The Culture of Citrus Fruits under the Climatic and Geographical Conditions Pertaining to the Murray Valley; by Franz Rudolf Arndt (1919)
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CULTURE ./CITRUS FRUITS Conditions pertaining Murray Valley, F. R. ARNDT ADELAIDE: Var.don & Sons Ltd., Printers, Grcte Street, 1919. _. ; _ I
The CULTURE rCITRUS FRUITS Under the Climatic and Geographical Conditions pertaining to the Murray Vailey. BY F. R. M ARNDT Author of"Fruitgrowing under Irrigation," "Possibilities of Irrigation," etc., etc. COPYRIGHT BY THE AUTHOR ADELAIDE: Vardon & Sons Ltd , Printers, Grote Street, 1919.
PREFACE During the expansion of the citrus industry thathas within recent years taken place along the MurrayValley the absence of any book of a general naturedealing with the culture of citrus fruits under localconditions has often been a considerable .handicapto new growers in the laying out and managementof theirplantations. It with the object of isattempting to remedy this disability that this work ispublished, and it is the authors hope that newand prospective citrus growers may find the informa-tion herein contained of some use to them. A considerable portion of the subject mattercontained in the following pages has been takenfrom the authors previous works from a pamphletentitled Orange Culture, published in 1914, and fromFruitgrowing under Irrigation, published in 1918.The whole of such extracts from these works as areherein incorporated have been revised, two newchapters have been added, and an endeavor madeto present the subject to the reader in a plain andconcise form. F. E. ABKDT.Berri, Eiver Murray, South Australia. 4th November, 1919. 416803
CONTENTS.Chapter. Page. I. The Murray Valley . . . V . . 6 II. Locating the Citrus Grove . , , 9 HI. Getting the Land Beady for Planting . . 12 IV. Laying out the Land for Watering . . 14 V. Varieties to Plant .. ... .. .. 1G VI. Planting .. .. .. .... 19 VII. Cover Crops . . , ., 23VIII. Irrigation . . . . . . ... . . 25 IX. Cultivation . . . . . . . . . . 31 X. Pruning .. .. .. .. .. 34 XI. Manuring . . . . , . .... 36 XII. Harvesting and Packing.. .. ... 41XIII. Diseases and Insect Pests ,., . . 44 XIV. Cost of Bringing a Citrus Plantation into Bearing on State Irrigation Areas of South Australia 49
CHAPTER I. THE MUKRAY VALLEY. The portion of Australia supplied with the largestvolume of running water is the Murray Valley. TheMurray has its source in the Snowy Mountains, andfed by its tributaries, the Darling, Murrumbidgee,Goulburn, Mitta, Ovens, Compaspe, and Lodden,in normal years brings down large volumes of water,which, with the exception of the comparativelysmall quantity utilised for irrigation purposes, isdischarged into the sea. . The greater portion of thecountry through whichthe Murray, Darling, and Murrumbidgee flow hasan average annual rainfall of about 10 inches, whichrenders the growing of crops without irrigation asomewhat hazardous operation. Owing to the fact of large volumes of waterflowing through dry, but, on the whole, fertilecountry, the Murray Valley is, in the natural courseof events destined to become -to a far greater extentthan it already is the seat of the chief irrigationdistricts of the Commonwealth. For their suitability to fruit culture the irrigationsettlements of Mildura, Merebein, Eenmark, Berri,and Waikerie, all of which are situated along thebanks of the Murray, have long been noted. The kinds of fruit chiefly grown consist of variousvarieties of the grape vine, such as the sultana, zantecurrant, and Gordo Blanco, different sorts ofdeciduous trees, like the apricot, peach, and pear,and Washington Navel and mandarin oranges.
The Washington Navel thrives better here thanelsewhere in Australia, the conditions favorable toits growth appearing to be practically ideal. Man-darins also thrive well and bear heavy crops, whilethe Valencia Late is also proving a profitable variety. WATER SUPPLY. With the exception of the Yanco irrigation area(Murrumbidgee), which is watered by gravitation,the various Murray irrigation settlements aresupplied with water by means of pumping plants,lifting the water into the irrigation mains to heightsvarying from about 40 feet to 130 feet. Water is applied on most of the irrigation settle-ments in four or five irrigations, ranging from Augustto March for deciduous trees and vines, but forcitrus an additional irrigation is usually given duringApril or early May. CLIMATE. The climate of the Murray Valley is hot and dry.The rainfall, as before stated, averages about 10 inchesper annum, and is insufficient for fruit culture withoutthe aid of irrigation. The months of November,December, January, February, and March areusually hot, the temperature often exceeding 100degrees Fahr., and sometimes reaching 110 degreesduring severe heat waves. Hot, northerly windsoften accompany these heat waves. The nightsduring the summer months are usually cool. The climate during the winter, and autumn,early spring is mild. The days are usually fine andsunny. The night temperature sometimes sinks afew degrees below freezing point, but any considerabledamage to plant life from frost is rare. During September and October the equinoxialgales often blow with considerable force and per
8sistence,making it necessary to take precautionsagainst the drifting of the surface soil of the looser(sandy slopes. NATURE OP MURRAY LANDS. The land suitable for fruit growing along theMurray consists of two distinct sections the river:flats and the high lands. The river flats consist of alluvial soil depositedby the river in the course of ages. These flats are,on the whole, fairly level, but usually containnumerous small local irregularities, which have tobe graded off before the land can be planted. Thesoilusually consists of a variety of clays and loamsof a fairly heavy nature, which are often overlaidwith a layer of sand. The high lands generally consist of loose, sandyrises, which in their native state are often thicklytimbered with pine, mallee, and other bushes. Thesoil is generally a red, sandy loam. The depth ofsoil varies from about 2 feet to 5 feet, and is usuallyunderlaid with a loose, light-brownish marl. Landof thisnature exists by the thousands of acres alongthe Murray Valley.
CHAPTER II. LOCATING THE CITRUS GROVE. SUITABLE SOIL. Owing to the fact that citrus, as other varieties offruits, do not do equally well in every kind of soilor situation, it is first of all necessary to select apiece of land having characteristics best suited totheir requirements. Regarding the class of soil best suited for citrustrees, experience has shown that loose, rich soilswhich have perfect drainage have given the bestresults. This does not mean that citrus trees willnot grow on rather heavy land. On the Adelaidoplains, as well as on the river flats at Renmark andBerri, oranges and lemons do remarkably well onrather heavy clay soil ;but young trees are some-what difficult to start in such soil, and their growthfor the first three or four years is slow. The deeper class of soils of the Murray uplandsmay be said to be practically ideal citrus land.Land of this nature is, in its native state, usuallycovered with pine, needlebush, or big mallee, andconsists of a red sandy loam, from 3 to 5 feet indepth, underlaid by a loose, greyish-brown cal-careous marl. Local experience has shown that citrus trees donot thrive on land having limestone, either in theform of rock or rubble, within a few feet of thesurface, as such land is often full of salt, or on landunderlaid with a whitish, putty-like clay. The alkali problem is probably the most seriousdanger that the citrus grower has to face upon theMurray uplands, as such salts as sodium chloride
10(common salt), sodium sulphate (Glaubers salt),and magnesium sulphate (Epsom salts) are highlydetrimental to all varieties of citrus trees. There-fore, land likely to develop alkali trouble, such asshallow soils under 3 feet in depth resting uponlimestone, or upon a hard or tenacious subsoil, shouldbe avoided by the planter. However, as the presenceof alkalies in a soil is due to defective under drainageby choosing deep land, with a loose subsoil, nodamage from alkali trouble should be experienced.SITUATION NOT SUBJECT TO HEAVY FROSTS. Although, on the whole, severe damage to citrustrees due to frosts is but a rare occurrence on theMurray Valley irrigation settlements, there are yetcertain situations subject to comparatively heavyfrosts which should be avoided by the planter. It is a matter of common observation that frostsare the most severe in valleys, hollows, and lowareas, while the adjacent hillsides or elevated landsremain comparatively untouched. This is becausethe cold air from the hillsides, being heavier, drainsoff into the lower levels and settles there, while thewarm air rises to replace it. This interchange of aircontinues until frost occurs in the lower levels, whilethe higher lands escape.. A citrus grove should, therefore, never be locatedin a hollow, basin-shaped depression, or in a narrowgully. THE IDEAL POSITION. The ideal position of a citrus grove is on a slope facing the east, as experience has shown that the rays of the rising sun are less injurious to frostedplants than they are if the sun is some distanceabove the horizon before it strikes them while the ;slope of the ground will allow the cold air to drainoff into lower levels. Of course, a situation facingthe east, although desirable, is not essential for thelocation of the grove, the one thing necessary being
11that the plantation has perfect air drainage, so thatthe cold air can drain away ; and therefore a positionon sloping ground is the best. One thing the planter should be careful of, andthat to plant no belt of evergreen shelter trees isalong the boundary *t the lowest portion of thegrove. Such trees, being in full leaf in winter whenthe frosts occur, prevent the cold air from passingfreely away and force it back upon the plantation,thus causing frost on the lower portion of the grove.Should a breakwind be required along the lowerboundary, it should consist of deciduous trees. GOOD DRAINAGE ESSENTIAL. As ail varieties of citrus trees are impatient ofstagnant water about their roots, they should onlybe planted on land having perfect drainage, and,therefore, shallow soils, or very heavy soils whereonthe water stagnates, must be avoided by the planter. As one of the greatest drawbacks on an irrigationarea is the menace of seepage, land that is full ofhollows, or that has a heavy sub-soil, should not bechosen. Seepage is brought about by the irrigationwater running along the sub-soil and coming to thesurface where this sub -soil is shallow or where itmeets the surface of the ground. Blocks situatedon sandy rises which peter out on to clay flats areliable to develop seepage, which will show itself alongthe line just above where the clay and sand meet.Land that contains hollow, basin-shaped, depressionsshould also be avoided, for unless the sub-soil ofsuch depressions consists of deep sand, the waterfrom the surrounding higher lands will <oak intothe hollows and kill the plants it contains. A blockof land having deep soil of a uniform nature, with anot too tenacious sub-soil, and having an even slope,is about as good a proposition as can be obtained.
