FARM DRAINAGE

Manawatu Times, Volume LV, Issue 7322, 4 September 1930, Page 10

FARM DRAINAGE

Often a Sound Investment COST OF MOLE DRAININGA prolonged spell of wet weather, with its consequent water-logging, oi pastures, shows up weaknesses in farm drainage and has turned the thoughts of many farmers in the direction of improving existing conditions. The high cost of the materials required for the draining makes this an impossibility for all but the very intensively managed farm, or for the orchard, and tho solution of most of our drainage difficulties lies in the direction of mole draining. This type of drainage has been used successfully in England for more than 100 years, but has come into greater favour recently, largely as the result of improvements in tractors. Prior to the advent of the tractor, mole draining had to be carried out by a traction engine at fairly heavy cost, or else through winches, which were too slow. Tractors, and especially the heavier types, made the hauling of the mole plough easy work and reduced the cost of the operation very much. It has been estimated, in work conducted by the Fields Division of tho Department of Agriculture, that the cost of mole draining works out at about 10/- per acre where the farmer owns his own tractor. This estimate makes allowances for depreciation at tho rate of 2/6 an hour—a generous estimate. Where the work has to be carried out by contract, with the contractor taking all the risks attached to the ownership of plant, the cost would, of course, be about doubled.

Do They Last? Most farmers, even if they have never drained their land, have seen the mole drain ploughs, with their long, deep share and tho little steel mole which makes the hole at whatever depth the plough is set. Those who have never drained often wonder whether these mud holes will stay firm and really carry off the water. On good, stiff soil they often last 20 years or more, and even where the ground is not very suitable they have a useful life of at least three to five years. Their value is greatly enhanced if the variant outlets arc piped, for this prevents the -earth breaking away at the outlets, clogging tl)6 end of the drain and allowing the whole thing to become blocked up. The extra time and cost of doing this work is well repaid in the greater life of the drains and their greater efficiency. Mole drains are usually run off about nine feet apart and the plough set to a depth of IS inches. Ploughing and all farm operations can be carried out above the drains without the slightest damage being done them. If only portions of a paddock are badly waterlogged, it. might be advisable to place the drains a little closer in these parts, as the water will be mare quickly run off and the pastures thus freshened up earlier. ' When to Drain The winter and early months are the best for doing drainage work, for the land is then wet and heavy and the drains can be more efficiently made. Once made they start to carry off the water at once, and thus improve the pasture for the coming season. If left until later in the year, when the land is comparatively dry, it is not possible to see their effect so clearly. Drainage has an effect in a number of different directions. In the first place, land that has had much weedy growth, when well drained, will grow . better grasses. Tho reason for this is that when much water is present in the soil it is cold. The removal of that water allows the sun to warm the soil bettor, thus providing conditions more conducive to tho growth of better .class pasture plants. Then, again, drainage has a very important effect on the utilisation of fertilisers. It is true that on badly drained land better returns are secured if fertilisers arc used than if

they arc not, but it is equally true that still bigger returns would accrue were drainage to be carried out. Before draiuage is carried out a good deal of thought is needed, for with mole drains it is essential that there be as few ‘ ‘ dips ’ ' in the drain as possible. These tend to let the water gather at one point and weaken the walls, eventually causing collapse. The ideal, therefore, is to have the drains running on a gentle and regular slope, but whether this is possible depends very laro-ely on the way the land lies. In most cases a little careful thought givcu before the work starts will allow reasonably good drains to bo made. Other Methods & In many cases low-lying portions of farms arc drained by means of large open drains, and a certain amount of surface drainage carried out by means of small drains leading to them, lho wintry weather will have shown whether or not these need attention, or whether an extension of the existing drains will improvo the pastures, lho hire or purchase of a ditching machine will be warranted in the case of some farms would be better served by this methtod of draining. . In certain low-lying areas, especially on farms which lie behind river stopbanks, it often happens during winter and spring that that the drajps become clogged and large quantities of water lie for considerable periods. Very efficient electrically worked pupms can now be bought to handle this class oi country, and in some districts, where power boards offer a specially ow rate for power used in pumping, the work can be carried out for next to nothing once the pump is installed. Somo ot these pumps will handle up to 30C,000 gallons of water an hour, so tuat they will rapidly clear all the surplus water off the farm, thus preventing waterlogging of pastures and allowing oettei spring production.