Irrigation farming: a handbook for the practical application of water in the production of crops
^~ •fc« <z^ 85 •■M «-^ -i 4^ <>H o -^ a,'-* c 3 0; u «^ ^ <H o ^'^ (N P< 46 C4 93 131 258 3&4 527 750 712 1,006 926 1,310 1,468 2.076 2,464 3,617 4,045 5,704 8,303 11,744 14,504 20,516 coP^ 79 163 450 923 1,240 1.613 2.554 4.407 7,047 14,466 25,277 Some Simple Rules. — A miner's inch of water is equal to nine gallons a minute. Doubling the diameter of a pipe increases its capac- ity four times. A cubic foot flowing a second of time is equal to 50 miner's inches, or 450 gallons a minute. 126 IKRIGATION FARMING. A cubic foot of fresh water weighs 62.5 pounds and contains 1,728 inches or 7.5 gallons. 27,144 gallons of water will cover one acre one inch deep. 225 gallons a minute or 25 miner's inches will be sufficient to cover one acre one inch deep in two hours and one minute. A simple method to determine what a windmill pump is discharging is to measure the actual delivery with a gallon measure for one minute and multiply by sixty. Divide the gallons per hour by 38 to obtain the acre inches per month, or by 13 for the acre inches in three months. These results are not mathematically accurate, but will be found close enough for ordinary computations. They make no allowance for seepage and evaporation. A safe rule for finding the capacity of a cylindrical cistern is to take the dimensions in inches, square the diameter, multiply by the depth, and then by .0034, which will give the contents in United States standard gallons. Thus to find the capacity of a cistern twenty- five feet in diameter and one foot deep, multiply : 300 X 12 X .0034=3672 United States standard gallons. To meusure flowing water in ditches, canals and rivers, multiply the area by the mean velocity of its flow in feet per second, and the product is the volume in cubic feet; divide the number of cubic feet by 1.57, and the result will be the number of miner's inches. CHAPTER XI. METHODS OF APPLYING WATER. The methods of irrigation in vogue are as varied as the topography of the country. So much depends upon the proper application of water that the practice of irri- gation often results in failure unless it has received care- ful consideration and study. The amount of water a crop should receive, the time in its development to ob- tain the best results, the methods of applying water to different crops, together with that skill in accurate and economical manipulation which comes through practice and experience, are some of the important considerations. It has been found that practically a 70 per cent satu- ration of the soil will give the best results. Speaking in a broad way, a soil will retain its own bulk — not its own weight — of water, some soils more and some soils less. Now if fully saturated, and wheat, rje, orchards and vineyards are planted, they will not grow. But if the soil is given 70 per cent of the water which it can take up, so that there is circulation of water and air within the soil, then the plants can take their almost infinitesi- mal drinks of water and grow with the greatest rapidity. The soil carries this water up to the plant and the plant uses a part of it and evaporates it into the air. Evenness of distribution is important. For instance, if there is twice the amount of water on one place that there is in another, the ground will dry unevenly, and the dry patches will be too dry before the wet spots are dry enough to plow, for in irrigating orchards, or any crop that requires cultivation, the plow or cultivator 127 METHODS OF APPLYING WATER. 129 must follow as soon as the ground is in good working order. A bird's-eye view of a well-planned irrigated farm is given in Figure 44. It will be observed that the land lies on a gentle slope over which water may be spread with easy gradient and in equal ratio to all por- tions. The various plats may or may not be fenced, ac- cording to the owner's judgment, and in most cases fences are obsolete except for pasturage. In the use of water it may be estimated that 1000 gallons of water a minute will irrigate an acre an hour of row crops, such as potatoes, corn, etc., and it requires two men to handle this amount of water properly, as it is equal to ninety miner's inches. An inch of water nominallv will cover an acre of land. The cost of irri- gating an acre will vary all the way from 75 cents to $1.50 for a season of 100 days. Water rates in Colorado, where water is rented, are usually $1. 