ON MANURES. 13 



found in the land in clods sometimes so long as two or Uiree 

 years ai"ter it has been laid on. Its effect upon the soil is 

 slower tiian that of horse-dung : it has been also considered 

 more durable ; but, as we have already observed, this latter 

 effect must in a great measure depend upon the nature of the 

 food by w^hich it has been produced. Whatever may be 

 the degree of fermentation at which it has arrived, it does 

 not seem to occasion any perceptible heat when laid upon 

 the land ; for which reason it is best adapted to dry and warm 

 soils. Thus, upon sands and gravels, which, from their nature 

 are apt to be hot, its cooling qualities counteract that effect, 

 and upon such land it has been found of infinite service ; but 

 upon strong clays, it appears to be nearly inoperative if buried 

 under the ground, and not exposed to contact with the atmo- 

 sphere by repeated ploughings. When used alone, it has, 

 however, been considered, in most instances, as nearly worth* 

 less ;* and the most advantageous mode of employing it is to 

 form it into a compost with the other contents of the farm-yard. 

 It has also been tliought that the dung of milch cows is inferior 

 to that of oxen ; but this can only be attributed to their yield 

 of milk, which probably deprives it of some portion of its rich- 

 ness, and when they are dried off and fattened, there is no 

 perceptible difference. 



Sheep-dung decomposes quickly when it is moist and com- 

 pactly heaped together ; but when dry and dispersed, its de- 

 composition is slow and imperfect. Its effect upon the soil is 

 soon dissipated, and is generally exhausted after a second crop. 

 Much ammonia is disengaged from the excrements, and more 

 especially from the urine of sheep, and this renders their ma- 

 nure particularly valuable upon soils whicli contain insoluble 

 mould. That which is found on the floor of sheep-cotes, when 

 left undisturbed, is of two qualities — that of the upper layer, 

 which is occasionally renewed with fresh litter, being strawy, 

 dry, and not fermented; w^hile, on the contrary, that of the 

 under layer is moist, clammy, and fit for use. When the 

 dung is removed, care should therefore be taken to mix both 

 layers, so that they may be equally decomposed ; and, when 



*An instance is mentioned in the Essex Report of 15 acres having been 

 manured for beans— 6 with horse-dung, and 9 with dung from the cow-yard ; 

 and that the acres produced far more than the 9. — Vol. ii. p. 230. In an 

 experiment, made near Grantham, in Lincolnshire, on a poor dry soil, the 

 manure from a horse-yard, and that from a yard where neat cattle were 

 wintered, were used separately for turnips, and the former was found to 

 have greatly the advantage. 



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