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ters is, that dung is the most valuable of all manures ;—that theproductions of every farm chiefly depend on the quantity whichcan be collected, the care with which it is managed, and thejudgment with which it is applied ;-^-that lime or other substancesmay fail of efficacy on repetitions, or evince none on some soils;but dung increases fertility on all soils, and on all occasions.Whatever difference of opinion exists about the preparation, itis generally admitted that it should be regularly spread, andits parts fully disunited and separated; *—that moderate dung-ings, frequently repeated, are greatly preferable to large dos-es, applied at more distant periods. Thus it appears, that or-ganized bodies, putrefied, are the only direct food which hu-man industry can administer to growing vegetables ; and there-fore the careful collection, and judicious husbanding of them, isan important branch of the art of Agriculture.
Town dung differs from that made on farms, only in contain-ing a large proportion of the spoils of animals and of ashes orearthy substances. Its operation has been found quicker andmore powerful, but not so lasting. Farmers who have used bothon conterminous lands, observe, that there is always a more lux-uriant vegetation, the first year, where the former was laid, but lit-tle or no difference in the succeeding crops. For this reason, it isnot uncommon to lay the farm dung on land for wheat which issown in autumn, and town dung for spring crops. Hence it isevident, a difference exists between animal and vegetable substan-ces in their operation as manures; the former, being most soluble,seems to furnish the most immediate subsistence to growing plants.
But the prevailing practice in making manure, is to mix bothanimal and vegetable substances together. It is judged improperto keep them separate, and besides would be attended with incon-venience. We have therefore no decided opinion of their com-parative character and value. Hence nothing can be said ofspoiled flesh, fish, and oil, animal substances ; or of malt dust,rape and lintseed cake, vegetable ones, not included in the aboveenumeration. Like other putrescible bodies, they may no doubthe used to promote vegetation, when they can be had on suchterms as to be profitably applied to that purpose. But seldom
* It has of late become a prevailing opinion, that dung should be deep-bu-ried in the soil at first, and that it will be raised higher by after ploughings;—that, by deep covering, the dung is defended from the injurious effect of exha-lation, and the roots of plants soon find their way to it. 13ut there are peopleof accurate observation, who, from long experience, have found, that if clungis only covered, the nearer the surface it lies, its effects in promoting fertilityare the greater. And they assert that this ought to be so : for then it lies nearfhc roots of young plants, at the time when they need the most cherishing nou-rishment. Those people also declare, that they never saw dung, after it hudlain mixed with the soil for a season, rise to the surface. On the contrary,they observe, that as it dissolves in the earth, the solution descends as low a#'the soil has been stirred by the plough.