y'T", A Publication of The College of Agricultur UN IVERSITY OF CALIFORNIA -'"-'*£? mmmmmmmm i^;!*--^:;^* -<^%j^#^ 1* i^ ', .M^i^rp^>« 'X ^"^te ;ii Homemade'' Devices Regulate Flow, Avoid Undue Washing Native ingenuity comes to the rescue in devising methods and using materials at hand to get the job done. A case in point is the use of such items as rocks, burlap, paper, short boards, slats, weeds, and other materials to regulate the amount of water ad- mitted to a furrow. The upper photograph shows a pear orchard in El Dorado County, and the use of burlap dams. They can be seen in the ditch at the right. The lowest one is placed to divert the stream to the left and into a furrow. (Note: If another burlap dam had been placed midway between the two nearest ones, there would have been less erosion.) They usually are about ten inches square. Occasionally steep supply ditches are lined with burlap. The photograph at left shows the supply ditch run- ning from upper left to lower right. Small rocks are used to regulate the height of water in the ditch, and the directing of water into the irrigation furrows. page FURROW IRRIGATION The Use of Flumes to Contn "^''M The grade of about twenty per cent in this pear orchard in El Dorado County is much too steep to allow usage of a supply ditch. Water from a pipe line is run down a portable V flume — and fed to the furrows, as desired, from one-inch holes in the side. Control is maintained by small slide gates covering the holes on the outside of the flume. Rocks are placed in the flume below each opening, so that they allow a small pool to form, expediting the flow from the hole. Note, too, the small boards placed to prevent water splashing from the flume as it hits the rocks. The flumes are easy to con- struct and easy to move. page 10 Irrigation Water Supply The main irrigation system for this or- chard (below) is a series of concrete pipe lines. The furrows between them are quite long. When the ground has been newly cultivated, as shown, the entire length of the furrow cannot be irrigated without causing some erosion because of the large stream necessary. To avoid such diffi- culty, this owner has built a portable box flume. It is placed in the orchard about halfway between the pipe lines. Thus smaller heads can be run from both the pipe lines and the flume. (The flume is in sixteen-foot lengths, with the bottom board of each tapered so sections tele- scope.) Note the remnants of the recent covercrop which has been worked into the surface soil. &•;>, a^ — *^iSir^ 1^ m^ -^t%^ ^mt i\ mm: FURROW IRRIGATION An Excellent "ZigzoQ" Protective System This walnut orchard in Los Angeles County has been prepared for irrigation with a very effective, yet seemingly com- plicated, furrow system. The furrows "going away" from your vision were pre- pared first, across the slope, and prac- tically level. Those going from left to right in the photograph were made, using a blocking device, so that the water zig- zags through the orchard. This method can be used when the slope is as much as three or four per cent. The slope illus- trated, however, is somewhat less. Because of cultural operations, it is neces- sary to prepare these furrows at least twice each year — once for protection against winter storms, and again for sum- mer irrigation. After harvest, a cover- crop is volunteered or sown, and the fur- rows are reworked. The covercrop and the furrows adequately protect the or- chard against erosion, which frequently results from heavy run-offs caused by storms. The covercrop is worked into the soil in the spring, and the system is prepared once more for summer irriga- tion. If weeds grow too vigorously, the orchard may have to be disked and fur- rowed during the summer. This is one of many effective systems that can be used in stepping water down slopes without danger of washing. :>^> *[^ mmm WiJ^ ^^^ .^^^^mm^^. -f^M ■^'m^,. *l^^^fM^J&A Steep-Slope Irrigation on Adobe Soil Here is a grove of orange trees, planted in adobe soil, with a slope of about six per cent. On drying, the soil cracks very badly. This latter factor eliminates the use of any form of contour irrigation, because contour furrows just would not hold the water. If furrows are used at all, it is recommended that they run straight downhill. Small heads, run for a con- siderable time, give a satisfactory irriga- tion and avoid erosion. The upper photograph shows the metal supply pipe line at the left, with the noz- zles projecting toward the orchard. The lower photograph illustrates cracking of the adobe soil. M^'^ n ^'^w FURROW IRRIGATION Suggestions for Improving This Orchard's Irrigation As can be seen, the Bartlett pear tree shown is stunted. The irrigation furrows have cut deeply into the soil, which is about two feet deep on bedrock. Even if they had not, they would still be inade- quate to wet the entire soil mass. This side-hill orchard could be irrigated suc- cessfully by any of these methods: 1 , Contour Furrows run across the slope on a grade of about one and one half per cent. (At right angles to those shown in the photograph.) Two furrows to the row would be sufficient, because the wa- ter would penetrate to the bedrock, seep down the slope, and wet all of the soil. 2, Contour Ditches, as shown on page 16, could be employed in this orchard at intervals of about 60 feet. The orchard should then be planted to permanent cover. Irrigation water could be spilled over the bank of the ditch every few feet to guarantee complete wetting of the soil. 3. Sprinklers and a permanent cover- crop would be very effective. (See page 18 for details.) However, if most of the orchard can be successfully irrigated by furrows, as described in paragraph one, above, the latter would