50 an acre per annum, and this rate is fixed by the county commissioners. It is a good rule, in the arid region at least, to have the water running constantly on some portion of the farm, although this is not an inflexible rule on account of the wastefulness which it entails. Old irrigators never shut off the water when a shower comes up. In all irrigating work it is well to imitate nature as nearly as we can. It will be well to remember in this connection that the soil must be adapted to the way, which on the other hand is itself not adapted to all soils. Subsidiary Canals. — Where the supply canal is large and the banks thick, it is well to divert the w'ater from it in only one place. A shallow subsidiary canal may be made parallel wqth it, into which sufficient water is allowed to flow to supply the laterals. It is very easy for a stream to get beyond the control of the irrigator, and he must watch the aperture in the canal bank closely and take measures to prevent this. In the most primitive forms of irrigation the shovel is relied upon 9 130 IRBIOATION FARMING. entirely for regulating the flow of water; but a' step in advance is made by putting in wooden boxes at Buch places, with a simple gate board sliding between upright cleats. In this way the exact quantity of water desired may be diyerted, without danger that too much will force its way through. One advantage of these eubsidiaiy canals is that it catches up the leakage of the main canal and utilizes it for immediate use, and at the same time avoids the discomfitures of seepage waters on the lands to be ii'rigatcd. Sometimes these secondary canals are cemented, and they ai-e useful in governing the water for the furrows by means of bulkheads. These bulkheads may best be fixed perma- nently in position, and if supplied with sluice gates they are ready for use at all times, and will last for years. Fix these boses in the lower bank of the subsidiary ditch at the head of the laterals — and they may also be used in METHODS OF APPLYISG WATEK. 131 the laterals for the furrows just as well. A very good arrangement of this sort is described in Figure 45. Preparation of Land. — Little inequalities in the surface of a field give tiie irrigator more trouble iii the flooding system than do large hills. Jhey are too small to have any provision made for them except such as mny be extemporized with the shovel while the water is run- ning, "When the surfaee can all be brought to an even grade, work is greatly lessened, water is economized and the spotted appearance of the crop is avoided. Grading fields on any large scale has hitherto been impracticable because no machine was made specially adapted to it. One now invented and manufactured by B. F. Shuart, of Oberlin, Ohio, solves the problem, A good idea of this land Icveler is gained from Fig- ure 46. Hesper Farm near Hillings, Mon- '~'- ta*, on which this FIG. 16. DiPHovED sTKEL L,\xD (iHADKB. machino was first put to service, was graded by it so perfectly that the water when turned from the ditch spreads over the sur- face by the mere force of gravity, with a uniformity of effect which reduces the task of irrigation almost to rec- reation. On this farm one man handles 350 inches of water and has time to spare. Grading land practically dispenses with the incessant and exhaustive use of the shovel, incident to irrigating under ordinary conditions. On a well-graded farm the irrigator in applying the water has little need of his shovel, except for opening and closing again the banks of the ditches where he turns out the water. The even grade also makes it pos- sible to run the water farther, and thus reduces the num- 132 IRRIGATIOx'^ FARMING. ber of laterals necessary, and increases the head of water which can be used to advantage. Fifty inches is the head ordinarily used on Hesper Farm. With this ma- chine one man with a team can grade from three to five acres a day on an average. The laterals should be carried to the highest van- tage ground possible and should be opened at convenient points to, allow the water to pass out upon the ground, and in this way it covers the field in seeking its level. The method of making laterals, especially as to the ne- cessity of having them raised above the natural level of the ground, is described in Chapter VI. Time to Irrigate. — Generally all ditches in the temperate zone should be ready to receive water by the 20th of May. The first water is turned upon the pas- ture, meadow, or orchard, just as it may be required. One year in the twenty that we have farmed in Colorado we commenced on the 24:th day of May to irrigate, to ger- minate the grain that had been sown. We irrigated three times that season. We commence generally from the 10th to the 25th of June to irrigate the small grain crop. The matter deleaving water turned on is regulated largely by the condition of the soil. While some land will soak full of water in from ten to twenty minutes, another kind of soil may require as long again to soak. We turn the water on and let it stay until the ground is thoroughly wet and soft as deep as it w^as plowed, — eight to ten inches, — then the water is let out of the ditch a little further on, and so on until the field is all irrigated. Every crop tells when it wants water. The grasses, clovers and small grains have a language that cannot be mistaken. Whenever their green color becomes very dark and sickly turn on the water. When corn wants water it tells the fact by its leaves being curled up in the morning. Salsify needs but little if any water after it is well under way. Carrots cannot bear an irrigation by METHODS OF APPLYING WATER. 