12 CHAPTER III.GETTING THE LAND EEADY FOE PLANTING. CLEAEING, FENCING, PLOUGHING. The expenses of clearing will, of course, vary according to the nature and density of the natural vegetation. Box lands, as well as pine and malleecountry, vary from about 2 to 6 per acre, ac- cording to the size and density of the natural growth.For the grubbing of the more heavily timbered landsgrubbing machines and tree-pullers are usually used,and on some of the Government irrigation areassteam traction engines are employed in pulling out.the trees and stumps. To protect the orchard from the ravages of rabbitsand stock it is necessary to enclose the plantationwith a good substantial wire fence, with 3 ft. wirenetting. At normal prices for material, a 4 ft. highfence, posts 12 ft. apart, four wires, and wire -netted,will cost about 60 per mile. After the land hasbeen cleared it should be deeply ploughed to loosenthe soil and to get rid of the roots of the nativetree which occupied the land. The cost of a first4eep ploughing will be about l per acre. GEADING. As it isessential for the success of an irrigatedorchard that there should be an uninterrupted flowof the irrigation water, all irregularities of the surfaceof the ground which would interfere with the waterflow should be graded off. Lands having any considerable fall, such as thegreater portion of the high lands, require but little
13grading, which will be mostly restricted to the re-moving of small bumps or rises. On no considera-tion should more soil be removed than is absolutelynecessary, as experience has shown that where fromsix inches to one foot of the surface soil has beengraded off and trees planted on the exposed sub-soil,that their growth has been slow and unsatisfactoryfor years. On the box flats and on other lands wherethere is but little fall, the grading has to be morethorough, as the slightest rise will stop the flow ofthe irrigation water. The cost of preparing the land for planting will,of course, vary with the nature of the land. On theState irrigation areas of South Australia, the Gov-ernment makes advances to settlers for grubbing,fencing, grading, and channelling up to 15 per, acre.Not every block, however, will cost as much as thisto prepare for planting, and 12 per acre may betake as a rough average.
14 CHAPTER IV. LAYING OUT THE LAND FOE WATERING. IRRIGATION CHANNELS. After the land has been grubbed, graded, andploughed, the next thing is to have the irrigationchannels put in from which the land is to be watered.The channels are usually made from lime or cementconcrete, but irrigation by means of reinforcedcement piping has within late years been introducedand given satisfactory results. The greatest care should be exercised as to wherethe channels are put down. Upon the position ofthe channels depends the length of the rows of treesto be watered. Experience has shown that in loose,sandy loam rows 5 chains in length are long enough,and that on no consideration should rows over sixchains long be watered in one section on this classof land. As on the loose, sandy rises, of which the irrigationsettlements chiefly consist, the furrow system ofirrigation is practically the only one that is used it fol-lows that the water is flowing for a considerable timepast the first trees of a row before it reaches the lastone, therefore, the longer the rows are, the longer willthe water take to reach the end. On very long rowsthe first tree will have had too much water before thelast tree will have had enough, and the top of theland will in time become water-logged, to the injuryof the trees. In any case, the surplus water will soakdown the slopes along the sub-soil, and should thisin any case come close to the surface of the ground,
15the water will corae up there in the form of seepage,bringing the alkalies contained in the soil with it,and killing the plants in the vicinity. Having shortrows means, of course, much channelling, whichgreatly adds to the first cost of the place, but it willpay in the long run in the ease with which the landcan be watered, and in the satisfactory growth ofthe trees. Another matterin which care has to be exercisedis to see that the channels are so situated that thegrade of watering is not too steep or too level. Onsandy rises a fall of one foot to the chain is suffi-cient, while anything under 4 inches to the chain istoo little. It is a mistake to water straight downsteep slopes, as the force of the water washes deepgutters in the land at the top. The washed-out soilcarried down by the water silts up the furrows furtherdown the slope, causing the water to spread over theland at that place, so that very little water reachesthe end of the rows. Where the land is hard, as on most of the flats,the grade along which to irrigate may be considerablyless than upon sandy rises, as the soil absorbs thewater far more slowly than is the case with thelooser land. The danger of watering along an almostlevel grade on loose, sandy land is that, through theporous nature of the soil, the water sinks in sorapidly that the top ends of the rows get too muchwater before the bottom ends have had sufficient.Unless the drainage of the land is excellent, such asystem of watering will, sooner or later, cause seepageto appear lower down the slopes. Thus it is notsafe to water with a fall of less than 4 inches to thechain on sandy rises from 6 to 9 inches being themost convenient grades.
16 CHAPTER V. VARIETIES TO PLANT. The Washington Navel is the most extensively!planted of all varieties of citrus grown in the MurrayValley. As previously stated, this variety thrives j-exceedingly well under the conditions existing alongthe banks of the Murray, and with the exception ofoccasional unfavorable seasons, is a consistent bearerof heavy crops of well-flavored and highly-coloredfruit. Being so well suited to the district, thisvariety is likely to remain the chief kind grown formany years to come. The Thompsons Improved Navel has also beenplanted to a limited extent, but whether it will boas profitable a variety to grow as the WashingtonNavel experience has yet to prove. The Valencia Late is another variety that has beenplanted to some extent within recent years, and isproving itself suited to Murray Valley conditions.This variety does not ripen until the navel crophas been practically disposed of, and althoughhardly of the best quality, comes on to the marketwhen this is bare of citrus fruits, and so realisessatisfactory prices. The varieties of mandarins that have given goodresults are Oonshui (early, but : does not keepwell), Dancys (highly colored, good bearer), Beautyof Glen Retreat (little later than Dancys, goodbearer). The lemons usually grown are Lisbon (heavy wintercropper) and Villa Franca (good bearer, ripenssome fruit during summer if autumn flowering isnot destroyed by frosts).
