THE EXHAUSTION OF SOIL: ITS CAUSE AND CURE.

Clutha Leader, Volume I, Issue 3, 23 July 1874, Page 3

THE EXHAUSTION OF SOIL: ITS CAUSE AND CURE.

_. .. ... (Continued.)" \ Next follows nitrogen, of "which there exists an enormous quantity in£the* globe, the bulk as before Btated being four parts out of five air. Its presence is almost alto- : gether confined to the'atmosphere, arid/the animal and vegetable kingdom while it forms but a minute part of the mineral world. Nitrogen as a substance i-vinvisible. and without smell or color, but differs. from> oxygen in its action, .as it instantly ex« tinguishes fire," when life is destroyed by : immersion in nitrogen, it is only caused by the want of oxygen, not because nitrogenis poisonous. The same result follows if we descend the shaft of a mine badly ventilated ; we rapidly exhaust'the oxygen of the air, and unless supplied with more from ! the surface, are suffocated, just in the same way 1 the candle goes out for want of oxygen. Nitrogen, in a solid form, is present in all cultivated plant?, such as grasses, roots, -wheat, barley, oats,, rye, beans, peas, &c. ; also, in the flesh of animals, the hair, feather.", and bones. Thus meat supplies us with large quantities of this substance, and such grains as wheat are amply stored with it, as also the bean tribe, which are remarkable for their strengthening qualities. — Carbonic acid gas, - another constituents of the atmosphere, forms about one part in every l-2000th part of air. This substance is the great essential of the growth of plants in supplying them with their woody structure and other constituents held in solution by it, which ia absorbed by plants through their roots. It is an invisible gas, having a slight odour, is considerably heavier than .air, a decided poison to animals, and instantly extinguishes' all burning bodies ; it forms a part of all rocks, minerals, and | soils.; in chalks, marble, and calcareous I rocks it forms nearly half their weight, and in most rocks of this description about 2-2lb. out of every 50lb. consists of carbonic acid gas. Thus it will be seen that this is a most important substance in/the economy of natnre, and is analogous to oxygen iuits effects towards animals. Carbonic acid gas is a compound, thus differing from the two preceeding gases, which are simply elementary ones— -not compounds, but mechanical mixtures, and capable of separation. Carbonic acid consists' of oxygen chemically combined with ' the solid substance of carbon, or charcoal : thus 6lba. of charcoal and 16lbs. of oxyeren gives 22lbs. of this gas. Carbonic acid gas ia always found when oxygen combines with carbon, and as this is the chief constituent of all fuels, it becomes evident tbat large- quantities' escape into tbe air. Carbon also forms a considerable portion of the food of animals,, which by their breathing is converted into carbonic acid gas. Carbon i 3 represented: in coal, soot, wood, stone 3 , bodies of animals, etc. When vegetable Substances are consumed the carbon combines with the oxygen of, the air, and r passes off as/ carbonic acid gas. Its power of absorbing; ammonia gas is very great: in a dry condition it will absorb seven hundred times its own volume of ' this "gas. To' a less" extent, it acts as a disinfectant, and is used^ to remove obnoxious animal or vegetable matters. This will account in some measure; for the fertility of cultivated soils. All highly cultivated soils contain ■ this ..sub- < stance in a different form, which' is called . humus coal, A to distinguish, ,i£ from the other cat Inn or charcoal. The two substances differ thus, that .while, charcoal is " almost undistroyable in the: 'earth, buhrair undergoes a, gradual distraction in the soil, the oxygen. of the air .uniting with it, and furnishing a supply of carbonic' acid fbrttie use of plants. , s The two; materials, however, are alike in one respect, that toe humus coal absorbs iii some/degree; though/ not so greatly, ' the ammonia gas;- of the'atmosphere. -If is from- ; tbjs^sjabitan r c^.thai^ the dark color of the soil is i due.*-— Watery/ vapor is i the fourth ConatiWerlt; p'f^the a?r|f and it.is by, tqis the air w;softene;d>so^that/ the delicate organization^ of -plantsf fand* animals are not injured^as^Bby/iHpuld , be; were the air/ totally, devoid/ of; mois^ To this ;beau|iful; pbenp^^^ w^d^'e^bl muQh/ ; that ■confri 'and! iwelfare^ I'- $f a much value /tp¥the:/agricult^ whichfunusbes, a ben^ .■{jrowtfi^of^^ nature, as befbre/sVsh, by : means of fib mua ; ' *'^ ;S o';/;/^ y^ :t .^S^feS^Sll^vi?

' n ii i i.-ii. — .. ... ..r',;- -■ - ■-■ i- ■' '■■••'- -. . . }■ ,11 i n i .;••„ it is also < 'given; in -email i.-g'siauti-^es-M^^cuhf-.C^''-' ponentformeibyfhitric a;c^into,^itrltte/;'df •" ammonia. / During tHuriderstbrins* caused by the passage .of *-iieQHc^urMntSJ"tKiß^;. salt/is conveyed to earth By the falling rafhf V and to this is.due the freshness of growing/ crops at such a time. c J A few Remarks 'diV*/; ammonia will not be out of ' i,lace"here^.'/< derived, as they are; from the best^modern • chemists on these interesting subjects'. "