133 flooding after they are half grown. If covered with water the crowns decay. All species of the cabbage family require a good deal of water. In other words they like wet feet and are very particular how the water is ap- plied. All plants in a dry climate should be pushed in their early stages of growth by a judicious application of the proper amount of water and frequent cultivations, at no time letting them stand, or go back from want of water and proper attention. Plants in general need much less water than is usually applied by almost everyone. They do far better and suffer much less with two inches on the surface applied two or three times during their growth than they do with twelve inches on the surface applied five or six times in a season. It is a sad mistake to put on too much water. The determination of the proper time to irrigate and the amount of water to apply must lie for the most part with the farmer himself. The humidity or dryness of the atmosphere, as well as the position and condition of the soil, are to be well considered, and common sense is a better guide than is philosophy. If trees are allowed to get too dry the sap of the stalk commences flowing back to the roots, accompanied by falling of the leaves, and water is often turned on too late to save them. On the other hand, if too much water is applied it stimulates a too rapid growth, and the probability is that if not cut back and thoroughly hardened in the fall, they will be found in the spring to be entirely dead, or standing sim- ply an outside live shell with a black and dead heart. Anyone can easily learn just about the degree of moisture in soil necessary for the healthy growth of a plant, and the nearer uniform the condition of the moisture the more vigorous and healthy will be the plant. The best time to irrigate is early in the morning be- fore the sun acquires very great power, or in the evening when it is about to go below the horizon. A good time 134 IRRIGATION FARMING. to water land is when a cloud comes up and a shower is expected. In nine cases out of ten the shower does not give all the water needed, so the work will not be useless- ly expended. Irrigation should not be done in the open when the sun is shining hot, as there is great danger of scalding the plants. If we have a good head of water in the ditch we prefer to begin irrigating at four o'clock in the afternoon, and often keep up the work as late as mid- night, especially on moonlight nights. At the Utah sta- tion the temperature of j^lats irrigated nights was slight- ly higher than those irrigated days. The yield of grain was slightly greater on the plat irrigated in the day time, due probably to the checking of the growth of the foliage. The total yield, or the yield of sti'aw and grain, was some fifteen per cent greater on the plats irrigated at night, and the ratio of straw to wheat was therefore much greater on the plat irrigated at night. Straw to bushel of grain when irrigated nights, 120 pounds ; when irri- gated days, eighty-nine pounds. The Flooding System. — As already mentioned the land must be prepared and made as near even as pos- sible, by scraping down the knolls and filling up the low places so that the water will spread evenly. If it does not spread in this way the irrigator must follow it out with his shovel and conduct* it to the neglected spots. The api)lication of water to crops by the method of flooding is the quickest and cheapest, and hence is almost universally used for grass, meadows and grain crops. On those soils which bake and crack badly flooding is injuri- ous unless the plants stand close enough together to shade the graund well. Water coming directly against the crown is unfavorable to the growth of many plants. It has often been noticed that millet, rye, oats and other crops will be larger and more thrifty a short distance from a ditch bank, where they receive all their moisture by seepage, than they will farther out in the field, where METHODS OF APPLYIKO WATER, 135 irrigated by dooding though kept sufficiently moist. Moat generally in tlie spreading of water over farms — par- ticularly those that have not been properly graded as de- scribed — plow farrows are run diagonally across fields, as outlined in Figure 47. This system is the most prac- ticable to use in fiooding land. The farrows which dis- tribute the water are run in snch direction, required by the lay of the land, as will give them only a slight descent. A hoeful or shovelfal of earth thrown in the furrows at the entrance keeps them closed. When the land needs water the little g^ejor sliding board at the canals is raised as far as ne^d^d to let in the required amount of water. This is raised or lowered as may be necessary in the course of irrigating a field. 