IRRIGATION.

Press, Volume XII, Issue 1579, 28 November 1867, Page 2

IRRIGATION.

The following interesting paper on th>s advantages of irrigation in gardening opera tions was read by Mr Chudley at the last monthly meeting of the Horticultural Society : — Of all the substances which concur in the vegetation and growth of plants water is the most essential. Without moisture the seed cannot germinate, nor can the plant receive nourishment. Hence, in a climate such as this, where summer rains occur only at intervals of months in some instances, and'where the soil is dry and parched by continued evaporation, no verdure exists except where springs or rivers supply the want of moisture. The warmer the climate, and the- more rapid the evaporation, the more luxuriant is wJ$

tnere he an abundant T 1 of water. This circumstance has sugplarrof diverting stre:mrrTnid-ron-f ting them in channels:to fertilize as great xtent of lard as possible. In China and in as in' Egypt, ingenious "modes bf 'Serin* l'»° s haTO Wn afi:, P ted from * h * t remote ages. No expense has been Soufibfe"'too great to seenre a supply of ter n n< * t() distribute it in tho most *flvatitageou« manner. It seems that where there i" g reat nPnt in t,ie air w,, ter lone-«"» m W I ? the necPfmr y fon<l for ,h «' wtli of pants. It- is probable that the parts of the atmosphere are more C «ilv separated and made to enter into new * om binations with those of water in a high + mperature than in a lower, or that the leaves d green parts of vegetables imbibe wah-r f° a gtate of solution in the air, and that in this state it is more easily decomposed. Atjpherie air and water contain all the prin-cipal-elements of vegetables, viz, ozygen, hvdro'en, carbon and nitrogen; the remainder are either found in the soil or diffused through the water. Manures seem to act crincipally as stimulants or re-agents, and are enJge lyes composed of the same elements— iher a l * no u * e un ' eßß diffused or dissolved in water; but when the water is imprecated with aniiml or vegetable suhetances the effect is far greater ami more rapid than when the water is pure. Water has also an important office to perform if we admit the principle discovered by Hacaire.- that plants reject through their routs those portions of the sap which are the residue of its elaboration, and which are of no farther use to the plant, but rather injurious if they are again imbibed by the roots. Plants seem to require the removal of their excrements as animals do when tied up in stalls or confined in a small space. If this is noteffected they suffer and contract diseases. Ihe percolation of water through the soil is the means which nature has provided for this purpose. Hence we can readily suppose that the mere washing of the roots has a beneficial effect, and to this in a great measure must be ascribed the fertilizing effects of pure and BC-ft running water. If water stagnates and jjevmorated, and the noxious water held in solution remains in the *oil, all the advantage of irrigation is lost, and the better kinds of grasses are succeeded by rushes and coarse sqaatic plants, as may be seen in all marshy spots. The circulation of the water there fore appears to be as necessary as its presence, and provided there is a sufficient supply of a p-oper quality, the more porous the soil, especially the subsoil, the more vigorous is the vegetation. It is on this principle alone that we can rationally account for the great advantage of irrigation in those climates where rain is abundant, and where the soil which is most benefited by having a supply of water running through it is of a nature to require artificial draining as an indispensable preliminary to being made fertile by irrigation. By keeping these principles in view, great light trill be thrown on the practical part of irrigation, which, having been long established by experience before these principles were thought of, depends not on their correctness but only confirms their truth. The whole art of irrigation may be deduced from two simple rules, which are : first, to give a sufficient supply of water during all the time the plants are growing ; and secondly, never to allow it to accumulate so long as to stagnate Garden irrigation is a subject of great interest not only to the gardener, or the owner of a garden, but to all who trade in or consume garden produce. That irrigation has been practised: from very early times we know, for Holy Writ tells us of man turning the water wheresoever he would with his foot. And in Italy, to which climate that of Canterbury is said to be something like, the admirable system of irrigation which has rendered Northern Italy the most fruitful