SUBSOIL DRAINAGE AND IRRIGATION.

New Zealand Herald, Volume XXVIII, Issue 8540, 14 April 1891, Page 6

SUBSOIL DRAINAGE AND IRRIGATION.

At the recenb meeting of the Northcote and Birkenhead Fruit-growers' Association Mr. W. Daweon, Hellyer's Creek, submitted the following paper upon this important subject :— In these times of heavy taxation, keen competition, and glutted markets, the man who tills the ground has a difficult task before him in finding some way to get any return for his labour, and all his thoughts and energies must be concentrated to getting the largest, earliest, and best crops at the least cost, and with the smallest amount of labour. Some of the most important conditions required to obtain these results are warm, fertile soil and plenty of water at the right time, which means and introduces my subject, " Subsoil Drainage and Irrigation." NECESSITY OF DRAINING. As farming is year by year becoming more a matter of science, drainage becomes a thing of the greatesb importance, and comparatively a necessity. It may be broadly stated that all land, with the exception of very light sorbs, with porous subsoils, are benefited by draining ; and heavy clay soils derive a special benefit, difficult to estimate at its full value. MODES OF DRAINING. Draining of land is divided into two parte : surface or temporary draining and subsoil or permanent draining. I will only deal with subsoil draining now, leaving the surface draining till we come to deal with the subject of irrigation. Important as -it seems, subsoil draining has received little study till the last three decades. Many contrivances have been and are still used to provide these drains, or subsoil watercourses, such as filling in the bottom of the trenches with stones or lon<* rods, covered with sod to keep the earth from choking the water space; but most of these more or less unsatisfactory methods have given way to tile drains, of which several sorbs are in use, such as the Vshaped tile, either covered with a flat pan bile, or else the U tile, laid on the flab pan tile bed; the oval-shaped tile with a flat sole, and the circular drain pipe, now mostly used, are decidedly the best. The former shape of tile requires the drain bottom to be very carefully formed, or they will not keep in position, whereas the circular pipe, having no feeb, is much easier bo lay true, especially if a proper-sized scoop is used for rounding the bottom of the trench. A very quick method of draining, required to last only for two or three vears, is done by a contrivance called the mole plough. This plough is made by attaching to the ordinary plough beam a vertical steel plate about three feeb deep. A poinbed plug of iron is fastened bo the bottom of the plate by a few links of chain, and the machine is seb to the depth by adjusting wheels. The plate cubs into the ground, dragging the plug afber ic, and making an earth drain which answers the purpose very well for a year or two. This plough, requiring twelve horses to draw it, renders the method impracticable for the ordinary farmer, though it is very useful where large areas require to be temporarily drained.

A DRAINAGE PLAN. A good deal of judgmenb is required in setting out drains, or the labour and expense will be useless. A common error is to arrango the lines of drains up and down the slope. As the water percolates down the hill through the soil, drains so laid will only take the water that sinks through the soil directly over them. The gravitation of the water down hill, together with capillary action, overcomes all tendency to lateral drainage. The proper method, therefore, of draining is to lay the main drains (which should be of four-inch pipes, unless the field has a good slope) down the hill, and the collecting drains branching from each side of the main drains and so contrived wibh tho slope as to give a fall of from one in 300 to one in 500. Drains so laid will intercept and carry off every drop of surplus water passing through the soil. These branch drains should be carefully butted together, and the joints covered with a piece of sod with bhe burf downwards to keep out the earth till the filling in has well settled. A good plan, which I have adopted, is to cover the entire length of pipe with tea-tree brush about two inches in thickness.

REASONS FOR DRAINAGE. The depth at which drains should be laid depends much on the stiffness of the soil and the character of the crops to be grown. For cereal or meadow from two ' feeb six inches to three feeb in depbh is deep enough ; bub for orchards the drains must be three feet six inches to four feet deep, or there is great liability to have them stopped by roob-growbh. Deep drains may be laid up to one chain apart, but the shallow drains should nob exceed half that width aparb. Local circumstances will require variations of detail bub the general system will bo the same. Drains have other uses besides carrying off water which are of great importance to the agriculturist. Thus they cause additional warmth to the ground by the process of continually creating a vacuum, as when the rain enters the soil and is carried downwards, and away by gravitation through the drains, warm atmosphere follows to fill up the crevices left by the draining away of the water; thus the soil accumulates warmth to a greater depth than it could do if the earth remained full of water, which absorbs heat much more quickly than soil, and gives it off again in evaporation, instead of storing it as in the case wibh well-drained soils, natural or otherwise. Anobher use, and a very important one, is attracting moisture to the ground. During night time, when the temperature of the atmos- [ phere is cooled down, a currenb of cooled j air enters the mouth of tho drains by reason of the superior heat of the soil. The currenb of air carries with ib a largo amount of moisburo which is retained by the soil, whilst bho air, being warmed by contact with the stored or latent, heat in the