136 IRRIGATIOn FARMING. The lateral being filled with water, the irrigator opens the upper ends of the plow furrows by taking out a shovelful of earth. The little furrows then become filled. The water seeping through or running over the sides gently trickles along over the surface and soaks into the ground. Flowing thus from each side the waters soon unite between the furrows and thus tlie moisture becomes uniform and general. The farmer may remove all obstructions by clipping off a bit of dirt at intervals from the sides of the furrows, and flood his land till the water will everywhere cover the surface. In this way he can in an hour or two give an entire farm what w^ould be equal to a heavy soaking rain. These floodings are often given about the heading-out time and the result is the production of heavier and more perfect grain. The water should be put on as rapidly as possi- ble with iio let-up — the quicker the better. It should not be allowed to stand in pools anywhere, because standing water stops all the pores in the soil, cutting off the air from the roots and, as it were, taking the life out of them for some time. Flooding requires more water than many other methods, but at the same time much less labor is needed, and it may be called the lazy man's svstem. Furrow or Rill System. — It is best to irrigate gardens and orchards by the furrow method. An even greater difference comparatively in the quantity of water used obtains in the furrow irrigation of fruit trees and vines than in the case of cereals. To such an extent does this prevail that not only do districts differ, but, of two neighbors who cultivate the same fruits in contigu- ous orchards, having exactly the same slope and soil, one will use twice or thrice as much water as the other. Judging as far as possible from conflicting testimonies, the cardinal principle appears to be just the same. As we have endeavored to show, it is desirable to APPLYING WATEU. ILIT have the lateral taken otit of the maia canal at iv point higher than tlie grade of the ground to be irrigated. A practical example of this diversion of water is to be seen in Figure 48, where a distribating gate diverts the canal water through a lateral to the furrows of an orchard. In garden and orchard work the character of the fnrrow U jToverneJ largely by cirenmstances, and the kind of planting will largely govern one's actions in laying out furrows. Fi-om a general head fnrrow smaller ones are run at right "or obtuse angles into the plantation. A grade of one inch to the rod is usually sufficient, and an orchard should be set with this end in view. In the West we prefer to have the trees set closest together in the north and south rows, so that one tree shades METHODS OF APPLYING WATER. 139 another from the two o'clock sun, which in winter espe- •cially is very damaging to young trees. Always set orchard or small fruit rows to conform to the proper irrigating grade, as this precaution will save much sub- sequent trouble. A new furrow in orchards or vineyards should be plowed every time an irrigation is to occur, for the closely following cultivation which is the most important part of this work will close over and obliterate the fur- rows. Make a furrow on each side of the trees and give an irrigation that is calculated to carry the water well down into the soil — lower than the roots if possible, and for this reason the writer advises sub-soiling before the planting is done. The first year after planting, the rill may be run within a foot of the trees, but the water should never be allowed to touch the trunks. Some horticulturists set out small fruits in rows four or fi. feet apart longitudinally with the trees, while others put such plants as raspberries and blackberries in the tree rows themselves. The advantage of the latter plan is that it affords more shade to the cane fruits, but at the same time they are more apt to receive less water than they need, as cane fruits require more water l;han is given to trees. By planting in the open between the tree rows cane fruits may be irrigated more frequently, and this can be done independently of the trees themselves. As trees grow older year by year their furrows should be carried