HARROWING OR ROLLING?

Otago Witness, Issue 3418, 19 September 1919, Page 10

HARROWING OR ROLLING?

It is not, perhaps, possible to convey on paper the circumstances under which it is advisable to leave land, rolled or harrowed, as such trifling conditions with regard to moisture, the amount of work put into the land, the weather present and prospective, have all to be taken into consideration and can only be decided upon on the farm, or rather, in the paddock being worked. Many root and grain crops have been adversely affected by the final workings being done by the roller instead of the harrow, and vice versa. Generallv harrowing is more beneficial than rolling, though the latter is the more popular operation. The two operations have, if we expect the breaking down of big dry caked lumps of soil with a heavy roller, opposite effects. Harrowing conserves the soil moisture and keeps it in the ground by preventing evaporation; rolling dissipates the moisture and dries the land by bringing the moisture to the top and encouraging evaporation. If these facts were generally appreciated one would not be in doubt whether a paddock should be harrowed or rolled first. In most cap.es the harrow should follow the roller. The only exception to this rule is when small seeds are sown with a cereal,- for by harrowing to cover in the seeds and then rolling, the moisture is brought right up to the surface, and the rapid germination of the seeds is assured. There is, however, an objection to this method in a dry area. The small seeds may be quickly germinated, but if a dry spell is experienced the grain crop is bound to suffer, and the seed bed drv up to quite a depth by the moisture being drawn up from below bv capillary attraction and evaporated. Any observer will have noticed that a well-worked surface soil is infmitelv more moist during a dry period than hard, solidified soil, and even if the well-* worked soil has been dried out in the working it will, if left harrowed, soon become moist, in contrast to the rolled eround, which invariablv dries out info hard clods. Soil moisture is usually wanted in * early summer, and anything which will conserve this .season's rainfall is warranted, and experience has proved that there is no farm implement so effective as the harrow. It gives us the surface tilth, disconnected with the lower, layers of soil, and which, though it dries itself, acts as a mulch in keening the lower soil in moist condition—in fact, it is the nearest approach to the indispensable work of the dutch hoe in our gardens during summer time. The roller has its uses, of course. In the ploughing of a grass or weed-infested paddock which is to be sown, say. with a spring cereal, it is well to roll the more or less thick furrows, in order to re-establish the connection between the furrow slice and the sub-soil, but once made solid, attention to the surface soil is desirable, in order to pi'ovide the fine surface tilth and obviate any danger of the ploughed area drying right out, should a drv period follow. Before one leaves the paddock it is advisable to be satisfied that the last stroke of the harrows has effected that shallow surface tilth, which, although but an inch deep, has been moved and disconnected from the lower soil. Anvthing is better than a soil surface baked and caked by the hot sun after rain. Should the grain sprout and be up. the harrows will do good work if the land has crusted over, and there is little danger of doing much' harm and a prospect of doing a great deal of good. What if a few plants are Dulled up or partially smothered? The benefit derived from breaking a caked surface far more than compensates for any loss incurred in killing a few plants. Generally we would harrow across the drilled rows, although little harm_ would result even by going in the same direction as .the rows. It seems, no doubt, deadly advice, but in a dry season, when the surface has crusted, we have witnessed most beneficial effects, and anything is better than a crop area lying dormant, unable to breathe "owing to a drying soil Jue to a hard surface which is remedial if drastic treatment is attempted. Necessarily, we would not favour harrowing a spring sown oat crop till the plants had a good hold of the ground, say when the plants have at least three leaves, when

they will be ■well rooted and tough and stand a bit of knocking about; or if the seedling has been fairly thick harrowing might be advisable earlier. In the case of wheat good work can be effected when the crop is up some inches high, and even with all cereal crops it will be found that in lands which have been worked for some years- there is a tendencv for soil particles to run together, and harrowing not infrequently will prove a "reviver" on thin or stunted looking crops.