17 For the purpose of marmalade making the Poor-roan orange is grown to a limited extent. CITRUS STOCK. Another thing the planter will have to consider,and that is upon what stock the young trees arebudded. In Australia citrus trees are usually buddedupon Seville, sweet orange, and lemon stock. Ofthe three the Seville stock makes the hardiest tree,and American and Australian experience seems tobe at one in this matter. The Seville is not so liableto collar rot as the lemon and sweet ora.nge, and can,therefore, be grown on wetter land than either of theother two, and has proved itself able to withstandfloodings and to grow in fairly moist situations.The Seville as a stock causes slow growth to thevariety budded upon it, makes for a rather bushytree, and the fruit, although of good quality, issomewhat smaller than that grown either uponsweet orange or lemon stock. SWEET ORANGE STOCK. The sweet orange as a stock makes for a quickgrowing, vigorous tree. On a good, loose, loamysoil, where water does not stagnate aroundthe butts of the trees, and where the drainageis good, the sweet orange stock gives goodresults. It gives a large and vigorous tree, andinduces a good crop of good-sized fruit. Owingto a widely spread belief that the sweet orangeis more resistant to the effects of moisture and tothe baneful influences of many of the alkalies dis-solved by irrigation water, many growers prefer itas a stock to the rough lemon. ROUGH LEMON STOCK. As a stock, the lemon has the reputation of beingthe least hardy of the three varieties under considera-tion, and is usually held to be more liable to collar
18rot, impa/.ient of much moisture around the roots,and more likely to suffer from the attacks of alkaliesthan the other two. Therefore, trees on this stock should not be plantedon soil likely to be flooded by rain or irrigation water ;but will succeed on dry situations having gooddrainage. Bough lemon stock is the favorite stock for citrustrees at present used in Sydney, having practicallysuperseded the Seville and sweet orange for thatpurpose, and is there known as the "Citronella"stock. This variety has also been extensively usedas a citrus stock along the Murray Valley, and sofar has given good results. The rough lemon stock gives rise to a tall, vigoroustree, with large sized fruit, and trees budded upon itgrow very quickly and come early into bearing. In the writers plantation Washington Navel trees,budded upon sweet orange and lemon stock, wereplanted side by side at the same time, and in the sameclass of soil, and at the present time (eight yearsafter planting) not only have the trees on the lemonstock beaten the others in fruitfulness, but inquality of fruit size, thinness of rind, and sweet-ness as well. However, this position may notbe maintained in the future, as the trees on theorange stock steady down in growth and yieldheavier crops, but it bears out what appears to bethe general experience that the lemon stock .isconducive to early fruiting. Briefly stated, sweet orange and rough lemonstock may be safely used on dry situations havingloose soil and good drainage, while sour stock is bestsuited to wet land, or land likely to ba flo Deled.
19 CHAPTER VI. PLANTING. After the laud has been grubbed, ploughed, graded,harrowed, chauuelled, aud it has been decided whatto plant, the ground is next set out for planting. The length and grade of the rows of trees andvines necessary for their satisfactory irrigation hasalready been dealt with in Chapter IV. Where theland is hilly or undulating it is often impossible towater all the land of a holding with the same grade,therefore the orchard has often to be laid out in twoor more sections, each section having a differentgrade along which to water. This somewhat spoilsthe appearance of uniformity of the plantation, butwith our furrow system of watering this is oftenunavoidable, as the success of the orchard dependsupon its efficient irrigation, so all other considera-tions must give place to this. Citrus trees aro usually set out in orchard formvarying from 20 feet to 24 feet apart. As manyvarieties of citrus and especially the WashingtonNavel are of spreading habits, they should on noconsideration be planted closer than 20 feet. Thestandard distance for planting deciduous trees hasfor many years been 20 feet apart on the square,and many citrus plantations have been laid outaccording to this standard. However, in very rich,loamy soil, wherein the trees make heavy growth,their branches are apt to get too close to each otherwhen the trees reach maturity, thus interfering withthe cultivation of the plantation, and, therefore, inthis class of soil it is better to plant the trees from22 feet to 24 feet apart.
20 PEGGING OUT. After the grade and length of the rows, as well asthe distance at which it is intended to plant, hasbeen decided upon, the ground has next to be peggedout for planting. This is usually done by meansof a wire-planting line that has either metal or clothtags inserted at regular intervals at the distance atwhich the trees are to be planted. In using, theline is drawn tight, and a peg is driven into theground at every tag. Where the land is fairly level, or has but a gentlefall, the channel may be usod as a base line and therows go off at right angles from it ; but where therows, in order to have the correct grade, branch offfrom the channel at other than right angles, then theline drawn from the channel at the angle it is intendedto water should serve as the base line, and all othermeasurements should ba taken from this. Owing to mistakes made in the laying out of aplantation remaining for the orchards existence,those without previous experience should otain theaid of an experienced man to help them with thiswork. PLANTING OUT. Citrus trees are generally planted along the MurrayValley during the first two weeks of September.Planting during the month of May has something torecommend it, as it gives the trees ample time tomake new roots before the hot weather sets in.Trees planted in May have to receive a plantingirrigation, should be protected by hessian or othermeans from the winter frosts, and if the winter isdry, as is often the case, will have to receive a winterwatering. As the pumping plants of most of theirrigation areas are not at work during the wintermonths, the difficulty of obtaining a late autumn or"winter irrigation has militated against the autumnplanting of citrus, and makes September plantingthe easiest and safest proposition.
21 Citrus trees are received from the nursery inboxes packed in earth or damp sawdust, with thetops covered with hessian. If it is intended to pJantwithin a few days of their arrival, the trees, if theyare in good condition, may be left in the boxes untilplanting time, care being taken to place the boxesin a cool and shady place, the tops kept covered up,and ample supplies of water given to the roots andtops. If it is not intended to plant for some time,or if the leaves ^f the trees are limp, the trees shouldbe taken out of the cases and heeled in in a shadyplace. Plenty of water should be given to both theroots and foliage, and the tops left covered withhessian. Before planting the roots should be shortened backand all broken roots removed. In cutting back thetops it is not advisable to head the trees too low.Clean stems of about 18 inches are more desirablethan shorter stems, on account of the limbs of low-headed trees, being nearer the ground, getting in theway of the cultivator. Besides this, the fruit oflow -headed trees is apt to come in contact with theearth, and is therefore liable to be spoiled. Treeshaving long, clean steins should have their stemsprotected by straw or hessian loosely tied aroundthem for the first summer to prevent injury fromsun scald, which covering may be removed in earlyautumn. Trees that have been headed low in thenursery should have all drooping growth removed,and pruned to upward growing branches, and underall circumstances all unripe shoots should bo cut off. Citrus are best planted with an irrigation, thewater running along the furrows and being led intothe holes while the trees are being planted. Caremust be taken that the trees are not planted deeperthan they stood in the nursery-^if anything a littlehigher to allow for settling as citrus do not do wellif deeply planted. When taking the trees out to be planted, the rootsshould be kept covered with a damp bag or piece
22of hessian, or carried with the roots in a tub ofpuddle until they are planted. Nothing is soinjurious to young citrus trees than to have theirroots exposed, even for a few minutes, to the in-fluences of sun or wind. If the trees are planted before an irrigation, theymust be each given a bucket of water immediatelyafter planting, and the irrigation should follow in acouple of days. A good cultivation should follow,especially close to the trees, which* should be donewith a forked hoe or rake to avoid cutting the roots.
23 CHAPTER VII. COVER CROPS. Crops of annual plants, such as cereals and legumes,are often grown in tlie plantation, and are usuallydesignated as cover crops. Cover crops are gener-ally grown for shelter or for green manure, or forboth. If situated on sandy land the soil of a newlyplanted or young orchard is liable to be blown about by the wind, especially after it has been freshlyploughed or cultivated, as the young plants haveinsufficient foliage to protect the ground from thefull force of the wind. During a gale the sand isoften blown with considerable force against thestems and foliage of the trees to their great injury. Along the Murray Valley the weather is usuallyfairly calm during the summer and autumn months,but during September and October the equinoxialgales often blow with great force and persistence.During these storms, on newly -ploughed and freshly-planted orchards situated on sandy land, the damagedone is sometimes severe the drifting sand barkingthe trees, destroying their foliage, and even coveringthe irrigation channels with sand. To avoid lossesfrom sand- drift in newly -planted orchards it is neces-sary that the soil should be held together by a massof plant growth. This can be accomplished bysowing strips of cereals or legumes in the rows theway it is intended to water. If the trees are planted20 feet apart a 9 feet strip will be sufficient for thefirst season, and a 6 feet strip for the second and thirdyears. In every case the cover crops should besown during the autumn or early winter months, sothat the crop is of some considerable height bySeptember, when the windy weather begins.