farther away from the trunks, a good rule being to keep them in a vertical line with the outer tips of the branches. With full-grown trees the irrigat- ing should be done with several parallel intermediary rills, as pictured in Figure 49. This system is much in use in the citrus .proves of Southern California. When the orchard is steep then plant, — not in straight rows, but lay out ditches with a fall of one-quarter of an inch to every rod, and plant the 140 lERIGATIOi^ FARMING. trees along the ditches on the lower side. Professor Blount of New Mexico lays out his orchards on a grade, of one inch to one hundred feet east and west, and on a level north and south. He admits water at the north- west corner of his quincunx plantation, and by double furrows his trees are iiTigated on all sides, as displayed in Figure 50, and by which means his rootlets are uni- formly watered. FIG. 50. DOUBLE FURROW ORCHARD SYSTEM. In all furrow operations it i:^ best to allow the water to trickle gently through them until the land is well moistened at a spade's depth between the furrows. Be- fore allowing to dry, hoe back the earth into the furrows, and cultivate as soon as the land will admit. By irrigat- ing in this way evaporation will be reduced, water will be economized, the earth will be moistened to a depth of at least two feet, and one irrigation of this kind will last as long as two or three by flooding. METHODS OF APPLYING WATER. 141 Underground Flumes and Stand Pipes. — In Southern California, where water is scarce and most eco- nomically applied, the preferred orchard system is that of the underground lateral to couvey the water to the place of its application. The scheme is to have the water delivered by underground cement or iron pipes at the highest point of each ten-acre lot. This delivery is ordinarily made by a cement hydrant or pipe, opening into a flume made of wood, brick or vitrified pipe, extend- ing entirely across the plot to be irrigated. If it be trees or vines that are to be irrigated, there will be from two to eight furrows plowed between the rows at right angles FIG. 51. SECTION OF VITRIFIED HEAD DITCH. with the flume and extending in the same direction with the grade of the land. Flumes made of redwood either V-shaped or square are largely used, and opposite each furrow and opening directly into it an auger hole in the plank is bored, which is covered with a galvanized iron gate set in a slide, the whole thing being cheaply pro- vided but verv effective. The water having been turned into a flume from the hydrant, the slides over the apertures are adjusted so as to allow exactly the amount to escape that is desired. Slow saturation is the desideratum rather than sudden flooding, and by using these gates the flow may be ad- justed to a nicety and the water then left to itself, no 142 IRRIGATION FARMIifG. watching being necessary, and no constant labor with the shovel, as when water is applied from open ditches. Sometimes a substantial flume of brick is laid in place of one of wood, and a square vitrified pipe with openings in the side is also highly thought of. A section of this terra cotta head ditch is presented in Figure 51. Into this flume is turned from the ditch an irrigat- ing head of 20, 25 or 30 inches of water, generally about 20 inches. This is divided by the holes into streams of from one-sixth to one-tenth of an inch, making from 120 to 200 streams. These are run across the tract in small furrows leading from each hole. From five to seven fur- rows are made between two rows of trees, two between rows of grapes, one furrow between rows of corn, pota- toes, etc. It may take from fifteen to twenty hours for one stream to get across the tract. They are allowed to run from eighteen to seventy-two hours. The ground is thoroughly wet in all directions and oftentimes three or four feet deep. As soon as the ground is dry enough, cultivation is begun and kept up from six to eight weeks before water is used again. For trees a year old one fur- row on each side of the row will do, for two years old two furrows, and so on. In many places the outlet from the underground head flume is through a series of stand pipes. An im- proved measuring penstock consists of a four-inch iron standpipe resting on a six-inch viti'ified service pipe. At the summit of this measuring standpipe is a sliding gate on which is a scale so arranged that the amount of water flowing through it can be measured by simply read- ing the scale. A valve inside the standpipe is operated by a screw attachment and admits the proper amount of water, while it can be locked by a simple device. Out- side the standpipe is a pressure gauge which shows the head of water on a measuring slot with a glass face. This contrivance is used in measuring the patron's appor- METHODS OF iPPLYINO WATEll. 