THE ESSAYIST.

Oamaru Mail, Volume IV, Issue 878, 7 February 1879, Page 2 (Supplement)

THE ESSAYIST.

TRKJOATION. '!•>■ fcn-ating upon a subject ot thJ9 nature- it wilt I hi neuessory to ttesuribu—first, what watuf 'S * second', its relation to plant*; third,. t« 8 mtneratogical significance ; fourth. its properties natter heat; fifth, drainage;

sixth* irrigation ; seventh, tow and when it may be applied with profit in Waitaki t.Wn ty ; eighth, the cere it*, herbage, fraits, and timbers to which tt form* the great vital principle: and tastty. its feasibility on » grand scale for other portion of the Colony. Water, chemically speaking, is composed of on« part of e*ygen gas and twt> ports of hydrogtsft gas. thus- every 9tb\. of watst eontains Sfb. oi osygen and lEb. of hydrogen. Water enters into, alt batata! combinations. from the human frame tmthe. rock formation on which the earth's erttat rests. Thus a hmty weighing 13411!*. loses IMb. of water by the process of evaporation, which make* ' water a» iadispenaabte t» the animal kingdom [as it b to that of the vegetable world. I fence ■it follows that a* man is» the head of etea- • tion. thii* relation snttst be borne o«t through the whote of creative economy. Water is i tuinid at the common temperature : tt freezes* 'at 32* Fahrenheit, ami boits at 212'; it be|wm«» gaseous- after passing the tatter degreebut recovers its liquefaction on an excess ot . temperature in the one instance, and «n a decrease of it in the other. Water, however, is Seldom found pace, and it often happens that the most sparkling and limpid is most loaded with minerat salts and other foreign bodies derived from the soil or rock formation from whence it springs. Even in the cast} of rain water, which is distilled in the clouds, imparities often oecxtr, which are ■ taken up in its passage through the air. Jn this Way water becomes- in part impregnated with those acids so necessary to the production of th« Vegetable fabric;, while in part it obtains them from the soils on which it Halts ami in which it becomes absorbed. As water reailily combines with *U solublesubstances, it follows that it is an absolute necessity to the production of the plant, and here heat becomes the agent by which much- of th« food material required by vegetation obtained., ft has been found that in proportion to the depth be tow the earth's surface the heat increases, and it has also, been found that water has a proportionately greater solvent power the greater its depth is below the surface. The theory is that minerals, or rather their compounds, are held in solution at a certain distance beneath the earth's crust owing to the action of heat upon aqueous vapour, assisted by carbonic-, nitric, and- sulphuric acid's. The great masses of Maori stone that are to. be- seen I'scattered about the ranges in the interior evidently owe tlievr origin to this eausp. combined with volcanic action. It is from these 'acids and heat, acting on organic or inorganic substances in the earth that plants derive the -greater portion of their structure and properties. Sitar heat. then, is to the moisture of the soil in, the production of the plant, what natural heat is to* the creation of the mineral kingdom. Thus water assimilates with carbonic and nitric acids, and these acids combine- with substances which in pure j water, owing to their absence, would remain in a neutral state :. for esamptc, nitrate- of potash., which is compose.!; of -ItJ-tJ potash and 3a'4 of nitric acid, and is in part derived from felspar, a mineral composed of silica, alumina, potash, soda. time, and iron. Xow„ it luus been found that both phosphoric and sulphuric acid also enter into the food of plants by means of water. The very important function water is catted upon to. fultil in the economy of nature may readily be seen. Drainage is, however, alt important in connection with a wholesome supply of water, because it is requisite that solar tight and heat should penetrate into the soil. anil it is evident that if a constant current ft moisture is rising from beneath the sod caused by- the accumulation of water bvtow it, the light and heat wilt be elf.rttiatly excluded. The plant food atso becomes too much diluted, so that the plant is twt sowed nourished, besides which the presence of so much water in the leaf and stern tend tf> keep down the temperature, and. when the sun's heat strikes it. increased evaporation takes place, and- a lower natural heat is the consequence, so. that the chemical changes on which its growth depends proceeds with less rapidity, but by the removal of alt superabundant water the physical properties of soiU are remarkably improved. IVadty drained tands become close and compact, excluding tin? air from the roots of plants, the access of which is one of the most important elements in the healthy production of alt vegetation. Drainak'e provides an outlet for this erccess of Water, and as it pcrotates downwards it carries with it the air from the surface. This becoming fixed in the pores of the soil assists in causing the. germination of the e-vpuusiott of the blade ami stem, and the maturity of the ear. Stiff day soils, when freed by this process from water, become more friahte. and when welt sub-soiled more mellow and porous, so tha" the roots of plants can find their way easily iu all directions. Thus the woody fibre, either existing in the soil from a tong period of natural production and decay, or added to it in manures, becomes doubly valuable-. When flooded with water, vegetable humus- either decompose* very slowly or produces chemical reactions which have, the most injurious effects upon the plant. Thpresence of air. on the contrary, causes the vegetable matter t<> decompose rapidly, producing carbonic acid in targe quantities, and supplying other food constituents to. the plant. Again, where water lies in sandy soils, it is a certain indication of a city formation below - hence the necessity of drainage in that ease. Thus it will be seen that there exists an absolute necessity for a thorough system of drainage to bring about the sood effects resutting from irrigation. The introduction into and free use- of the steam plough in Otagoand Canterbury will bring about many good restttts. and aid materiatty in the- draining- of" lands.

