42 A PRACTICAL TREATISE 



land in their liquid form ; or, should the construction of such 

 reservoirs prove inconvenient, the waste of the liquor rnay be 

 prevented by raising the dung-hill in the manner already 

 stated in our account of the preparation of farm-yard manure. 

 The application of such moisture cannot be considered as a 

 loss; and we have already seen that even that of watering 

 dung-hills is sometimes necessary to prevent them from be- 

 coming fire-fanged. 



The escape of gaseous matter is caused by the heat created 

 by fermentation ; and if we look to the state of a ikrm-yard, we 

 sliall find that the moment the dung is thrown out, trampled 

 upon, and wetted by the cattle, that process is* commenced, 

 although the temperature of the heap should be far below 

 100°. But although the bulk of the manure is thus diminished 

 by the evaporation, yet the effect upon vegetation of the am- 

 monia contained in the vapour has not been conclusively 

 ascertained ; nor is there any proof that animal and vegetable 

 substances, while in a state of fermentation, contribute to its 

 support ; for it appears from numerous experiments, that rank 

 manure, although forcing the early growth of living plants, 

 yet eventually contributes to their premature decay. Practice 

 has long since decided that it is injurious to turnips, to which 

 crop it is more profusely applied than to any other :* it renders 

 corn crops foul; and on light and poor land, which, containing 

 but little nutriment in the soil, requires all that can be fur- 

 nished to it by the manure for the support of the present 

 plants, its effect, though often seen to occasion them to push 

 forth with great apparent vigour, yet frequently leaves them 

 deficient in grain and subject to rust. The potato is, indeed, 

 almost the only plant to which it has been found decidedly 

 friendly; but even that is in many soils known to succeed 

 better with short dung. 



Respecting the effect of unfermented dung on Mr. Cokeys 



* Mr. Walker, of Mellendean, who rents about 2800 acres of arable land, 

 has found by the experience of thirty years, that a small quantify of rotten 

 dung is sufficient for a crop of turnips, and that all the succeeding crops, in 

 the common rotation, are also generally good; but he could never raise a 

 full crop with long fresh dung, which, from its openness, tends to admit 

 drought, instead of affording moisture and nutriment to the roots, while 

 they are young and tender. lie is therefore at considerable expense in car- 

 rying out, turning and re-turning his dung-hills, so as to have the dung in a 

 putrid state when laid upon the land in the month of June. After all, he is 

 every year obliged so to manure a part of his turnip land with fresh dung, 

 and whenever that is laid on, the crop i* invariably much inferior, — Husbandry 

 of Scotland, vol. i. p. 161. 