ground, rises through to the surface, oxidising the earth during its passage through. In addition, the drains freeing the soil more speedily of water, during rains a much greater quantity of water passes through the land, enabling the soil to abstract more nitric acid and ammonia than it otherwise could if the water simply ran away over the surface. Many other reasons could be urged in favour of drainage, but I have said enough to show the importance of the subject, and so will pass on to IRRIGATION, which has been practised from remote antiquity. The natural overflowing of many large rivers depositing their riches on the lands adjoining their course, would quickly point out a method of enriching the soil, and lead the inhabitants to construct nrti- ! ficial canals to irrigate larger areas than would be naturally covered by the floods. The nations who appear to have practised irrigation from the remotest ages are the Egyptians and Chinese. The rivers flowing through these countries alrorcl the greatest scope for irrigation, as they take their rise in ranges of mountains covered with eternal snow. Ice and snow being the most powerful agents for breaking down and dissolving rocks, it follows that the melted snow will carry off more sediment than rivers which are fed simply by rainfall; also such rivers have the peculiarity of rising towards the end of the summer, that being the time when the snow-line rises by reason of the increased temperature to its highest level, freeing vast quantities of earthy matter during its melting, which quickly finds its way into the rivers, and is carried down to the plains. Glaciers also contribute enormous quantities of detritus by mechanically eroding the surface of the rocks over which they pass. In the of the Yellow River in China, the volume of water brings down such vast quantities of mud that the river bed in the plains is many feet above the ordinary level of the ground for over one thousand miles, and every few years an extra flood breaks the banks, causing inundation of thousands of square miles of country, and frequently the course of the river is diverted into new channels many miles from the old course. These periodical floods, though incalculably disastrous at the time, cover the land with so much mud that it has become the mosb fertile region in the world. In the ordinary course, when the rise can be kept within bounds, the water is diverted into channels over the entire surface of the country, the fields being made into shallow square tanks, in which the mud settles and the rice is planted. The Nile is another example, but does not overflow with such disastrous results. For diverting the water during such periods as when the river level

is too low to naturally overflow tbe land, the shadoop or water-wheel is used in Egypt and in China. The water is mostly lifted by hand in buckets. In modern times, like subsoil drainage, irrigation has received the greatest attention, and has been reduced to a science. In India vast irrigation works have been constructed by the Government, entire rivers being diverted and distributed over the land. The same baa been done in America and Australia. METHODS OF IRRIGATION. I will try to describe the principal methods of irrigation, the object of each being to deliver an even volume of water over the/surface of the ground. When the land has any fall, the usual practice is to divert the stream at the highest possible poinb, and contour a channel round the crest of the valley as far as possible ; the lower side of the channel bank being finished off quite level, the water filling the channel flows over the bank in an even stream, and runs over the surface of the ground till it all soaks below the surface. This water is again collected by means of 1 subsoil drains, which discharge into another contoured channel at a lower level, and the operation is again and again repeated to the bottom of the valley, thus keeping a copious moisture over a surface of ground that otherwise would become quite dry during summer. Where the surface of the ground is too flat to permit of overflowing, the practice is to divide the land into long beds, sloping them to a ridge along the middle ; along the ridge the water channel is cut, and the water overflows both sides. These methods of overflow pre-suppose a Jarge supply of water to efficiently cover the surface of the ground, and are only suitable for fast-growing crops, as rye and grass land. These methods are usually applied to the disposal of sewage, as the repeated application of the sewage effectually precipitates and filters all impurities fro'm the water. The majority of crops will nob stand such heavy and continuous apolications of water, bub yet are benefited by" limited applications. For this class, pressure is required, and good pipes or troughs are laid o%'er the beds furnished Vifch°numerous small holes, through which the water is driven, falling like rain over the surface of the beds. The pipes are also laid under the ground, so that perfect subsoil irrigation may be carried on during the heat of the summer sun without scorching the plants. All these methods are largely adopted in the fruit-growing regions of the United States, bub would prove too expensive for any of our small farm 3. Especial care must be taken in preparing land for irrigation so that all inequalities of surface are removed, otherwise there will be an uneven flow over the surface.