tight lands having a large crpranttty of ; shingle in them. »»«h as those laying l>c'tween t!u« intake of the Oam-i-tt water'work.* and the eastern bcmndary sea of fftp«lUi<» are of » etasa whit: ft t-ottld he made to ■ prodrug splendid returns from a;system of euttivatinn tinder irrigation, as they would not rcntrffe expensive drainage work* beuanse of their porott* nature-. In fact they are-exactly simitar to those lands whteh arc so reproductive under irrigation in Chili. The proprietor* of this targe extent of almost uncultivated and barren property should enter into an arrangement with the Oama.ru Municipality for a direct water snppty from the intake or any of the locks atonsj the course of the race. The ({ttantity of water available for irrigation pttrpose* troiiii this source is e»(tial to 1000 cubic feet per minat»v—a (.[Kantity sufficient to irrigate the whotw of the country enclose*! by the boundaries of the race, including eastern Fapakaio to the sea. and the northern to the Waitaki River, i'hanivet* cat at a ittstnnee of foar nutes apart. intersected by branch ttitch.es supplying the variotu fields is the usual method of procedure. It » neceasary £hat the bottom of these ditches should Im> at a lower level than the depth of the land Batter cultivation : ttnu land plotighcri a foot deep would require drain* of three feet, so as to prevent the flooding of the land after swt«*ati®n had taken place. Allowing that ta« (juantity of water brought on to the

