THE GARDEN.

New Zealand Tablet, Volume IX, Issue 454, 23 December 1881, Page 23

THE GARDEN.

On the Efficacy of Trenching. — Before manuring and trenching vacant ground it is necessary to decide oa the rotation of crops to be cultivated on it during the ensuing summer. This arrangement should be made, not for one year only, but for three or four years. One of the first principles to be attended to is that no aunual crop be grown for two successive years in the same plot of ground. Another thing should be attended to, and that is, that crops should not he allowed to follow each other which are liable to he preyed upon by the same kind of insects, as the increase of these pests are encouraged, to a great extent, by putting into their way the very food which they are most fond of. It is important that both the manuring and the depth of the trenching be regulated by the requirements of the crops, and the rotation should be so arranged that the ground be not trenched to the same depth for two successive seasons, but so that different poitions of the soil be brought to the surface in turns. The perennial or permanent crops, such as asparagus, seakalo, rhubarb, &c, will, of course, form a class t>y themselves, as they do not require a change of situation for many years ; but when a change is necessary with any portion of them, the ground from which they Vare removed will fall into the ordinary rotation in the way of a regular exchange. The working and turning over which the celery soil undergoes acts admirably in preparing the ground for deeprooted plants, such as parsnips, carrots, turnips, and onions, and in the following year the same ground may be devoted to the cultivation of cabbages, cauliflowers, broccoli, &c, whose roots are confined much

nearer to the surface. Should the vegetable gaiden be large enough to allow the cultivation of a portion of the potato crop, it will form a fourth course in the rotation, and will come in after the cabbage tribe. Acting on this system, cabbages have been planted during the autumn on ground which has been occupied by early summer turnips ; and the ground which now requires trenching is that from which the late turnips, carrots, beetroot, Sec, have been removed, and which will next spring be planted with cauliflowers, cabbage, &c. Preparations for these should be made by trenching in a heavy dressing of manure, which will serve for that and the succeeding crop. The trenching of the ground should be carefully done. "We will briefly describe our pystem of pei forming the work. On the plot of ground to be trenched we cart a sufficient quantity of manure, which should be left in heaps to be used as required. Then commence at the lowest end of the ground by opening a trench two and a half feet wide and the same in depth. This earth should be carted to the opposite side, where the work is to finish. Mark off with the garden line two and a half feet of the top spit, which, together with all loose soil, should be turned into the bottom of the tiench. Over this place a good covering of manure, then another good spit of earth, which will deepen the trench to the required depth of two and a half feet. The soil carted out of the first opening will fill up the last trench. Avoid trenching in severe frost, as the digging in of frozen earth will chill the ground and keep it cold for a long time, and retard the sowing of vegetable seeds. It has been often maintained that if the subsoil of a garden is hungry poor stuff it ought not to be brought to the top by trenching, but few greater mistakes are made than that of leaving a bad subsoil undisturbed. It is, perhaps, the worst possible advice to give in some cases, if by trenching the gardener will only understand the ordinary process of putting the top spit of good soil at the bottom, and bringing up the bottom spit of bad soil to the top ; but the quality of the top and bottom soil ought to decide how the trenching is to be performed. For example, let us take tlie worst possible state of ground for trenching operations— bad, poor, sour subsoil, which in its present state will grow nothing well. A little of it might be brought to the top every time the earth is dug, because, exposing even bad soil to the atmosphere will improve it, and, if good earth reached only ten or twelvei nches down, this top soil, when we begin to dig, must be removed one trench wide for the first operation, for the purpose, as already stated, of filling in the last trench left. The soil of the first trench being removed for a start in ordinary digging, the nest spit dug all along will fill it up, and the ground would be merely turned over ; but before we go at the second spit it would be wise to loosen the subsoils with a steel digging-fork, for next to bringing it to the top loosening it at the bottom is best ; but taking out about two inches to put on top of the good soil will be found an excellent mode of improving the ground permanently. Then dig the second spit along the space to be trenched and throw it into the trench, loosen the bottom again, and throw two inches of the earth on the top of the good soil. Continue this all through, one trench after another, until it is all finished, and the result will be that a small quantity of worthless stuff will become by exposure to the atmosphere a valuable and useful soil.— Dublin Freeman.