Agricultural and Pastoral.

Hawke's Bay Times, Volume 13, Issue 659, 25 February 1869, Page 4

Agricultural and Pastoral.

SHOULD STUBBLE BE BURNED OBPLOUGHED UNDER?

(Prairie Farmer.)

This is a question which we often hear discussed with considerable earnestness, and, so far as we have observed, the disputants are pretty equally divided. A superficial consideration of the subject would certainly lead one to believe that ploughing stubble under is greatly to be preferred to burning it. It seems natural to suppose that by the first plan we restore to the soil a much greater amount of material out of which to form other crops than we can do by simply burning it. But do we restore to the soil the material in a form that can be assimilated by the next crop ? Can we make this stubble instrumental in increasing the fertility of the land, either by itself or by its action on other substances contained in the soil ? These are questions which it is well carefully to consider. That any considerable quantity of the stubble of ripe grain finds it way into the next crop that is raised on the field, no one will pretend to argue. Thoroughly ripened straw undergoes a very slow decomposition, unless it is exposed to the combined action of heat and moisture ; and experience demonstrates that straw —particularly wheat straw —will often remain in the soil for a whole season with its form preserved entire, and its appearance scarcely changely changed except by the absorption of water. Finally, it is true that the fibre of the straw becomes disintegrated and the carbon is left on the land instead of being consumed. But we must remember that chemically carbon is of no use to the soil, though mechanically it may be, as an absorber of moisture and gases. It is from carbonic acid and not from charcoal, that plants derive their sup ply of carbon. This inert carbon, if we except about one per cent, of nitrogen, is all that is saved to the soil by ploughing the stubble under and that would not be returned to it if the same were burned.

Now let us consider briefly the disadvantageous form in which the mineral salts are returned to the soil in process of turning under. They are in the form of organised matter, and must wait until the organism is entirely destroyed before they can be resuscitated into living forms. The potash, phosphorus, soda, lime, and and silica, separate or in combination, must remain encased in carbon, which is one of the most indestructible substances, until that is slowly wasted away by the action of oxygen. Years might elapse before the silica which is so necessary to give strength to the stalk of the grain, would again be made available. Now, in all our prai rie soils there is a great deficiency of this substance, and consequently the grain grown here is much more liable to lodge than that grown further north or east. It is plain then that we should manage our stubble so that this silica will not become fixed, but will be in a condition to be used over and over again as often as possible. The same thing is true of all the other mineral substances contained in the straw; they are not impoverished by use nor enfeebled by constant employment. Now let us see how farming affects the stubble with a view of making it • available as manure for a future crop The popular idea is that substances are destroyed by the action of flame, but such is not the case. Rot and fire accomplish exactly the same end in changing vegetable substances; but the one effects in a moment what it will require the other years to perform. Each decomposes, neither can destroy ; we have before shown that the sooner this decomposition is effected in the stubble of grain the better will be the results. Straw, from the fact that it contains so little nitrogen and solarge an amount of mineral substance, should be burned; but the same process would be very disadvantageous as regards stable Blable manure, or other substances which are rich in nitrogen. These require to be slowly decomposed, and it is preferable that it be done beneath the surface of the ground in order that all the ammonia which is formed by the disengaged nitrogen and hydrogen may be caved. Charcoal here is necesspry to absorb this gas, and that which is produced from the slowrotting of vegetable matter is very suitable for this purpose. But the same need does not ex*

sist in the lower part of grain straw, a it contains little else than carbon and mineral substances.

Ploughing stubble under may produce some mechanical good on certain soils, that are very clayey or apt to run together and form a coherent mass; but in the great majority of cases stubble leaves the soil quite too porous, and there are few instances where it is not advisable to roll stubble before ploughing, in order to close up if possible, the cavity of the stalks. This loosening of the soils of clayey land is perhaps the only argument, if we except the retention of the carbon, that can be advanced in favor of ploughing under. To offset this we have the additional expense of rolling the land and the great disadvantage of the stubble interfering with the movement of the plough and the turning of the furrow.

But even in the case of clav lands the argument is with the fire. Nothingrenders clay available for agricultural purposes as does heat. It tends to pulverise it and at the same time to render the silica soluble, and in a condition to unite with potash and soda. Every vine-dresser knows, and every grain-grower should know, that there are few better substances to apply to either a vineyard or a field than pulverised brick. The cheapest and by far tbe easiest mode of applying this sort of manure is to burn over a clay field.

But besides the chemical argument in favor of burning stubble, there are others which are equally forcible. Fire as always been known as a purifier, and in no place is it so efficient as in a stubble field. The seeds of the tares which have grown along with the wheat till the time of the harvest are, in a great measure, destroyed by the fire that consumed the stubble, and the same is true to an equally great extent of the eggs and larvae of insects.

WHAT SOILS SHOULD BE DRAINED? Some contend that all lands will pay the outlay on such labor and material. If all lands will do it, then it must be obvious that some lands will pay a very large interest on such investment. What effect can draining have on those lands where the uoderlying is so closely compressed that water will stand in the trench until evaporation takes place ? Such drains might tap the springs, and if the soil has been deepened to a proper depth, the whole land would be freed of standing water, provided the ditches were cut pretty near together. Deepening the soil order must go along with draining, in to derive the greatest advantage from the operation. One great object of this is to distribute the nutritious matter in the surface of such depth as will lead the roots of the growing crop to take a generous hold, and so counteract the influence of wet and drought. The mechanical condition of such soil renders it in a great measure aelf-fer-tilising, the open and porous state of the soil being thus enabled to freely admit the atmospheric nutriment which is carried down in rains and dews. All surface water passes quickly down into the drains, leaving the ground ready to plough or hoe after a storm of any length. Lands that now forbid ploughing till past the season for planting, will be advanced full three weeks, so that potatoes and grain may be put in before the more hurrying business comes on. The equalization of the heat through the whole depth of the soil is secured by the ability of air to circulate through the pores. The crust which bakes and forms on many lands after wet weather, and which is so impervious to vegetation. #'ill never be found on such improved land. All plants throw off poisonous matter from their roots, unless this leaching process removes it beyond their reach. Most soils are supplied with a certain proportion of vegetable matter, which the action of oxygen will gradually decompose for the nourishment of growing plants. No soil that is contained in lumpy earth can ever be available until dissolved or pulverized to powder, and undrained land seldom admits of this process. The spring is earlier and the autumn frost is later on all lands put into this mechanical condition,because the earth is not chilled by evaporation; the sun's rays are absorbed, and the superior warmth dissipates the cold of the night air. Any land on which

water stands after a rain, such as is long wet in spring ; such as it heavy to work at any season j such as does not pulverise readily in working, ought to be drained.