24 On newly-planted lands containing a fair supplyof humus, such as on deep mallee soils, where it isnot necessary to plough in green crops for manurefor some years, the cover crops may consist of cereals,such as wheat, oats, or barley. Wheat has provedto be a very satisfactory cover crop for the firstthree years among young trees, if drilled in withmanure in strips from 6 feet to 9 feet wide. Enoughhay can in this way be grown to keep the growershorses for some years, and provided the crop ismanured on a liberal scale, no injury to the landor the trees should result. After the trees are threeor four years old they should have developed sufficientgrowth to shelter the ground from the worst effectsof the wind, and cover crops for shelter will nolonger be required. Trees planted in land having a deficiency of humuswill not make satisfactory growth, and that com-pound must be added to the soil if the orchard is tobe a success. The cheapest way to get humus intothe soil is by ploughing in green crops. The cropsgrown for this purpose are generally legumes, suchas peas, clovers, vetches, which acquire, through theagency of the root-inhabiting bacteria, the necessarynitrogen for their growth out of the air, so thatwhen they are ploughed in both humus and nitrogenare added to the soil. Like cereals, legumes are bestsown or drilled in with a good dressing of phosphates,say, 2 cwts. to the acre in the autumn, so as to bewell established before the cold weather sets in. The best time to plough in is when the crop is inflower, and it should first be rolled down by shortintervals abreast of the plough, so that the ploughis able to turn the crop under. As the clean system of summer cultivation that isnecessary to practice under irrigation burns up thehumus in the soil, it is advisable to plough in greencrops in established orchards at regular intervals.
25 CHAPTER VIII. IRRIGATION. As previously stated trees are usually irrigatedon the furrow system, that is, one or more furrowsare ploughed on each side of the rows, and the wateris allowed to run along them until the orchard hashad sufficient. The check system flooding the landwith an even sheet of water is sometimes practisedon level land of a rather stiff nature but owing to ;the heavy cost of grading where the land is at allhilly or undulating, this method is not practised toany considerable extent. As it is necessary for the success of the orchardthat every tree should have as nearly as possiblethe same amount of water, the watering should beBO managed that the water does not take too longto reach the last trees of the row, nor should it beso rapid as to cause a washing away of the soil atthe beginning of the row. As far as circumstanceswill permit, this end may be attained by the application of the following principles to the varyingconditions of soil and grade. Firstly: Fairly level land of a stiff nature. Thisclass of land, whether watered by flooding or byfurrow, may be irrigated with a large stream ofwater running into the checks or along the furrows,as tho grade (if any) is insufficient to cause a washingaway of soil, and the soil too tenacious to absorbthe water quickly. On the river flat land it is, onthe whole, not quite so essential to economise in the use of water as it is on the highlands, as the under-
26drainage is usually good ; but heavy watering mayresult in water, -logging the land for a time to theinjury of the trees. Secondly: Short steep rows on sandy land. These should be watered with a small stream runningalong the furrows for a comparatively long time.Watering with a large stream down steep slopessoon washes the top soil away, causing deep guttersto form, while the washed-out soil silts up the fur-rows further down the slope, so that the water spreadsthere, and very little reaches the end of the rows.A small stream will not cause this trouble, but asby this means the quantity of water going into thesoil is not very great at any time the time of water- ;ing must be extended to allow for this. Thirdly: Rows of moderate length and gradeon sandy slopes. Eows of 5 chains in length, with agrade of about 9 inches to the chain, give very satis-factory results in irrigating. These are best wateredwith a moderate to large stream along the furrows,and will give little or no trouble through silting.The size of the stream to use depends not only onthe grade but also on the nature of the land. Thesandier the land is, the more will it be absorbent ofmoisture, and the longer will the water take to getto the end of the rows. Therefore to get as nearlyas possible an even distribution of water over thewhole orchard it is necessary, other things beingequal, to make it a rule in irrigating to follow theprinciple of the sandier the land the larger the stream. Fourthly: Rows of moderate length with butlittle grade on sandy land. These should bewatered with a large stream running along thefurrows for a comparatively short time, for towater such rows with a moderate to small streamwould cause the top trees of the row to receive toomuch water before the last ones have had sufficient.
27 As stated in previous chapters, nothing is so detrimental to the welfare of the orchard as to wateralong an almost level grade on sandy land for the ;great quantity of water it is necessary to use beforethe end of the rows are watered may cause seepageto appear on the lower portion of the holding shouldthe under -drainage of the land not be perfect. Butseepage may also be brought about, even on landthat has been well laid out, both as regards chan-nelling and planting, if the watering is careless orexcessive. One of the quickest ways to ruin apiece of land is to water along a gentle grade witha small stream, or along a fairly steep grade with a-large stream. In both instances the upper portionof the rows gets too much water and the lower portiontoo little, with the likelihood of seepage appearingon the lower part of the holding at some time. The chief work in connection with the irrigationof the orchard is to see that the furrows are keptrunning. Weeds and leaves will occasionally blockthe outlet pipes, and these must be removed. Fur-rows that are silting up must be cleared, and thosethat have burst must be repaired. Where the landhas been well laid out for watering not much workis experienced in its irrigation ; still it is necessaryfor a man to be in attendance for the greater portion,of the time to see that all goes well. AMOUNT OF WATER TO USE. The art of irrigation may be said to consist ofsecuring the maximum of crop from the minimumof water. The advantages of not using more waterthan is absolutely necessary is apparent for threereasons : firstly, that irrigation, which is at best amussy occupation, should not be unduly prolonged,as this results in a waste of time and labor : secondly ,that the economical use of water lessens the dangerfrom seepage ; and thirdly, that excessive wateringleaches out the most expensive plant foods, such asnitrates, contained in the soil, and carries them deep>
28down into the sub-soil out of the reach of the rootsof the plants. Provided that* the land is k3pt well cultivated,newly-planted trees do not require more than from15 inches to 20 inches of irrigation water the firstseason. When once established and before theycome into bearing, trees planted on sandy land canbe kept in vigorous health on 15 inches and under ofirrigation water per annum. One of the greatestmistakes often made by newcomers on irrigationareas is in watering too heavily. On most of theirrigation settlements the regulations formulated bythe governing authorities permit the individualirrigationist to use up to 24 inches of water per acre ;but these regulations are not always enforced, withthe result that inexperienced irrigationists often putfar more water on to their land than is good for it.Seepage, the greatest foe the irrigationist has to fear,is more often brought about by excessive or carelesswatering than by any other means. Experience hasshown that 24 acre inches per annum is amply suf-ficient for vines and trees in full bearing, and thatwith good cultivation it is possible to obtain theheaviest crops with considerably less water than this. SOME EXPERIMENTS IN IRRIGATION. To give practical illustrations of the results thatmay be obtained by an economical use of watercombined with thorough cultivation the writer hopes ,that he may be pardoned by here introducing theresults of a few experiments made at his plantation,which is situated on the uplands of Berri. For irrigation purposes, the citrus plantation wasdivided into three different sections, each sectionreceiving different amounts of water. Meter read- .ings were not kept until the trees were in their thirdyear. Naming the sections A, B, and 0, the irriga-tion records are as follows :
29 SECTION A (Five Acres). Seven Tears Old, 1919.Season. Acre inches Eainfall 1st Total Water
30 Although during these five years Section B re-ceived 98 acre inches of irrigation water as against76.5 acre inches received by Section A, yet the growthand general health of the trees on both sections,which are situated on similar soil, was, as far as allappearances went, identical. However, during the1917-18 season, as shown by the occasional wiltingof some of the trees, it was evident that Section A,with 13 inches of irrigation water, had received theminimum amount, lower than which it was not safeto go if the crop was not to be lost. Nevertheless,on Section C, during the 1917-18 season, the appli-cation of 14 inches of irrigation water proved suf-ficient to mature an average crop of four cases offruit per tree from a section of mandarins situatedon land of a similar nature to Sections A and B. PERIODS OF WATERING. In normal seasons citrus trees are watered atintervals from August or September to the followingApril, in five or six irrigations, on an average ofabout six weeks apart from each other. If theSpring is wet or cool, the first two irrigations neednot be heavy, but gaod waterings should be givenduring the late Spring and Summer months, i.e.,from November to March. On no account shouldthe trees be allowed to get dry at the roots duringthis period, or the crop will be lost. For the fillingout of the fruit, unless there have been heavy Autumnrains, an April irrigation is necessary.