land is nine inches in diameter in the ditch it would allow of nine inches of drainage level and enable the soil to free itself so much the more readily. The quantity of water required per acre is greater than in Victoria on account of the difference of climate. The price per acre for the irriga- ■ tion of the Awamoka and I'apakaio plains i would not exceed 5s for water, while the j cost of construction of channels and branches per aero should not exceed in the \ aggregate more than I*s. If for this outlay i the farmer can secure an indemnity against : drought, sonr land, and weeds, and increase the value of his property five or six time fas in similar cases in other countries), he well be well repaid for his expenditure. It may Ire argued that irrigation will not avert hot winds, but on the other hand the cultivator can sncccaafully plant eucalyptus, wattle, willow, brown ash, weeping elm, and poplar along the kinks of his main channels, which, if constructed across the course of these wind*, will in a few years produce a strong and exceedingly useful shelter against their withering effects, besides creating local rain attractions, securing the i banks of his channels, anil giving him a considerable yield of useful timber; and all this withont injuring the crops beside them, because they are secured a superabundant supply of &ui%l life. What a different picture the Awamoko |and I'apakaio plains would present if laid ! off in belts of trees two miles apart, each double line of timber being intersected by a channel of running water. The effects of irrigation combined with shelter and drainage are at once apparent to the traveller in those countries in which the system is gene ! rally adopted. Just such lands as the rough j shingly Waitaki intervales, and those of the | < 'auterbnry Plains, become in I'crti and jl'hih rieh with verdnre.i Plantations ! orchards, gardens, vineries, grass lands, '• and com fields, meet the eye in ever}' dircc- ; tion where irrigation exists ; while on the I other hand, in unirrigatcd districts, bare, i barren valleys, covered with scanty vegcta- : tion. stunted acacia and cactus take their ' places. In Otago we have a few similar {examples of its fertilising effects. At the i iHmstan. the orehard garden of Mr. Feratid, I situated aboiit two miles from Clyde, was jahont sixteen years ago a howling wildcr- ' ness of sand. This gentleman applied for ami obtained a small area of this waste tmder ' the agriealttiml lease system, and obtained a right to a small >|fiantity of water which he brought down from the higher lands to his garden site. Having planted a hedge and raised a shelter wall. Mr. Feratid laid the garden off in fruit trees of all descriptions including grapes, and had the satisfaction tive years afterwards of being able to supply a considerable anionnt of most delicious frutt. His yield has been going on increasing steadtlv up to the present time, mid the example set by him has caused numbers of gardens to spring into existence on both sides vi the t'lntha Uiver. where the surplus water of races brought into re.jui.-ition enabled the miner to create for himself a tittle Kdett "f fruits and flow.-rs. The frust raised on the l.'lutiia exceeds, for richness of ttavor and size anything hitherto produced on the eo.tst. I!rape.-* yield tine clusters ill the open air. Their vines are nurtured by a plentiful; supply of water, and they receive shelter from groves of other fruit trees and the shady poplars. With what pleasure may one stand under the i[iliveriiig leaves and listen to the murmur of the water as it pas.s.'.-t along its stoney bed at one's feet. How refreshing the s>parklc of its waves : how life giving its powers. Step aside for a few yards, and you enter again upon barrenness and scraggy nature just as it was before the hand of man was laid upon it to cultivate, beautify, and water it. There are certain theories given for the irrigation of crops, fruit trees, and plantations. For instance, one general rule may be adopted to insure success, provided always a drainage system be secured. It is this. When the crop is clear of all danger of late frosts, and when it is in full flower, drench lands. leaving Nature afterwards to do the rest. As has been already explained in the first part of this article, if drainage properly instituted the land may be looked upon as thoroughly irrigated, and the crops will show for themselves in a very short period the immense advantages derived from the combination of these systems. The theory applies itself to all vegetation. Practice, however, lead.-; one to the conclusion that in the case of fruits, nearly. if not fjttite, all of them arc greatly improved by irrigation from time to time from the flowering epoch up to the time the fruit has attained its full form. just previous to the stage of ripening. With the apple, the application of water tt|» to that time r.tfords it a rotundity, firmness, and freshness of color, which it never attains without it, and when ripe, its shades and streaks of color are brighter, its flesh more mellow, and its flavor richer than if left to nature to finish it off, after irrigation in the flower only. A reason for this mav be obtained from the fast that the

appb? trv-a t«>vvs a wot soil beneath its roots, fi.ai.fta which it Jindoubtedly receives all Lh«r strength which nature sucks to impart tr> it from germination to fruition. It ha been found, also, that trees suffer Ics3 from American blight if watt-red once a month daring the above period. Stone fruits, again, arc much benefited l»y tliis treatnwat. especially at the time when the stone is forming, known to practical men l>y the dropping of the weak fruit. It must be borne in mind that at this time if this kind of fruit tress do not obt-.in a sufficient supply of water through their roots, the silicious substance required for the formation of the matrix which protects the seed will not be forthcoming, and the fruit will shrivel up and f .11 off. Take a plum tree, for instance, which is loaded with fruit, by close observation one may discover sickly specimens, which by a touch of the fingers immcdiatcly ttrop-f>!;. Again, another looks poorly, but is dimity set, while close to it another looks green and plump. Now, it is evident that the iwt has received the largest quantity of support from the trees, and that the want of a sufficient amount of plant food is the cause of the dwarfing of the other. Tliis is a practical proof of the efficiency of irrigation in the cultivation of fruit trees. This system of water culture is extensively adopted in Chili. The city of Santiago, its large ami very beautiful capital, and environs, receives its water supply from a water-race G5 miles in length. It is conducted into the city by means of large channels or open sewe-s. which are flushed twice a day to clear off the accumulations which arise from all sources. Smaller sewers intersect the main streets, and from these branches are run through the gardens, orchards, and yards contained in ever} - block of houses throughout its area ; by this means flowers, fruits, and ornamental trees are regularly irrigated or attended to as required during the maturing season. In the neighborhood of the city large fields of lucerne are cropped for eight mouths of the year under the water system, and it is stated that wheat

