 healthy standard trees, that for two years 

 made a beautiful and luxuriant growtii, and 

 the third year, in the spring, they threw out 

 their shoots with equal luxuriance ; but, be- 

 fore summer, I observed, to my astonishment, 

 they were all withered and dead. Not being 

 able to assign a cause for such an unusual 

 failure, I called on the proprietor to enquire 

 how it happened; he seemed perfectly re- 

 signed to what he called his ill luck, in hav- 

 ing them struck with a blight; but, perceiv- 

 ing no reason why his trees should be blighted, 

 whilst his neighbours all around should escape 

 uninjured, I enquired farther as to the nature 

 of the sub-soil, when he told me he had been 

 at great expense and trouble to prepare the 

 soil, by giving it a thick covering of rich 

 stable dung, and trenching it in, a spit and a 

 half deep, with the spade; I observed the 

 trees had thrown out a profuse discharge of 

 gum, and have no doubt, that, during the 

 first two years, the roots had not penetrated 

 the dung, but on reaching it, the third year, 

 they were poisoned,* by being so glutted 

 with impure food as to be thus diseased and 

 destroyed. 



And, whatever devastation may be com- 

 mitted by the insect or fungus tribe to trees 

 or plants, I am convinced, that by far the 

 greatest extent of injury, from what is placed 

 to the account of canker, mildews, &c., if 

 correctly investigated, will prove to originate 

 in the unwholesome supply, or impurity of 

 the food. And as to the objection, that by 

 leaving dung on the surface, a too rapid de- 

 composition of the manure will be followed 

 by a too rapid consumption of food, it may be 

 said, " a man cannot eat his cake and have it 



* See page 364, vol. 4, of the Cabinet— Dialogue, Cul- 

 tivatiou. 



too;" let the crop be suited to the manure, or 

 the manure to the crop, and as long as he 

 gets its full value, he will have little reason 

 to complain of its coming into his pocket too 

 quickly ; the sooner he gets a profitable re- 

 turn for one dressing of dung, the sooner he 

 can aflcird another ; and, if a proper course 

 of crops be taken, he may go on a long time 

 without feeling cause to complain that his 

 lands are too prolific, or too rich. 



To be consistent, we must abide by chem- 

 ical principles, or give them up : the difier- 

 ence in the effect of the method I recommend, 

 of applying manure on the surface and there 

 to suffer it to remain the longest period con- 

 venient, and that, by Sir H. Davy, of bury- 

 ing it immediately, may be determined by 

 the comparative formation and effect of the 

 two gases — carbonic acid and carburetted hy- 

 drogen — if the former be, as stated, a princi- 

 pal ingredient in the food of plants, and that, 

 by its gravity, it will descend and penetrate 

 into the soil, no method more favourable for 

 its generation and equal distribution can be 

 found or devised, than by my mode of appli- 

 cation : and, if carburetted hydrogen be ei- 

 ther an unwholesome food, or, by its rapid 

 escape,! tlie occasion of a great waste of car- 

 bon, and nitrogen gas be poison or obnoxious 

 when in contact with the food, no mode can 

 be more favourable to, or productive of both 

 those effects, than burying the dung in an 

 unfermented state. 



If we were to suppose that a difference in 

 the quality of the food supplied to plants pro- 

 duced no difference in its effects, or that the 

 roots possessed the power of selecting the 

 exact quantity and proportion of each prin- 

 ciple required for its particular purpose, from 

 any composition that may be presented to it, 

 we should be driven far off from accounting 

 for the diseases of plants, or for the difference 

 in size, substance, state, and condition of 

 plants of the same species when growing in 

 the same situations; and although we are 

 justified in believing that a plant, having 

 taken in its food in a compound state, pos- 

 sesses the power of dividing and appropriating 



fThen, would it not appear that the gas which is 



constantly flying otf from our dung-hills during their 

 state of fernientalion, and which is always evolved in 

 proportion to the air, the heat, and the light to which 

 they are exposed, is carburetted hydrogen, a substance 

 unfit for the food of plants, and is, therefore, driven 

 away into the atmosphere, to form other combinations, 

 by which it might be prepared for other purposes ? 

 NoWj how strange! to think how carefully we have 

 been covering up our dung-hills with earth, &c., to pre- 

 vent the escape of those gases, which for ages have 

 been considered the richest part of the manure ! but it 

 would seem that nature, after all, knows best how to 

 carry on her operations ; and how will some of our 

 friends, who have thought that they had, long ago, 

 learned all that could be taught on agriculture and hus- 

 bandry, receive this new theory ! Will it not astonish 

 them ? We are, indeed, even yet, only on the threshold 

 of the science of agriculture ! 