31 CHAPTER IX. CULTIVATION. So closely connected with irrigation as to be prac-tically a part of it is the subject of cultivation. Theirrigation of a piece of land is of little use unless it isfollowed by cultivation, as the water poured into thesoil soon evaporates unless the surface of the groundis kept well stirred. Cultivation destroys the smallcapillary tubes along which the moisture passesthrough the soil into the atmosphere, and by thusforming a blanket of loose earth on top, throughwhich evaporation can only imperfectly take plaQe,.the lower layers of the soil are kept moist. Another result of cultivation is that by checkingevaporation the formation of alkalies on the surfaceof the ground is prevented. In arid regions, such as the greater portion of theMurray Valley consists of, the rainfall has neverbeen sufficient to leach much of the natural saltsout of the land and to carry them away in the riverwater. When this land is irrigated some of thesalts are dissolved by the water. Capillary actiondraws the salt-impregnated water to. the surface ofthe ground, where the water is evaporated and thesalts left as a residue.As some of these salts arehighly detrimental to plant life, being especiallyinjurious when concentrated on or near the surfaceof the ground to the crown and surface roots offruit trees, it is necessary, were it only for thisreason alone, that the work of cultivation in theorchard should be of a thorough nature.
32 During the early part of the season, while theweather is still cool, the cultivation of the whole ofthe orchard is not quite so essential as it is duringthe sumnur nunths. If cover crops intended forhay, such as wheat or oats, are grown in betweenthe rows of young trees, these should occupy stripsof not more than 6 feet wide, so that a two-horsecultivator can be driven along each side of the rowsof trees. After such cover crops are mown, whichwill be either in October or November, the wholoorchard should be cultivated or disc-harrowed, andkept well-workod and free from weeds for the restof the season. Where the land cannot be stirred by horse-culti-vation, such asnear the stems of the trees,the land must ba kept loose and the weeds destroyedwith the hoe. Young trees should receive specialcultivation close to the tree, as the roots are not farfrom the stem, and the forked hoe, which does notcut the roots, if by accident it is inserted too deeplyinto the soil, is a very useful implement for thiswork. To ensure satisfactory growth in a youngorchard too much care cannot be exercised in thiswork of close cultivation, as every weed is a pumpdrawing the moisture into the air that the youngtree requires for its needs. One of the greatest mistakes often nude by new-comers on irrigation settlements is the lack of insufficient cultivation. How often are not newly -planted orchards met with with but a 2 feet to 3feet strip of cultivated land along each side of therows of trees, while the rest of the land is givenover to the production of a crop of luxuriant weeds,which rapidly pump the moisture out of the land,and by creating a dry belt alongside the cultivatedone, rob the latter of most of its moisture. Undersuch circumstances it is impossible for the trees tomake satisfactory growth, and the development ofthe orchard is retarded. The cultivation of a piece of land, by checking:evaporation from out of the ground, causes most of
33the moisture to remain in the soil for the use of theplants occupying the land. Therefore the morethorough and more often the cultivation of theorchard takes place the less will ba the evaporation,and consequently the smaller will be the quantityof water required to maintain the plants in goodcondition. The golden rule for the irrigationist toadopt is to apply the minimum of irrigation withth$ maximum of cultivation consistent with thesatisfactory growth of his plants. To follow theopposite principle to make up for lack of cultiva-tion with excessive irrigation -is to court disaster,for such a policy, if persisted in, causes either theformation of surface alkalies or the water-loggingof the sub-soil, or both, and ultimately results in thedeath of the plants and in the ruin of the land. A cultivation of the orchard should follow everyirrigation after the ground has been allowed to drya little, so as not to puddle the soil, and also afterevery rain of any consequence. Where the groundis naturally hard or turns up in lumps, an additionalcultivation in between each irrigation is desirable.During the late autumn and winter months, if nocover crops have been planted, weeds may be per-mitted to come up, but should be ploughed in greenin the early spring. Cover crops intended for greenmanure should be rolled down and ploughed in whenin flower, and the whole plantation should be ploughedup every season during the late winter or early springmonths, after which no more weeds should be per-mitted to grow for the rest of the season.
34 CHAPTER X. PRUNING. " *- n As a whole no classof fruit trees require lesspruning than citrus trees. At the time of planting the young trees should be cut down to about 18inches to 2 foot. When growth commences youngshoots will spring out all along the stem. All shootsbelow a foot from the ground should be rubbed off,thus allowing a clean stem of at least a foot where thetrees have been cut back to 18 inches. Where thetrees have been left 2 feet high a clean stem of 18inches should be left. Some years ago it was thecustom to grow high -headed trees having a baretrunk of 4 feet or over. Experience having proved that high -headed treesare more liable to suffer from strong winds, moreliable tohave their stems injured from sun burn, andthat the fruit was not so cheaply to gather as fromlow-headed trees, some citrus growers went to theother extreme, and headed their trees but a fewinches above the bud. This made for a low, bushytree, with branches very close to the ground, whichbrought a portion of the fruit into contact with theearth, and with the limbs so low as to be in the wayof horse cultivation. It was therefore found thata clean stem of about 18 inches in height gave thebest results. Citrus trees usually make from two to four growthsduring the season. The growth of young trees isoften so rapid that it cannot support) itself and bends ,down until it touches the ground. It is not advisableto have the branches as low as this, as on frosty nights
35the cold is and the fruit greatest nearest the ground,is liable to whenever the be frost bitten. Therefore,branches bend down too low they should be cut backto an upward bud at the place where the downwardarc commences. The main branches of a citrus treeshould have an upward tendency. The naturaldrooping habit of a citrus tree so trained will soonassert itself again through the formation of sidebranches, and through the weight of the fruit. Citrus trees that have become too dense in thehead should be thinned out somewhat, so as to let ina little light and air, as darkness is conducive to thegrowth of insect pests. All dead wood should alsobe removed. All water-shoots growing out of the old wood arebest removed, as these often grow with excessivevig >r, and by taking up a great portion of the sap ofthe tree rob the other branches of nourishment, thusmaking for a lob-sided development. The best time to prune citrus trees is during springand early summer, as if left too late in the seasongrowth will often have taken place on shoots orbranches that would have been pruned away at thespring pruning, thus resulting in waste of energy.