has been produced off other paddocks year after year, for an indefinite period of time solely by means of the proper application of irrigation. The soil of these gardens and that outside the city very closely resembles that found in Awamoko and Papakaio, the alluvium laying on beds of gravel and shingle, and affording natural drainage, but there is a good deal of difference between the climate of the two places. The parallel, however, is sufficiently significant to show the vast advantage derivable to an agricultural community from the construction of open water-races as against iron pipes, and that also the use any surplus water can be turned to, in refreshing, enriching, and beautifying private gardens, as well as irrigating those tracts of country through which its course may lay. In all the Republics of South America, Mexico, and California, irrigation is adopted whenever practicable. In Colorado, near the Rocky Mountains, it has been most successfully introduced, and land which formerly yielded nothing beyond a scanty vegetation, now give from 50 to 6'o bushels of wheat to the acre. It must be remembered that Kew Zealand has to compete in her future grain trade, with the United States, and to do so she must use every effort. Our farmers can afford to sell their wheat at lower rates, provided they can raise larger averages per acre, and they must prepare themselves for this emergency, as it is not far off. Irrigation was systematicallypursued in Egypt, a country which had attained a high state of civilisation and agriculture in the time of Moses. In Arabia it still exists. In Italy, on the banks of the Po, it has been carried on siuce the days of Virgil. Many of the other Italian rivers and streams arc still employed in the carrying on of this system. The first and most important step in irrigation is that of taking the levels, but this becomes comparatively simple when the ground lies along the banks of a stream, or is commanded by a waterrace. In all irrigation the general x>rineiple may be described as the supply of an abundance of water to every portion of the surface, and taking it off again with rapidity. The lields should be laid off in broad undulating beds, the upper part of which is quite level from one end to the other, and along which the supply channel is cut, all the supply furrows are fed from this source. When the water is let on it flows into the upper channels, till they overflow into the furrows, when the water spreads over the whole surface. To effect a rapid drainage of the iields a suUicient number of tile drains may be laid down, or where the ground is stony, deep ditches may be constructed and partially liiied with stones. At the bottom of the fields a ditch, protected by a lowbank on the irrigated side, is necessary to carry off the irrigation water and to prevent it from encroaching past the required boundaries. The supply furrows abut on this bank, and at the desired time openings may be made beneath it into the ditch, to allow of free percolation. The irrigation of pasture lands in England takes place during the winter, or about Christmas, and as our winters are very similar to those of the Old Country, we can follow their practice. During frost, when vegetation is suspended, if a current of water is allowed to pass over a x>asturc field, the grass will continue to grow. This fact may be observed anywhere in New Zealand in grassy crocks. When a thaw or mild weather sets in, the water must be shut oil", as too much moisture i.-; injurious to the plant. It follows that iiTisjatcil pastures, will at the first sign of spring produce rapidly, because their reproductive powers have not suffered from the stagnating effects of winter. This practice, by judicious management-, will afford two or three crops of grass in each season. Much, however, depends on the quality of the water: that of the Waitaki, however, should be admirably adapted for the purpose, and where shingly lands are cultivated, lucerne should prove most luxuriant. There is one L'reat thing in suitable water, and that is the fact that manure is never required in conjunction with tho cultivation of lands irrigated by it. It is hardly necessary to point out the advantage gain, d to the producers of stock either for the dairy or for the market. The whole of the low - lying lands along the banks of the Waitaki, much of which is a mere bed of shingle, might by the application of irrigation, be turned into a most fertile plain, while plantations of mims, poplars, willows, and other useful trees might be cultivated to protect the river banks from encroachment, as well as serve to protect crops from the wind. To New Zealand, in a national and agricultural point of view, there is no greater question than that of land-improvement by irrigation, as it involves the successful production of all agricultural crops, and that also of the spread over the country of forests of useful timber, together with the establishment and maintenance of our future commercial and maritime importance. Look at the vast tract of country known as the Canterbury Plains. Mark the efforts made in the way of agriculture, the dependence upon the seasons for the yield, the almost absolute ruin which must follow to the majority of small farmers, if two dry seasons succeed one another. Look at the great want of shelter they have to combat against, and you will admit, with me, that without irrigation the Canterbury Plains must relapse into a sheep walk. By means of it on, the other hand, what would be the result? A magnificent plain, one hundred miles long, by an average of sixty miles wide, would be converted into one vast extent of fields of grain, green and luxuriant pastures, lands rich with root crops, gardens of blooming flowers, orchards filled with mellow and luscious fruits, and forests whose shelter and useful timbers, and rain attraction would contribute in no small degree to the health, fertility, and wealth of the whole Colony. Nor is this an overdrawn picture, for there are many examples to be adduced of such results from irrigation in other countries. These Plains are naturally watered by four rivers, namely, the Selwyn, the Rakaia, the Ashburton, and the Rangitata. Very large landed interests have been invested in them, thousands of pounds sterling are staked on their present and future productiveness. Irrigation alone will save the agriculturists of the Canterbury Plains.