143 tionment of water, and in this fact alone does it possess any advantage over tlie simple oponiug in tlie head flume for the eseHi>e of water. The Basin System. — This method consists in makiilg u small Ijasiu around trees, filling it two, three or more times with water as fast us it soaka away. These basins vary in size according to the amount of water one has. Where the supply is small they are often not more than two feet across, and even smaller for young trees. Where there is more water, many make them 10, 13 and even 15 feet across. Some make them square, othoi's round, while others make them ovai or rectangular. The plan is well shown up in Figure 53. In many cases the formation of these basins is very stupid. That trees treated in this way do anything, only provea that they would do better in other ways, and does not prove that such is the correct way to irrigate them. For instance, allowing the water to touch the trunk of a tree is radically wrong. In the center of the basin 144 IRRIGATION FARMING. should be left a mouud of dry soil around the trunk ot the tree, at least two feet in diameter, and three or moi-e would he better. Instead of heaping up earth on the lower side and making a pond of water, of which the pressure will puddle the bottom and prevent the access of air to the roots, by covering it with a hard, tight crust, — the basins should be made in the form of concentric rings ; or, where the hill is too steep in crescents, one above the other, and leading one into the other. The basins may be filled by hose, watering carts or by pipes, but the writer considers the plan scarcely worthy of adoption. Another plan to convey water to the roots of trees is to set a length of sewer pipe, or a two-foot box six or eight inches square, into the ground two or three feet from the trunk. Into this box water is poured until it is filled, or it may be conveyed in a hose and allowed to run for sometime, so as to give the roots a good soaking. It is better to have three or four of these boxes placed Q,round a tree so as to distribute the water more evenly * in the ground. This contrivance is seen along village streets where shade trees are grown. Borders or Checks. — This is a cumbersome method of field irrigation in practice by Mexican farm- ers, but which is gi*adually going out of use. Each bor- der includes a few rods only, and the borders are from six to twelve inches high, which would indeed interfere sadly with the use of machinery. The plats are filled with water, w^hich is quickly run off from one to the other after a thorough saturation of the soil. If, how- ever, the land is well leveled, five or ten acre patches in- stead of a few square rods may be enclosed with borders or ridges, which would be the improved American plan on a Mexican basis. These acres can be enclosed with borders made in such a way as not to interfere with im- plements. The borders can be made into gentle swells, eighr, ten, or twelve inches in the center, and the base METHODS OF APPLYING WATBE. 145 twenty feet. The object is to secure quick and thorongh irrigation. Some have called it the checkerboard ays- tern, but it is the only one that native farmers know, and those crops that they attempt to grow are indeed very prolific. Sprinkling.— In Florida most of the irrigation is of the sprinkling order and is best described by treorge W. Adams, of Thonotosassa, who says: "I have a twenty-flve horse power horizontal boiler and a 13x7x10 duplex pump, with six-inch main pipe and three-inch laterals at the main and running down to one and a half at extreme ends. My trees are twenty-one feet apart each way. I have a hydrant in the center of every six- teen trees. I use the MeGowan automatic sprinklers, connecting the sprinkler with hydrants by a one-incli mire-wound rubber hose fifty feet long, I nse twelve of the sprinklers at one time and could nse more just as well, eaoh sprinkler staying in place thirty minutes, each one covering a space of from fifty to seventy feet, accord- ing to the amount of pressure given them, and discharg- ing about TOGO gallons. By this process I have a gen- 10 146 IRRIGATION FARMING. aine rain, eithei* a light one or a powerful one, at pleas- ure. If I wish to throw water over the tops of the trees, I use the nozzle instead of sprinkler. I run the pump from 7 A. M. to 6 P. M. without stopping, using less than one-half cord of wood in eleven hours. I find no bad results from applying the water in the hottest sun- shine, but would if I applied it through an open hose. I think tlie sprinkler method of applying water requires less help than any other I have seen, and is without any danger to fruit or trees. The fireman can manage the sprinklers within reasonable