country perhaps in the world was established in very early limes. It was during the flourishing period of the Lombard Republics, about, the era" of our Norman and early Plantagenefc kings, while the greater part of Europe remained yet in a state little short of barbarism, that the design was conceived and executed of this great national work. From each of the lakes that occupy the lower declivities of the Alps, and receive the waters of their innumerable springs, issues one principal canal, which as ; «t descends is subdivided into a multitude of smaller channels, visiting every district and even every individual ifield, to each of which the water is admitted at pleasure by sluices, and having performed its office passes off by another cut to the lower land, till it ultimately reaches the Po, which carries the whole drainage of central Lomhardy into the gulf of Venice. The banks of these canals are mostly planted with willows and alders, over which are frequently seen ro«s of tall poplars. The principal canals belong to the Government, the smaller ones are generally the property of individuals, who let or sell the use of the water at so much per hour. But garden irrigation with us, or at least in the neighbourhood of Christchurch, is at once simplified, and brought within the reach and placed at the disposal of all by means of artesian wells—the one grand adjunct to Christchurch which has improved the health of its population so much as nearly to have eradicated the local fever, and greatly diminished the practice of the medical profession. To show the indefatigability of the French in the matter of their water supply, it may be interesting to quote from the " Penny Magazine" of the Society for the Diffusion of Useful Knowledge, November, 1841, a short account of artesian well-boring at Grenelle, near Paris. After describing the geological basin of Paris, it says : —The necessary works were now commenced with boring-rods, about ninejrards long.jittached to each other, and which could be raised or lowered by. mechanical means; and an ingenious method was adopted for giving them circular motion. The diameter of the bore-hole was about six inches. Th?"instrument attached to the end of the lowest boring-rod was changed according to j the different strata which were successively reached, the form adapted for passing through thesofter materials of the surface being unsuitable to bore through the chalk and flint, a hollow tube being used for the former, while the latter was penetrated by a chiselshaped instrument. The size of the rods diminished in proportion tothedepth.andasthe Subterranean water was not reached so soon as was expected, it became requisite five several times to enlarge the diameter of the bore to admit of the work being successfully continued. Accidents occurred also which tried the utmost patience of the projectors. In May, 183 1 ?, when the boring had extended to a depth of 418 yards, the hollow tube, with nearly ninety yards of the boring rods attached to i f , broke and fell to the bottom of the hole ; Md it was necessary to extract the broken parts before any further progress could be made, and the difficulty of accomplishing this may be conceived when It is stated that the different fragments were not withdrawn until the Japse of fifteen months. A description of the, ingenious mode by which this was effected would be too technical for our work. Again, in April, 1840, in passing through «balk, the chisel attached to the boring-rod fewame detached, and before it could be recovered several months were spent in exCav&ttng around it. A similar occurrence created an obstacle which impeded the work for tlirea months, but instead nf being with' drawn tha detached part was driven literally into the stratum, which happened to be gravel. At length, in February, 1841, after eight years labour, the rods suddenly descended several yards; they had pierced the vault of the subterranean waters, of which M. Mulot, an experienced geologist, had been so long in search. In the course of a few hours the water rose to the surface, and discharged itself at the rate of 600,000 gallons per hour. The depth attained was six hundred and two yards, or about three time the height of St. Paul's, t-ondon. The pipe by which the water reaches i»e surface has recently been carried to a ° p ight nearly on a level with the source of supply. The pipe, as it rises from the ground, a nd the scaffolding which support it, are shown in tho cut. A t present the water Sows into a circular iron reservoir at the top of the scaffold, and it is thence conveyed by another pipe to the ground. Ihe water is of good quality, and well for culinary and domestic purposes.