CHAPTER XI. MANURING. Of all the operations connected with the growing ofcitrus fruits tho subject of manuring is one of the mostimportant. However rich the soils may naturallybe, through continual cropping they will, sooner orlater, become impoverished, unless sufficient fertiliseris applied to the ground to replace the plant foodremoved. The elements which enter into thecomposition of plants are carbon, oxygen, nitrogen,hydrogen, potassium, calcium, magnesium, phos-phorous, sulphur, and iron. Of these, all exceptnitrogen, potash, phosphorous, and sometimes lime,are usually present in sufficient quantities for theneeds of the trees. Young citrus trees require a liberal supply ofnitrogen if they are to make vigorous wood growth.When the trees come into bearing very large amountsof nitrogen are no longer necessary, as they impair thefruitfulness of the trees, wood formation taking placeat the expense of fruit. Citrus trees of all agesshould always be supplied with a liberal supply ofphosphoric acid (phosphates) or the health of the treewill suffer, and the fruit will not develop normally.For the formation of citrus fruits a plentiful supplyof potash is essential. Harold Hume, of the Univer-sity of Florida, the American citrus expert, says ofpotash manuring in respect to citrus trees : "Iflarge amounts of potash are taken up by the treesit will be found that the rind of the fruit will be muchthinner than otherwise and the amount of rag willbe greatly lessened. A plentiful supply of potashin the fruit has an excellent influence on its keeping
37quality. If too little be present the fruit will be softand is likely to break down shortly after, removalfrom the trees. To increase the keeping and carryingquality of citrus fruits a large amount of potash and asmall amount, of nitrogen should be used." STABLE MANURE. Stable Manure is one of the best of fertilizers to to the soil, having a fairly high nitrate con-tent as well as being valuable for adding humus tothe land. Four one-horse drays will hold about oneton of this matter in a dry state, which, if spreadover an acre of land, will enrich the soil with humusto about the same extent as an average cover crop,although its nitrogen -enriching properties are con-siderably less. A ton of stable manure to the acrewould be a very light dressing to give, so light, infact, that it would be a somewhat difficult matterto spread it. over the land thinly enough to go round.A dressing of four or five tons to the acre appliedevery third year would give satisfactory results,and keep up the humus content of the soil. The fertilising elements in a ton of rotted stablemanure have been variously computed to consist offrom 6 to 7 Ibs. phosphoric acid, 6 to 12 Ibs. of potash,and from 8 to 15 Ibs. of nitrogen. This would beequal to about 21 Ibs. of superphosphates, 12 to 24 Ibs.of sulphate of potash, and from 75 Ibs. to 120 Ibs. ofblood manure. This is from manures in a partlyrotted state, hence containing considerable quantitiesof water, but the quantities of these ingredients froma perfectly dry sample would probably exceed thisamount to some extent. CHEMICAL FERTILIZERS. As in many instances it is not possible to obtainsufficient quantities of organic matter to bring onto the land to make up for all the nourishment from the soil by continuous cropping,
38chemical have to be used to make up the fertilizersdeficiency. As Australian soils generally appear tobe somewhat weak in phosphoric acid, phosphatesare usually the first kind of manures used to main-tain the crop returns from the land. Commercialvarieties of phosphates are of two kinds, the organicclasses, such as bone dust and bone superphosphate,and the inorganic forms, made from various kinds ofphosphatic rock. Of these bone dust is the slowestin its action, lasting about two seasons in the soilbefore being entirely dissolved. By not being sowater soluble as other kinds of phosphates, themanurial properties of bone dust are not so readilyleached out of the soil by heavy rains or irrigation,and, therefore, although slower, last longer in thesoil for the roots of plants to feed on. The mineralsuperphosphates are usually water soluble to a greatextent, hence their action on plant growth is rapid,and for this reason their effect is not lasting, there-fore must be applied annually to keep up growthand crop returns. Potash as a fertilizer is also needed on most soilsthat are being continuously cropped. As has beenpreviously mentioned, potash is usually containedin considerable quantities on many classes of claylands, but it often needs applications of gypsum tomake it available for plant growth. Lime may also be applied on many soils with greatbenefit, especially on heavy clay lands, which arerendered looser and generally more productive bythe action of the lime in making more availablemany of the plant foods contained in the soil. DEPLETION OF SOIL BY CROPPING. The depletion of a soil by cropping depends, ofcourse, upon the nature and extent of the crop.Accoring to Hume, in his work on Citrus Fruits,800 Ibs. of oranges will remove from the soil J Ib.phosphoric acid, 2 Ibs. potash, and 1 Ib. nitrogen.A crop of 400 Australian cases, weighing about
3920,000 Ibs., would at this rate deplete the soil to theextent of 12 Ibs. phosphoric acid, 50 Ibs. potash,and 25 Ibs. nitrogen. In addition to this, allowancemust be made for a quantity of plant food necessaryto make good leaf, branch, and root growth, and forthe amount of these ingredients leached out of thesoil by rain or irrigation. Assuming the totalamount of plant food removed from the soil bythese agencies to be three times that taken out bythe fruit alone (Humes estimate) then the quantityof these substances lost to the land would be :37 Ibs. phosphoric acid, 150 Ibs. potash, and 75 Ibs.nitrogen. Allowing for an 18 percentage of phos-phoric acid, a 50 percentage of potash, and a 20 per-centage of nitrogen, this is equivalent to 2 cwt. ofsuperphosphate, almost 3 cwt. of sulphate of potash,and 4 cwt. of sulphate of ammonia, or to a total ofabout 9 cwt. of chemical fertilizers. Supposing such a crop of 400 cases of fruit wereremoved from one acre of ground, 9 cwt. of chemicalmanures would, therefore, be required to make goodthe deficiency in the soil caused by the productionof this quantity of fruit. METHODS OF APPLICATION. Different classes of fertilizers may be applied atvarious times of the year. Such slow -actingmanures as vegetable mould or bone dust, whichcontain ingredients not easily leached out of the soilby rain or irrigation, may be applied during winteror early spring, as but little plant food would be lostbefore the root activity commences. On the otherhand, fertilizers containing highly soluble ingredients,such as most mineral superphosphates and thevarious classes of nitrates, are best applied duringearly spring or summer, when the roots of plantsare active^ Generally speaking, phosphates shouldnot be put into the ground later than October if thecurrent crop is to receive their full benefit, butnitrates may often be advantageously applied, as in
40the case of citrus, during summer as well as spring-time. Manures may be put into the ground either bybeing drilled in, broadcasted and ploughed in, or bybeing scattered along the bottom of plough furrowsand ploughed in. Drilling in manures with thewheat seed drill cannot ba recommended, unless theland is ploughed deeply afterwards, as the drill onlypenetrates the soil for a few inches, and the manureis placed thereby too near the surface of the soil forthe roots to obtain, especially where the furrowsystem of irrigation is practised and the water doesnot leach the manure down to the roots. Broadcasting and Ploughing in the fertilizer istheoretically the best way to apply manures, asevery portion of the orchard is then evenly supplied.In practice, however, unless the land is cleanly anddeeply ploughed, all the fertilizer will not be turnedinto the bottom of the furrow, and, moreover, wherethe- furrow system of watering is used, a great por-tion of the manure will not receive sufficient moistureto carry it down to the roots of the plants because itis not evenly distributed. Manuring in Furrows, despite its disadvantages,is the best to apply fertilizer where the furrow waysystem of irrigation is used. One or more deepfurrows should be ploughed along the rows of treesor vines, not closer than four feet to the stems ofbearing trees, and the manure scattered in thebottom of the furrows -the furrows then ploughed inand the new furrow thus formed used to water theplantation at the next irrigation. By this methodthe fertilizer is put deeply into the soil, therebytending to keep the roots down in their search forplant food. By being in close proximity to theirrigation water the fertilizer is easily dissolved forthe use of the roots of the plants; but for this reasonan extra heavy irrigation should not follow theapplication of manures, as some of the propertiesmay be washed too deeply into the sub-soil for theplants to reach.
41 CHAPTER XII. HARVESTING AND PACKING. Along the Murray Valley, in normal years, man-darins ripen in June and July, the Washington Navelduring June, July, and August, and the ValenciaLate during October and November, but the last-mentioned variety will often hang on the trees untilthe end of the year. Oranges should not be picked until they are wellcolored, as if gathered and placed upon the marketwhile the skin is still partly green the acidity of thefruit has a detrimental effect on both the demandand selling value. In picking oranges secateurs are generally used.The fruit is first severed from the tree with a stemof twig about an inch in length adhering to it. Thisstem is then carefully removed by cutting it off asclosely to the skin as possible without injuring therind, and the orange is then placed in the pickingbag or receptacle used for holding the fruit. The use of the double cut has been found to resultin speedier and neater harvesting operations thanif it is attempted to sever the fruit from the tree bycutting quite close to the rind by means of a singlecut in among the branches and leaves of the tree.The object of cutting the stem away quite close tothe fruit is because if it is left projecting it is apt toinjure the other oranges while standing in the pickingtins or boxes by piercing or otherwise injuring therind. Oranges are either firstly picked into picking bags,or placed into picking tins or picking boxes direct.
42In handling, the greatest care should be exercisedthat the rind is not bruised or cut, as fruit so dam-aged quickly developes decay. After being har-vested, oranges should be allowed to sweat for afew days in the picking boxes before they are sent tothe packing house, as the skin in shrinking becomessomewhat tougher and is in consequence not so easilyinjured whilst the fruit is being packed. In packing, oranges are first graded, either bymechanical graders or by hand, and are then packedaccording to the diagonal system of packing intostandard bushel cases. The number of Washington Navel oranges thatrfare packed to the case varies from about 53 for verylarge fruit to about 200 for small fruit the sizes atpresent most favored by sellers at Melbourne (thechief market for navel oranges in Australia) beingthose of medium size, i.e., fruit going from about83 to 154 per case. Mandarins are usually packedon the diagonal system, and vary from about 200to 300 per case. After having been stencilled,packed, and nailed down, the number of fruits eachcase contains is branded on the outside of the case. At present, the packing and marketing of citrusfruits is carriedon by both individual growers andby associations of growers in the form of co-operativesocieties. Although it may pay individual growers harvestinglarge quantities of fruit such as 1,000 cases or overto erect private packing houses with all up-to-dateappliances, such is not the case with smaller growerswho have but a comparatively small quantity offruit to handle. In such instances growers haveeither to hand-grade, pack, find markets, and consigntheir fruit themselves, or to send it to a packingassociation to do this work for them. As the Quantity of citrus fruits produced yearlyincreases, due to the large plantings made in recentyears, thereby making increased marketing facilities
43essential,both in the Commonwealth and overseas,it seems highly probable that individual growers,acting independently of each other, will not be ableto cope satisfactorily with the situation in the future,and that the handling of the fruit through large co-operative organisations will become necessary.