distance of the pumj)ing station. For other portions only one man is ever needed and it is light work for him." While using the hose in irrigating fields with an un- derground pipe system to supply the water costs more af the beginning, it often proves loss expensive and much more satisfactory in the end. A field irrigated in this way is illustrated in Figure 53. Hillside Methods. — In irrigating hillsides great care should be exercised lest much of the best soil as well as the manures applied be washed away. With slopes at all pronounced, great care should be taken to draw the irrigating furrows across the slopes in such direction as may insure a proper fiow without the danger of washing. No definite rule can be given for this, but a little experience and training of the eye, to judge of the proper declivity to insure a safe flow of water, will soon tell the careful cultivator in what direction to run his irrigating furrows, if the water be applied in that man- ner. A study of Figure 54 gives one a practical idea as to how these furrows may be run and manipulated. Flooding from one furrow to another is a very simple matter and only requires a little experience on the part of the irrigator. Backsetting. — In Western Kansas a primitive system of sub-iri-igation by damming a stream in a flat METHODS OF APPLYING WATER. I'l? country and forcing t!ie water through the adjacent lands by percolation is somewhat i-elied upon bat will not become generally adopted. The water la dammed and simply forced out throngh the banks into the ground, and in this way subterraiiean moisture is afforded tlio Biirfaeo soil to produce good crops. The ]iliin is iiitlier too expensive in dam building to mako it veiy popular. and the operator having no control over the seepage tide would soon find his ground water-logged and too wet for ordinary farm crops. Fall and Winter Irrigation. — In many sections of the West the system of fall irrigation has been prac- 148 IBRIGATIOIf FARMING. ticed with good success. After the crops are all har- vested the water is turned on and the soil is given a thorough soaking. Subsoiling greatly enhances tlie value of winter irrigation, which furnishes moisture for the starting of plant life in the early spring, and causes the weeds and other remnants of the cropping season to more easily decay and act as a top-dressing of fertilizers. The land is also put in good condition for plowing early in the spring. But very few crops should be irrigated from the time of planting till after the plants have had several days' growth. Fall irrigation supplies moisture sufficient to start the crops and gives them a vigorous growth of a few weeks before irrigation is necessary. It is better for young plants to have the moisture come from beneath than from the surface, especially in the early spring, when water for irrigation is several degrees colder than that stored in the soil by irrigating late in the fall. We have found in Colorado that irrigation may be applied advantageously before the regular cold days of winter set in, and this practice is adopted generally by successful cultivators where water can be had at that time of the year. The late irrigation is useful after a dry fall and is especially to be commended in the prepa- ration for crops which require the maximum amount of moisture, and for orchards, or where the water supply is likely to be short the coming season. It places the land in the condition of a storage reservoir for the succeeding season, and experience has shown that the soil that has received a thorough irrigation in the fall or early winter has great advantage over ground that has not. This is true when land is fall-plowed, and the water may be applied either by rills or by flooding. Let it be a good deep soaking. Orchardists are generally adopting this plan for their trees, and thus the evil effects of win- ter drying are circumvented. METHODS OF APPLYING WATER. 149 Foreign Methods. — In China a very primitive way of irrigating is in use. A Chinese farmer's estate is usually a sandy plain with slopes from one end to the other. His first sfcep is to divide it into counterparts by raising low walls or partitions of clay. They are usually a foot and a half thick and two feet high. Where it is diflBcult to get clay he constructs the wall of the stones he finds in the soil, or of broken bricks and tiles, and stops up the crevices with clay or even mud. Any form of soil excepting sand is used in this manner. He even gathers the ooze bared by the low tide with which to build the walls. In each little compartment he builds a ditch in front of the lower wall, and at the comer of the compartment he lowers the wall somewhat for the water to flow from one check to the next adjoining, very much as is done by