186 



Manures. 



Vol. XI. 



Manures. 



By repeated cropping, the best soils be- 

 come exhausted of their fertile properties, 

 while naturally indifferent soils require the 

 administration of certain qualities, before 

 they will yield a due return to the labours 

 of the husbandman. There are, no doubt, 

 soils so naturally rich in some parts of the 

 world, that, though used for twenty or more 

 years in growing successive grain crops, 

 they show no indications of impoverishment; 

 yet even these must in time be exhausted, 

 and therefore, in all circumstances, manures, 

 or artificial fertilizers, require the conside- 

 ration of the husbandman. In our own 

 country they are of the first importance. 



Manures are of two classes, both of which 

 have distinctive characters, and perform dif- 

 ferent offices in the economy of vegetation. 

 The first of these comprehends all animal 

 and vegetable decomposing matter, and is 

 principally employed in feeding the plant, 

 augmenting its size, and sustaining the vital 

 energy. The second operates more on the 

 soil and decomposing matter than in directly 

 contributing to the support of the vegetable. 

 The first kind has been called animal and 

 vegetable, and the second fossil, manures. 

 Under this second class are ranked not only 

 lime, marl, and gypsum, but sand, gravel, 

 and clay, so that all the meliorations which 

 are effected on soil by blending and com- 

 pounding the original earths, are compressed 

 within its limits. 



The animal and vegetable manures, which 

 are putrescent in their nature, are foremost 

 in importance and dignity. They consist of 

 certain elementary parts of animal and ve- 

 getable substances, elaborated by a natural 

 chemical process in the course of the de- 

 composition or decay of the bodies. The 

 excrementitious matter, or dung of all ani- 

 mals, is no other than the remains of the 

 vegetable or animal food which has been re- 

 ceived into the stomach, undergone there a 

 partial dissolution, and been thrown out as 

 unserviceable for the further nutrition of the 

 system. From this universal decay of or- 

 ganized matter, and its conversion into fluids 

 and gases, it would seem that animal and 

 vegetable substances, and excrementitious 

 matter, are resolvable into each other, and 

 are only different parts of the same original 

 principles. The essential elements of them 

 all are hydrogen, carbon, and oxygen, either 

 alone, or in some cases united with nitrogen. 

 Conveyed by liquids or moist substances into 

 the ground, these elements are sought for as 

 nourishment by the roots of plants, and so 

 form the constituent principles of a new ve- 

 getation. Inasmuch as flesh consists of a 



greater concentration of these original ele- 

 ments than vegetables, the manure produced 

 by carnivorous animals — man included — is 

 always more strong in proportion to its bulk 

 than that discharged by animals who live 

 only on herbage. Experience fully proves 

 that all animal and vegetable manures are 

 but varieties of one kind of principles; their 

 actual shape and appearance being of much 

 less consequence than the degrees of strength 

 in which these principles reside in them. 



Whatever be the value of the elementary 

 principles of manures, practically they are 

 of no use as manure till they are disengaged 

 by putrefaction. It may be further observed, 

 that putrefaction is in every instance pro- 

 duced by the elementary principles being 

 set at liberty either in a fluid or volatile 

 state. If a quantity of stable dung be piled 

 into a heap, and freely exposed to all varie- 

 ties of weather, it soon heats and emits a 

 stream of vapour, which is often visible as a 

 cloud over it. These vapours, and also the 

 odours sent forth, are gases escaping, and 

 the heap is constantly diminishing in weight 

 and volume; at the end of six months, if 

 there have been alternate moisture and 

 warmth, not above a fourth of the original 

 essential material remains to be spread on 

 the field; there maybe in appearance nearly 

 as much substance, but it is comparatively 

 of little value — the real manure is gone, and 

 what remains is little better than a mass of 

 unputrefied rubbish. 



It may be safely averred, that no principle 

 connected with agriculture is so little un- 

 derstood or thought of as that which has 

 been now mentioned. We therefore crave 

 the most earnest attention to it by every 

 reader of these pages. Generally speaking, 

 the excrementitious matters thrown to the 

 dung-hill are treated with perfect indiffer- 

 ence as to the effects of exposure and drain- 

 age away in the form of liquids. It cannot 

 be too strongly stated that this is a gross 

 abuse in farming. The putrescent stream 

 contains the very essence of the manure, 

 and should either be scrupulously confined 

 within the limits of the dunghill, or con- 

 veyed to fresh vegetable or earthy matter, 

 that it may impart its nutritive qualities. 



A knowledge of this important truth has 

 led to the practice of making compost dung- 

 heaps, in which the valuable liquids and 

 gases of different kinds of manure are ab- 

 sorbed by earth, or some other substance, 

 and the whole brought into the condition of 

 an active manure for the fields. Hitherto it 

 has been customary to speak of dunghills, 

 but there ought to be no such objects. The 

 collection of manure from a farm-yard and 

 offices should form a Axing-jnt, not a dung- 