44 CHAPTER XIII. DISEASES AND INSECT PESTS. MAL-DI-GOMA. Oneof the worst diseases of citrus trees in Americais mal-di-goma, or foot rot. It is also prevalent inAustralia, although not to so great an extent. Footrot attacks citrus trees at the crown roots, extendinga foot or so above the ground and downward amongthe roots. The presence of the disease is first noticedby the discharge of gum at the diseased spot. Lateron the bark rots away, and the tree eventually dies.The disease seems to be caused either by water standingaround the roots, the crown roots becoming injuredthrough Careless cultivation or otherwise, or too deepplanting. As these matters rest greatly in the handsof the grower, the careful orchardist will see that histrees do not needlessly suffer from these causes.Where the land has to be flooded to water the treesthe trees should be budded on the Seville stock, asexperience has amply proved that both sweet orangeand lemon stock are liable to suffer from foot rot ifplanted in wet situations. Affected trees should have the earth removed fromaround the main roots, the decayed portions of thebark cut clean away, and after the ground has beenwell aerated, fresh soil obtained from outside of thecitrus plantation should again be placed around theroots. MOTTLED LEAF. A A disease that has been doing considerable damageto some of the citrus plantations of the Hurray Valleyduring recent years is that known as "mottled leaf."
45This disease is due to the partial absence of the greencoloring matter, or chlorophyll, in the leaves of thetree, and gives the leaves the appearance of beingvariegated yellow and green. As the disease progresses, the yellowing of theleaves increases, until these turn practically all yellow,the branches die back, and little, if any, fruit is set. In his valuable book on "Citrus Fruits," ProfessorJ. B. Ooit, of the California University, mentions thatthis disease was probably the most serious problem thatCalif ornian citrus growers had to face. At the presenttime the cause of this disease is but imperfectlyknown, but as many Californian experimenters arenow investigating this citrus malady it is to be hopedthat a satisfactory solution of this problem will aoonbe found. The writer has seen trees badly affected on landshowing signs of over-irrigation, on land showingtraces of alkali trouble, and to a lesser extent in situa-tions where the conditions for citrus culture wereapparently ideal. That mottled leaf may in some instances be over-come by the application of somewhat heavy dress-ings of organic nitrogenous manures, the writer hasproved from his own experience. The trees on aportion of his citrus plantation growing in a deep,red soil, which was but poorly supplied with humus,developed mottled leaf to a considerable extent, -sothat their growth became very slow, and no fruitwas set. A dressing of stable manure equal to about5 cwt. per tree was spread over the land and ploughedin early in the Spring. Within a few months thetrees were showing signs of recovery, and after a yearthe mottled leaf had practically disappeared the ;trees were making vigorous, healthy growth, andhave remained in good condition ever since. Growing among the other perfectly healthy trees odd trees here and thereof the writers plantation,developed mottled leaf, although the conditions
46favorable to their growth were to all appearancesperfect. These trees were treated with organicnitrogenous manures applied in liquid form, fromone to three applications being given, and within ayear from the first application the mottled leaf haddisappeared and the trees were making strong,healthy growth. ORANGE SCALE. Red Scale is a small circular insect of a reddishbrown color,which increases very rapidly undercircumstances favoring its growth, which are moistand muggy atmospheric conditions. The only effec-tive way of getting rid of it is by fumigating thetrees with hydrocyanic acid gas, which is generatedby treating potassium cyanide with a diluted solu-tion of sulphuric acid. Fumigation is done in thenight time, the gas being liberated under a tent,which covers the tree. For 100 to 150 cubic feet oftent space the amount of ingredients generally usedare 1 oz. potassium cyanide, 1 oz. sulphuric acid, and3 ozs. of water. The red scale, which the most harmful of all is up to the presentinsect pests to the orange tree, hastime not made its appearance among the orangegroves of the South Australian portion of the UpperMurray Valley. Brown Scale. This variety of the genus of Leca-nium, or unarmored scales, is fairly well known tothe citrus growers of the Murray Valley. The full-grown insect is about one-eighth of an inch long,broadly oval, convex upon the disc, surrounded bya thin flat margin, and of a brownish color. Thescale thrives upon the bark and leaves of the branchesof the tree by sucking out the sap, and is generallyfound in the greatest numbers in situations notdirectly exposed to the sun.
SPRAYING. The usual methods used for combating this scaleare by means of sprays made of oils of various kindsand of resin compounds. Fed Oil. Various brands of red oil" mixture areupon the market. The usual methods of mixing areto take equal quantities of rainwater and red oil,place the oil in a bucket or spray pump, add thewater slowly, stirring or churning vigorously thewhile. When, the oil and water have thoroughlyemulsified, add twenty times as much water as thereis emulsion .that is, forty times the amount of oilused and mix up well in the barrel of the sprayingoutfit. This mixture may be considered as fullstrength, and a stronger solution than this is notadvisable. The chief thing to see to at mixing isthat the oil and water emulsify thoroughly, whichwill not be the case if the water is at all hard, andshould it be in this consition it should first be softenedby dissolving a handful of washing soda in it beforemixing it with the oil. The usual time for using red oil spray is in thesummer months, generally during the months ofJanuary and February, and to guard against sun-scald of the leaves and fruit is best applied duringa cool spell during these months. Should the weatherbe warm to hot when the spraying is being done, asolution of one gallon of oil to 50 gallons of waterwill be found strong enough to kill the scale. Kerosene Emulsion is preferred by some growersfor spraying purposes. This is made up in the pro-portion of 2 gallons of kerosene, Ib. soap, 1 gallonwater. The soap is dissolved by boiling in the gallonof water. The water is taken off the fire, and thekerosene added slowly, the mixture being churnedwith a spray pump for ten minutes or so, until astable emulsion is formed. Another gallon of warmwater is then added, bringing the solution up t>4 gallons.
48 Spraying is usually done in the summer monthsin between the growths, that is, when one growthhas finished and before the next starts. For spray-ing at such times each gallon of the emulsion isdiluted with not less than ten gallons of water ; butfor trees that are in active growth fifteen gallons ofwater to one of the emulsion will be strong enoughfor the young foliage to withstand. For badlyaffected trees two sprayings about a fortnight apartmay be necessary to eradicate the scale. Resin Wash. Owing to the scalding effect uponthe leaves and fruit that sometimes follow the useof the various oil sprays, some growers prefer spray-ing their citrus trees with a resin wash made up inthe proportion of 1 Ib. resin, 1 Ib. washing soda,J Ib. soap, to 5 gallons of water. This is applied ina similar manner as the oil sprays, and usually butlittle damage to the foliage of the trees is done. NoU. -No spraying of citrus trees should beattempted ifthe trees are in want of moisture, aswhen in this condition the leaves of the trees haveoften not sufficient vitality to withstand the suf-focating effects of the spray, and so fall off ; whereasit the spraying takes place when the leaves are fullof moisture, such as after an irrigation, and otherconditions are favorable, ill-effects seldom follow.
49 CHAPTEB XIV.COST OF BRINGING A CITRUS PLANTATION INTO BEARING ON STATE IRRIGATION AREAS OF SOUTH AUSTRALIA. To estimate the amount of capital required tobring a citrus plantation into bearing is a some-what difficult subject, as the price of material and oflabor is a fluctuating quantity, and, further, owingto the fact that the expenses per acre will vary withevery holding, as no two pieces of land will cost thesame to clear, grub, grade, and to maintain in goodcondition. However, a rough average, both on thecapital outlay and upon the income per acre, can bestruck, and the estimates here drawn up have beenchiefly compiled from Berri data. As the price of labor, material, water rates, etc.,have greatly risen since the beginning of the war,and as this increase in prices shows no immediatelikelihood of falling, the estimates here drawn upshow an advance on those quoted in my book, Fruit-growing under Irrigation, which were compiledaccording to normal pre-war costs. As this chapter is chiefly written for new settler*on the State irrigation areas along the MurrayValley in South Australia, it has been taken forgranted that the assistance of the Irrigation Depart-ment in fencing, grading, grubbing, and channellinghas been availed of. Where this has not been done,the initial outlay will probably be increased by 10per acre.
