No. 3. 



Top-Dressing. 



85 



effect will be found to be almost instantane- 

 ous. Quere — would not this be the proper 

 way, namely, by top-dressing- — of expendinof 

 that very strong and effective article lately 

 brought into use, by an incorporated company 

 too — Poudrette 1 I think it would, and ven- 

 ture to propose a trial. 



To many, the system of top-dressing will 

 be novel, and contrary to all their precon- 

 ceived opinions, and yet the practice boasts 

 of the weight of many great names in its 

 support, amongst the rest, of Joseph Hay- 

 ward, who, in his " Science of Agriculture" 

 — a rare and most valuable work — thus ex- 

 presses himself on the subject. 



"I shall hereafter state my reasons why it 

 is improper, as a general practice, to manure 

 lands that are intended for immediate seed- 

 crops; but there may be cases where the 

 state of the soil, from poverty and other cir- 

 cumstances, requires it; and, in these cases, 

 I am convinced that the best time and man- 

 ner of supplying dung for such crops is, by 

 spreading it over the surface, after the seeds 

 are sown. At tirst sight, and according to 

 Sir H. Davy's notions, this may appear to be 

 a wasteful practice, but it is far otherwise ; 

 for, as he says, 'organic substances, as soon 

 as they are deprived of vitality, begin to pass 

 through a series of changes, which ends in 

 their complete destruction, in the entire sepa- 

 ration and dissipation of the parts : animal 

 matters being the soonest destroyed by the 

 operation of air, heat, and light ; vegetable 

 substances yield more slowly, but finally obey 

 the same laws; the periods of the application 

 of manures, from decomposing animal and 

 vegetable substances, depend upon the know- 

 ledge of these principles.' Now, notwith- 

 standing the manner of applying the dung 

 which I recommend — that of spreading it 

 over the surface, and there permitting it to 

 remain, before it be ploughed in, twelve 

 months or more — is directly opposite to that 

 recommended by Sir H. Davy, it will be found 

 more completely accordant with the princi- 

 ples of Mr. Kirwan ; for, by leaving dung 

 openly spread on the surface, it is evident 

 that the influence of the air, the heat of the 

 sun, and light, will be the least controlled or 

 obstructed, and consequently, the decomposi- 

 tion will be more rapid, regular, and con- 

 formable to the wants of the^plants. Under 

 such circumstances more carbonic acid may 

 be generated, but as this elastic fluid is hea- 

 vier than the atmospheric air, it will fall on 

 and penetrate the open surface of the soil, 

 and thus accord in effect with the experi- 

 ments, cited by Mr. Kirwan, of Dr. Priestley 

 and M. Ruckett. And as to any loss arising 

 by the evolution of any other gases, they are 

 less likely to occur from dung in this situa- 

 tion than when buried, for carburetted hydro- 



gen gas is formed in the greatest quantity 

 during the putrefactive process of fermenta- 

 tion, and when the substances are immersed 

 in or glutted with water, and excluded from 

 the air and light ; and in this state they most 

 generally are when buried ; and this gas, 

 possessing an opposite quality to the carbonic 

 acid gas, in being much lighter than the at- 

 mospheric air, will, as it is formed, operate 

 in a reverse manner to the carbonic acid, for 

 it will, immediately on being liberated, pene- 

 trate the surface of the soil, moimt rapidly 

 into the atmosphere, and pass off with the 

 wind, and be thus lost. And, further, it is 

 well known that animal and vegetable sub- 

 stances, decomposed by the cold putrefactive 

 fermentation under the earth, or at the botr 

 tom of stagnant ponds, are inert and ineffi- 

 cient, at least until they are made to undergo 

 some other chemical change, by calcination, 

 oxidation, &c., and this is evinced by peats, 

 bogs, &c., and we may likewise instance the 

 effect of the accumulated animal substances, 

 decomposed under the earth in burial-grounds, 

 v.'hich never exhibit any comparatively ex- 

 traordinary luxuriance of vegetation. And, 

 as a practical demonstration that dung, when 

 laid on or near the surface, and repeatedly 

 turned over and exposed to the action of the 

 atmosphere, is not very rapidly or very effec- 

 tually exhausted, I shall state a course of 

 operations which were carried on, in a field 

 of about six acres, within my immediate ob- 

 servation. 



The soil of this field was a fine friable 

 loam, and of a black colour, but the surround- 

 ing land, although of the same texture, was 

 of a foxy brown ; this difference in the colour, 

 no doubt, was occasioned by the difference in 

 cultivation and manuring: the surrounding 

 lands had been treated in a careless, slovenly 

 manner, as a common farm, whilst the field 

 in question was cultivated as a market garden, 

 and manured at least once in the year, for 

 many years. At the period it came under 

 my notice, the market gardener had died, and 

 it fell into the hands of another person, who, 

 having but seven years of a lease to run, de- 

 termined, as he said, to work it out; he 

 therefore sowed it with white wheat for five 

 years following, without giving any manure. 

 The first year it produced 48 bushels per 

 acre, and every year after the crop declined 

 but three or four bushels per acre ; the sixth 

 year it was planted with potatoes, without 

 manure, and the crop averaged fourteen tons 

 per acre ; the seventh year it was sown with 

 wheat, without manure, and it produced up- 

 wards of thirty-two bushels per acre. 



And, to show the beneficial effects of top- 

 dressing, I shall also state, that about that 

 time I took possession of a pasture-field of 

 about twenty acres, a strong yellow, or foxy 