the Mexicans. When it rains the compartments fill, and the entire field looks like a lot of panes of glass ; the water soaks slowly into the soil and keeps the ground moist enough for agricultural and hor- ticultural purposes for several months. For the irriga- tion of rice lands, which have to be submerged, the lands are divided into small patches at large levees, so that the appearance is that of a beautiful system of ter- races, near a bountiful supply of water, which is raised to the upper level by chain pump and treadmill process with coolie power. In places where there is a scarcity of water the men and women carry, suspended from a yoke across their shoulders, two large buckets with long spouts, and sprinkle rows of vegetables copiously. Some- times the water for this purpose is carried in buckets a considerable distance. Liquid manure is applied in the same way. The irrigation of Egypt is now conducted on a sci- entific basis. The whole country is cut up into canals, and there are immense irrigating works in the delta, which during the inundations of the Nile require hun- 150 IRKIGATIOif FARMING. dreds of tliousands of men to manage them. An im- mense dam extends across the ^We near Cairo, v/hich raises its waters into a vast canal through which they are allowed to flow out into subordinate canals over the great delta. There are some steam pumps used in Egyptian irrigation, but by far the greater part of the country is irrigated now as it was in the days of the Pharaohs. This is by means of the shadoof and sakiyeh. All over Egypt may be seen men naked to the waist standing knee-deep in water with a basket-work bucket hung by ropes between them. With a swinging motion they scoop the water from the river into this bucket and ewing it up to a canal on a higher level, from whence it runs off into the fields. The water is often drawn from this canal into a higher ditch in the same way, and thus })j a series of planes it is conducted so that none is lost. After the water is taken out of the great canals, it is spread over the fields in little ponds, and the flat fields are often divided into small squares by means of embank- ments of earth one foot in hight which run around them like fences, and which can be opened or closed to regulate the hight of the water within them. The ris- ing of the Nile begins in June, and during the summer much of Egypt is one vast lake. It remains so through September, and subsides toward the latter part of October. It is at this time that the water is conducted into this vast network of canals, and is carefully carried over the cultivatable lands. In Spain the system for irrigation of meadow lands most commonly applied in the northern provinces is by inclined channels, or the system of spike channels. The distribution channels are devised nearlv in the sense of the greatest slopeness of the grounds. The irrigation channels connect with them and spread out from right to left. A rapid sectional change takes place in the dis- tribution channels at the point where they separate into METHODS OF APPLYING WATER. 151 branches with the irrigating channels, which by having a gradually narrowing section from their parting point down to the end, pour out the water by getting inundated. Another contrivance is also combined with this dis- tributive system, which consists in collecting channels, called azarbes, dug on the natural lines of junction on the meadow ground, terminating in an outlet channel. Sometimes when the extent of the meadow is not con- siderable, or when the quantity of water available is but small, the collecting channels are changed into new feed- ing channels for the supply of other lands situated far- ther down. They level off the ground so that the water can flow over it easily, without leaving standing pools and mud, or washing out the ground and forming gullies. They prepare their lands so that the water will flow over them easily and safely. They also construct their lateral ditches very well, and when they are through with the water the supply is turned off. They never waste it. They have only a few small reservoirs. In Australia much of the interior land is irrigated mostly through the medium of billabongs or lagoons that are oftentimes supplied from natural streams during the rainy season. The water is applied to the lands much the same as we apply it. In other countries along seashores a system known as warping is customary. By this mode the" tides are received through an embank- ment or dyke and retained until the sediment or warp is deposited. Sub-irrigation is a system that is practiced in all countries, including our own, and as it is of much importance as to detail the writer will treat it in a special chapter later on. CHAPTEK XII. IRRIGATION OF FIELD CROPS. 