TOWN SEWAGE. The disposal of the sewage of large towns has engaged the attention of our engineers for a considerable time, and has in many places proved a commercial success, whilst in other towns a great yearly loss is entailed in carrying out the plan. But whenever possible ic is required to be carried out in England as the only perfect method of purifying the sewage and rendering the eflluent water from the farms sufficiently pure to pass into the rivers. The mode of treatment is substantially the same as already described. The sewage is brought on to the land and retained first in a large settling tank or series of tanks, which get rid of a great portion of the solid matter. These settling tanks-are a necessity, otherwise, if the sewage Sowed straight on to the land, the amount of solid mud would soon cover the surface of the ground, and render downward filtration impossible. The farm is usually divided into two parts ; one part is devoted to crops requiring only intermittent irrigation, whilst the larger portion is cropped with ryegrass, which -v. 11l always take a continuous supply of sewage. Thig grase land is again divided into ten or twelve parts, each portion sufficiently large to take all the sewage for one month. By that time a heavy crop of ryegrass will be ready to cut. This crop is allowed to grow a week or so after the last of the irrigation has been applied, so that it may become quite sweet and clean before cutting. The "sewage carrier drains" for these crops are - mostly constructed with semicircular glazed earthenware troughs, which act in a more perfect manner and retain their level better than

earthen canals. This growth of ryegrass is generally a profitable crop, being always bought up by the dairy farmers of the district. IRRIGATION" ON SMALL FARMS. Having sketched out the general conditions of irrigation, I will now consider how it might be utilised to the best advantage on our small farms and uneven ground. We have a large rainfall, and the first consideration is to store some of the water for summer use. To this end I would recommend that well puddled banks should be made across the hollows at the heads of creeks and springs on the highest parts of the land. There are very few farms about this district which are without one or more depressions available for reservoirs. A bank five feet high in the centre, and forty feet long, enclosing a triangular space 100 feet to the apex, would contain somewhere about 32,000 gallons of water, A wooden or earthenware pipe must be laid through the bottom of the embankment, furnished J with a valve to regulate the flow. This water would be available for irrigating all the land below the reservoir. It does not require much knowledge to see what an immense value such a store of water would be, say, to a strawberry garden. In conjunction with, and near to the reservoir, a large tank should be constructed, and kept filled with water from it, and into which all animal matter should be thrown, so that by decomposition and fermentation a strong lye is being continually made. This tank should have an outlet regulated by a valve into the conduit from the reservoir, so that the irrigating water would be fortified with liquid manure in any proportion thought desirable, the lye tank being further fortified by that chemical ingredient most requisite to the crop under trsatment. Such a scheme is within the scope of any settler, as the chief i-equire-ment is labour only ; but great care must be exercised in making the bank to excavate a trench first to sound ground, and fill in again with well puddled clay to prevent leakage. The lye tank may also be lined with well puddled clay in the same way, as, being always kept full, there will be no cracking. It is very different to condense into the short space of this paper all that I would like to say, but trust that these remarks will lead to some useful results, and that in overcoming the uncertainties of climate we may bo able to procuie certaiu and abundant results in our produce. I must claim the indulgence of my audience for this somewhat fragmentary sketch, which was meant to be filled up and connected with blackboard illustrations, but illness preventing my reading this paper, the illustrations and remarks thereon have necessarily been absent.

The death of a horse from hydrophobia is reported as follows :—The British Board of Agriculture lately made inquiries into a case of hydrophobia of a very extraordinary character that had occurred at Dover, resulting from the injuries inflicted by a mad dog seven weeks before. Among the known injuries which the dog inflicted, it got into a stable and bit a valuable horse. Every precaution was at once taken to protect the horse from rabies, and large pieces of flesh were taken out where it was bitten, and the wounds then cauterised. The animal remained under the care of a veterinary surgeon until Friday, when ifc was allowed to do light work. On Saturday the horse was noticed to be strange, and it " barked" once or twice. It was taken home and put into a stable by itself, and rapidly became worse, dying rabid on Tuesday, after suffering frightful agony. The animal displayed all the symptoms diagnosed in a. human being. It was terrified at the sight of water, even in the early stages, and barked and snapped like a dog. It eventually killed itself by crashing its head against the floor of the stable. The New Zealand waterproof clothing manufactured by Hallenstein Bros., New Zealand Clothing Factory, is . undoubtedly the most thoroughly reliable yet introduced to the public. This excellence arises from the minute attention paid to details of manufacture, thereby ensuring the greatest durability in every part of the various garments. Special sizes and shapes iu coats, capes, leggings, etc., are made to order at short notice.

To Darken Grey Hair.—Lockyer's Sulphur Hair Restorer is the quickest, best safest; costs less, effects more than any other. The colour produced is most natural JLockyer's Sulphur is the only English Hair Restorer universally sold.