There is no fpar of the supply proving deficient, as it i» derived from the infiltration of a surf-ice of country nearly 2'">o miles in'diameter The arte-iin wells of Elbeuf, Tours, and Rouen, which were formed many years ago. flow in an invariable volume. The an--ient artesinn w.ll at Lillys, in the Pas de Calais has for above seven eon tunes furnished a constant and equable supply When tho source nT siipnlv is K-ss extensive these wells may he subject to variation, bui. the probability of thi* •nay generally h-» foreseen by thegedogist and the engineer. The opportunity of ascertaining the temperature of the earth at great depths was not negWted dii'ing the progress of the work nt Grenelle. Thermometers at the depth of thirty yards in the wells of the Paris invariably stands at 53leg. Fahrenheit In the ' well at Grenelle the thermometer was 7-l.leg. at the depth of 442 and at 550 yards it stood at 79deg., the depth attained being 6002 yards the temperature of the water which rose to the urf-ice was 81-b-g, corroborating previous calculations on the subject. Now that the patient lahour of so many years is brought to a close, our neighbours regret that it was not necessary to go to a depth of about 1000 yards for n supply, as the water would then have been nt a temperature of lOldeg., and immeI liately applicable to bathing establishments j und other places in which warm water is ! required. Fortunately for Christchurch an abundant supply is readily obtained at about, one-eighteenth part of the depth of the well at Grenelle; the temperature of the water at the depth of thirty yards appears to be nearly the same at both places. I have occupied your attention thus far in speaking of artesian wells, and you will understand them as "being the source, the fountain head whence the supply is obtained for the purpose of garden irrigation, that being the only practical means at our command. The well should be placed so as to have its fall from the highest level in the garden, the size of'pipe used to be in proportion to size or extent of land to be irrigated. In laying out new gardens, or altering old. it is recommended for the kitchen garden to carry the water in onen channels along the side of the walk, the main or central walk fo be raised slightly higher than the borders, which are to have a gentle slope on either side. By this arrangement, and using only mother eartli for the conductor, the water can be diverted at any point at pleasure, a small groove at different intervals along the length of the garden conveying the nourishing element without any labour to the withering crops, and if nicely managed may be allowed to run during the whole night and for a number of days and nights in succession, with only occasional superintendence. A few dipping-places along the garden are of great, use and vory convenient, and may be formed by sinking old barrels in the line of the open gutter, and cutting out a few inches of two opposite staves so as to allow the water to fill it and then flow on its course. The barrels should be of sufficient size to admit with ease a two gallon watering pot. The great advantage of the open channel over the hose is that the water in pnssing along the former becomes airified and warmed before reaching thp plants. It is found that water so conducted on a warm day increases in temperature at the rate of about sdeg. for every chain in length of distance; and I am of opinion that to raise the temperature of the water still more before applying it to some garden crops would be very beneficial. This may be accomplished by forming a reservoir around the well to retain the water after passing through an ornamental fountain, and connecting the overflow with the open channel, or by fixing one or more largo iron tanks and filling them by means of a length of hose, and allowing it to stand in the sun, where it would become heated to a high degree, and would be suitable for watering cucumbers, vineries, pot-plants and any tender subjects. For orchard ground, and indeed large quarters of rough kitchen garden crops, and where the ground is of an open porous nature, sluices of considerable width around, or through such quarters, is the best mode of irrigation. The soil will by infiltration absorbsuffibientto moisten the whole to an incredible distance. In connection with the subject of irrigation it is necessary to consider that of drainage, nature of subsoil, and also the requirements of the particular crop so treated. Most crops will require but light watering, which it is necessary to perform by hand until they have acquired size and advanced so far in their growth as to need a larger amount of moisture than our summer weather usually affords. For instance, fresh-planted cabbage, cauliflower, celery, or peas and beans, if requiring to be watered in their early stages of growth, are better supplied from the watering-pot than in the manner above detailed, for if saturated to any great extent before having attained a considerable amount of foliage and consequent large extent of root, the soil will become so set when the water is turned off that the plants or young seedling will be checked and greatly injured rather than benefited. Therefore it is that due judgment must be exercised and caution used to apply at the proper season and liberally that which would injure our crops and make of no avail our labours if applied without thought and without system. One chief point to be attended to is that when irrigation is commenced with a crop the ground must not again be allowed to become too dry before applying water, so as to maintain a sufficient moisture in the soil, otherwise the plants will suffer more than they would have - done had they not been watered at all. I find it helps greatly to keep the blight in check if cabbages are watered over head with a good coarse rose from the watering pot, and in the heat of the sun ; or a sprinkling from the hydropult will give them a shower in a very short space of time that will cause the blight to leave them in a fright I wish to call especial attention to this useful garden engine ; owing to its portability it is more bandy than the wheeled garden-engine, and being much more powerful is superior to the syringe A jet from it will completely drown out the blight from the apple trees in less time and much more effectually than the application of any compound or brush, and without in the least injuring either tree or fruit. My own trees so washed are perfectly j clean, although the unsightly knobs tell too plainly of their late visitation. I do not maintain that one washing will clean them, but that an occasional shower applied with some force and thoroughly to all parts of the tree is the very best and cheapest mode of keeping the pest in the check. For washing the green fly off roses in the open garden, or watering cucumbers, the vinery, or sprinkling pot plants, or washing windows, it is par excellence the machine ; where there are many trees, and the water is not convenient, it is better, but not absolutely necessary, to have a second person to bring the water to the one using it. Irrigation with manure water I consider to be impracticable, except by hand labour. Liquid manure may be obtained by various means, as steepi- g the powerful solid manures, and using the water ; or, where it is ready at hand, the drainage of slable and other manures. The pig is very useful to the gardener, as by converting the garden refuse into manure, and adding to its own proportion at the same time, it is turning to account what would be otherwise wasted. For the purpose of combining cleanliness with utility tilt) animal mm be nccomnioriared within a comfortable stye, with close-boarded floor, laid with a little slope towards the front, which should face the east, a hole being dug in Die ground at a couple of yards distance of a sufficient size to store the manure until required for use The manure is thrown into this once or twice a week, and a few buckets of water will make all clean and cool, and Mr Pig will grunt his delight and satisfaction—a small gutter or a few drain tiles takes the water into the hole along with the solid manure—an old barrel, with both ends outplaced :n one corner and raised a little from the bottom will act as a reservoir, and furnish the gardener With liquid manure at no cost and very little trouble. Little lias yet been said regarding the flower garden or shrubbery, and this may be considered as secondary in importance to the more useful and more substantial department of the kitchen garden ; at least it is so now, in these economical times. For the use of the flower garden tbe hose is recommended I as being less objectionable than the open

channel; and where grass or extensive flower bed are to he wa'ered the ho->e is by far preferable fo any other means! Tanks or cisterns /nay be placed in such positions as to he bid from view by the shrubs already in suitable places, or others to be hereafter planted • lanien irrigation is a subject hitherto neglected, aud a gre:it deal more may be said >n-the matter than I should like to venture on this evening, as y*"ir pitienoe would be tried fhroiliih my tediousness ; but. if tedious, it !»hs 'he good q-iahty of not being dry : and not hems; desirous of exhausting either myself or my subject, I will now leave it to your consideration, li >pi"g that the most, pleasant portion of the evening is now to commence. 1 have but one request to make, and that is to a«k you all to allow the discussion to flowfreely in straight open clv4mi-!<.