On Manures. 203 



land lies conveniently beneath the farm-yard, the contents 

 of this reservoir, or the overflowings of the dung-yard, may 

 be conveyed to it, for the purposes of irrigation ( l73 ). 



2. Preparing the Materials for Use. 



On this head there is a great diversity of opinion ; some 

 contending, that dung cannot be used too soon after it is 

 made ; and others, that it cannot be too much rotted. The 

 various circumstances of climate, soil, and crops to be raised, 

 render different practices equally proper. 



Much depends upon the climate. The farmers of Picardy, 

 and other parts of France, for instance, may find the conti- 

 nual carrying their dung to the field practicable, but this can- 

 not be accomplished in less favourable climates. What is 

 found beneficial in warm climates, may not answer in a cold 

 one. Besides, in wet soils and cold climates, when the dung 

 is bestowed only in small quantities, so little of it is kept toge- 

 ther, that fermentation in the ground is retarded, until it is 

 too late to be of any material use to the crop sown with it. 



The advantage of using fresh dung, must also depend up- 

 on the soil. Practical farmers are in general of opinion, 

 that long dung is more applicable to strong, than to light 

 land ; and as it has a tendency, by its fermentation, to divide 

 and to loosen the constituent parts of the soil, and furnishes 

 matter which prevents the particles of clay from coming in- 

 to contact, and adhering together, it must necessarily have 

 a much more desirable effect on soils that are too compact, 

 than on such as are already too light and open ( l74 ). Hence 

 it is recommended, on a true carrot soil, to use dung, after 

 all its parts are dissolved, and incorporated into one com- 

 plete mass, by means of putrefaction ( l75 ). 



In regard to the crops, it is remarked by Sir Humphry 

 Davy, that straw fermented, is a more manageable substance, 

 and furnishes more manure for a single crop, than un ferment- 

 ed. In the latter state, it decomposes more slowly, and con- 

 sequently, though its influence will be more lasting, yet it 

 produces at first, less effect. But in the case of turnips, un- 

 der a proper rotation, the first crop is all that it is necessary 

 to manure ; the dung given to that crop, more especially 

 when the crop is consumed upon the land, being the means 

 ot fertilizing the whole course of succeeding crops, whether 

 barley, clover, wheat or oats. Besides, when dung is fer- 

 mented, the seeds of weeds, and the eggs or larvae of insects, 

 are destroyed. 