be a more prac- tical solution to the problem. Small, steep, isolated areas are best handled this way. page 14 IRRIGATION METHODS ON STEEP LAND STRIP CHECKS OR BORDERS Clever Adaptation to Prevent Wasting Water Most irrigated pastures are planted on soils with hardpan or dense clay subsoils. The Ladino clover pasture shown below is an excellent example of a relatively new method of land preparation for the maxi- mum usage of irrigation water. Formerly the land was graded so that the strip checks ran all the way to the drainage ditch. The length of time necessary to run the water in the strip checks in order to get good penetration often resulted in great waste. The new method of leveling is shown in the sketch below. The ridges extend only to the basin. The excess water from the checks irrigates the basin, shown in the foreground of the photograph. The small amount of excess water runs into the drainage ditch. DRAINAGE WATER PENETRATION «t. . . page 15 CONTOUR DITCHES Successfully Irrigated Pasture Rather steep land can be utilized for irrigated pastures if proper methods are used. The technique pictured and described here is a very simple and very successful one. i^- .#' ^^ The photograph shows a ditch with a grade of about one half of one per cent. The water spills over the lower edge. Ex- cess water collects in the next ditch which is usually about 75 feet below, supple- menting irrigation water in the second ditch, and so with others down the grade. Judgment must be used to assure com- plete irrigation; ditches must be spaced close enough to wet the entire area. page 16 . IRRIGATION METHODS ON STEEP LAND on Hillsides The pasture shown in the photograph be- low is a good example of the use of con- tour ditches. Note how the dry pasture at the crest of the hill contrasts with that irrigated. The light patches in the right center of this picture indicate dry areas — the probable result of the ditches being too far apart to wet the entire area. Orchards, too — Deciduous orchards can also use this irrigation method in con- junction with a permanent covercrop. Under these conditions, how- ever, the ditches must be steeper, because the unpastured vegetation tends to clog them. Caution should be exercised when permanent covercrops are used in or- chards. Gophers become a problem, as it is not easy to detect their workings. Field mice sometimes build nests at the bases of trees, and girdle them. The rodent problem should be given consideration before the adoption of a permanent covercrop program. page 17 SPRINKLER IRRIGATION Sprinkler System Replaces Furrows in Pear Orchard From clean cultivation and irrigation by furrows, a Placer County orchardist switched to permanent covercrop and sprinklers. The orchard is on a slope of about five per cent, with soil about twen- ty-two inches deep on bedrock. Result of the old system was uneven application of irrigation water and soil erosion. The new technique has proved very successful. Irrigation water is delivered at a high point, so pumping is unnecessary to de- velop pressure. The water is distributed through an underground three-inch pipe, equipped with outlets for the portable sprinkler line. Each irrigation starts at the upper edge of the orchard, with the portable line moved progressively downhill — wetting every other middle. When the lower edge of the orchard has been irrigated, the sprinkler line is moved once again pro- gressively up the hill, and the alternate middles are irrigated. Thus complete wet- ting is accomplished. The covercrop is predominantly Ladino clover, ryegrass, and orchardgrass. It is mowed and left in place each year just before the props are put in the orchard. Once again, caution is advised with re- gard to careful control of rodents who may take up habitation in the covercrop. ^^ ^ page 18 BASIN IRRIGATION Methods Used for Irrigating Young Fruit Trees ^ During the first jew years after planting, the root systems of trees do not develop to the point where they occupy the entire soil mass in an orchard. It is unnecessary, therefore, to irrigate the middles of the rows during this period. Tanking — shown in the top photo- graph — is simply the use of a circular basin around the tree, and watered as in- dicated. A long narrow basin is shown below, and the photograph explains this second method pretty well. A third tech- nique is the running of a single furrow close to the tree rows, with a circular fur- row around each tree. As the root systems enlarge each year, the irrigated area for each tree should be in- creased. Generally, such partial irrigation should not be used more than two or three years for most trees. Widely spaced walnut trees, as shown in both photo- graphs, can be wetted in this fashion for a longer period, however. Caution: Citrus and avocado trees should not be treated so that the irrigation water comes into direct contact with their trunks. Nor should the earth be mounded against the trunks. A circular basin, with the inner margin a few inches from the tree, is recommended. SIGNPOST FOR THE FUTURE- guide ior today Thousands of farmers — this year and every year — are using the services of their County Farm Ad- visors. These specialists know your county, your crops, your farming problems. They are interested in helping you. The service is yours — use it. CALIFORNIA AGRICULTURAL EXTENSION SERVICE COLLEGE OF AGRICULTURE • UNIVERSITY OF CALIFORNIA Cooperative Extension work in Agriculture and Home Economics, College of Agriculture, University of California, and United States Department of Agriculture cooperating. Distributed in furtherance of the Acts of Congress of May 8, and June 30, 1914. J. Earl Coke, Director, California Agricultural Extension Service. 20m-6,'51(6769)L.B.