50 ORANGES (WASHINGTON NAVELS). CAPITAL OUTLAY ON ONE Actss. Initial Outlay. s. d.15 per cent, deposit Irrigation Depart - ment for channelling, grubbing, at 12 per acre ., 1 16Ploughing ..100 orange trees .. , .," ;,. .*..*., 100 .. .^ .. Vr 10Pegging out and planting 1 10 v Total initial outlay ":; . . 14 6 UPKEEP.Cultivation for five years .. .. *.,*; 25Water rates and rent, five years , 717 6 s-Cl . 500 . .Pruning and spraying, five years .. "...Net expenses for sixth year, after de- ducting net income .. ;....". ">-* 300 Total upkeep 40 17 6 .".. ?^ .. HARVESTING PLANT. s. d.Picking or sweat boxes *f> .. .. 200Proportionate expenditure on storing or curing shed riri^? ,.;. ve<> *. 800 * Total ] ^ , ti >.; .. 10 s. d.Interest on initial outlay and upkeep for six years .. .. .. .. .. 10 10Owing Irrigation Department after five years 10 Total capital outlay . . . . 85 13 6
51 The initial outlay for planting an acre of orangesisgreater than that of any other class of fruit, owingchiefly to the greater cost of the trees themselves.In planting, also, greater care than is necessary withother trees has to be taken, and if the season is drya special irrigation will be needed at planting time. On calculating the annual expenses of cultivationand irrigation at 5 per acre a low estimate hasbeen taken. Aglance at the young orange planta-tions at Berri at once reveals the blocks that havereceived the best cultivation. So readily do orangetrees respond to good cultivation that a first classlooked after orange grove will come into profitablebearing at least? a year before a block that hasreceived but average attention. Orange trees ought to produce some fruit in theirfifth and sixth years. Allowing for half a case pertree at six years, at the price of 5/ per case net.This would still mean a net expense of 3 per acre,after deducting all working expenses for the year. As well as other fruit, oranges require a harvestingplant. In addition to picking cases or sweat boxes,a storeroom or curing shed will have to be erected, asoranges, after being picked, are generally storedor "cured" on shelves or shallow boxes for a fewdays to a week to allow the skin to shrink and becomeleathery before being sent on a long journey. Through orange trees taking so long to come intobearing, the loss of interest on the capital investedis considerable, and after six years amounts to 10 10 /, thereby adding that sum to the cost per acre. A total capital outlay of 85 per acre for six years *appears, no doubt, a large sum ; but on carefulconsideration I cannot see how it can be reduced.In the above estimate no loss is allowed for treeadying in their first year before they are established,neither for special irrigations at planting or othertimes, or for carting water to young trees during dryspells in between irrigations. So, if anything, thetotal expenditure could easily be increased.
52PROBABLE INCOME FROM AN ACRE OP ORANGES. Oranges planted in good, deep usually com- soilmence to bear in their fourth year. The crop, how-ever, will be inconsiderable and the fifth years ;crop will also be small. At six years half a case tothe tree may be expected, while at seven years thetrees should be bearing a case or more to the tree. R Regarding prices, it is obvious that, owing to thedecreased purchasing power of money, due to theincreased cost of living that has taken place in recentyears, the minimum price at which oranges will payto grow is considerably higher now than it was afew years ago. If the minimum payable net pricewas 4/ per case two or three years ago, then it isat least 5/ per case to-day (1919), and should thepurchasing power of money continue to fall, thenthe payable minimum price must show a correspond-ing rise. Therefore, under the economic conditionsexisting in these changing times, the following cal-culations can only represent some general approachto accuracy for probably the next few seasons. Allowing for net prices to the grower of 5/ and 6/per case, and calculating 100 trees to the acre, thismakes an income of 25 and 30 per acre respectivelyat one case per tree. In my estimates for full bearingtrees the annual expanses have been estimated at 28 5/ on a crop of two cases per tree. But on acrop of one case par tree the expenses of manuring(4) and of harvesting (8) will only be one half ofthat of full grown trees, so a reduction of 6 peracre must bo allowed for this, thus reducing theannual expenses to 22 5/. A crop of .one case pertree, at 5/ net per case, would, therefore, just paya little over working expenses if no allowance fordepreciation were made. Coming to the subject of depreciation, no deduc-tions have been allowed for the firsfc 10 years of theplantations existence, as the irrigation channels
or pipes should be in good repair, and if the site stillof the plantation has been well chosen, as regardssoil and position, seepage troubles should not havemade an appearance in so short a time. I have estimated the total life of the trees at30 years. The first six years as a period of infancy, Ithe time from the seventh to tenth years as the ageof coming into bearing and paying working expensesand somewhat over, and the period from the tenthto thirtieth years as the age when in full bearing.During these last 20 years an annual allowance of 2 per acre has been debited for depreciation onharvesting plant, channels, and for provision fordrainage, as well as an additional depreciation of5 per cent, per annum on the capital outlay of 85. In the estimate I have calculated the averagecrop at 200 cases per acre, commencing in the tenthyear of the orchards existence, and continuing atthat rate for the following 20 years :PROBABLE INCOME FEOM AN ACRE OF WASHINGTON NAVELS s. d.200 cases at 6/ per case net . . .. 60200 cases at 5/ per case net . . . . 50 ANNUAL EXPENSES. s. d.Cultivation, ploughing, irrigation 700 500 . .Pruning and spray, ng . . -. . . .Water rates and rent .. - 2 5 400 . ....Manures .. .. .. .. ..Harvesting and curing expenses .. . ^ 8Expenses of management and superin- tendence . 200 Total .. . 28 5
54 DEPRECIATION. s. d.On harvesting plant, channels, provision for drainage .. .. .. V-- 200On orangery on 5 per cent, of capital outlay . . . ... . ... . . 450 Total depreciation . . .;/. Total annual expenses - . . ; s. d.Net profit per acre, at 6/ net per case . . 25 10Net profit per acre, at 5/ net per case . . 15 10 According to the above figures oranges will payto grow if 200 cases of saleable fruit, averaging 5/per case net, or over, to the grower, are harvestedper acre. At less than this price, however, orangescease to be profitable as an investment, as the sameamount of capital would probably show a higherrate of interest if invested in other industries.
55 PRESS COMMENTS "From the author (Mr. F. R. Arndt) a copy of Fruitgrowingunder Irrigation has been received. The work is devotedespecially to the conditions in the Murray Valley, and is anexhautive treatise on a subject of great importance at the timethe use of Australian rivers is being considered. . .The.man who intends to enter the fruitgrowing industry will findvaluable information in the chapter devoted to the cost ofstarting an orchard and the time that must elapse before anyreturn can be obtained." Daily Herald, Adelaide, 24th December,1918. "From Mr. F. R. Arndt, of Berri, has come to hand copies ofhis exceedingly interesting and informative book on Fruitgrowingunder Irrigation. The publication contains about 120 pages offacts and comments, which every irrigation fruitgrower shouldbe acquainted with." South Australian Register, Adelaide,24th December, 1918. "For the large and growing number of settlers in our irrigationareas who, in becoming irrigationists, are adopting a mode oflifenew to them this book will be found of great value, and thereare few among the ranks of experienced irrigationists who maynot derive some benefit from its perusal." Murray Pioneer,Renmark, 3rd January, 1919. "I have carefully read Mr. Arndts book on Fruitgrowing underIrrigation. ... It is, to my way of thinking, the best con-nected study on the subject published in Australia, on an Aus-tralian basis. The explanations in relation to all field operationsare simple and to the point, and most practical in character. My personal opinion is that a copy of this book should bein the hands of every new settler or intending settler who proposesentering upon fruitgrowing on the irrigation areas of the Murray-Valley." GEO. QUINN, Horticultural Instructor to the S.A.Government, in the Journal of the Department of Agriculture ofSouth Australia, April, 1919. University of California, College of Agriculture, Berkeley, 18th February, 1919. Dear Mr. Arndt, I have read with deep interest your book,Fruitgrowing under Irrigation. Your statements are very clearand straightforward, and the information conveyed must bevery helpful to anyone undertaking fruitgrowing under yourconditions. I congratulate you on a good piece of work. (PROFESSOR) E. J. WICKSON. University of California, Agricultural Experiment Station, Berkeley, 24th July, 1919. Dear Mr. Arndt, I have just returned to my office from an18 months war emergency job . . (and) find on my desk .the book entitled Fruitgrowing under Irrigation I findit intensely interesting. J. ELIOT Corr, Professor of Citri culture.
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