UNIVERSITY OF CALIFORNIA COLLEGE OF AGRICULTURE AGRICULTURAL EXPERIMENT STATION BERKELEY, CALIFORNIA CIRCULAR 312 March, 1928 PRINCIPLES GOVERNING THE CHOICE, OPERATION AND CARE OF SMALL IRRIGATION PUMPING PLANTS C. N. JOHNSTONi INTRODUCTION The development of agriculture in California depends almost entirely upon the progress made in irrigation. Many thousands of acres in the state would be unavailable for growing the crops giving the higher returns, were it not for the water supplied by irrigation pumping plants. All of the standard types of pumps are used to some extent in irrigation. The four outstanding types now in use for irrigation are the centrifugal, the deep well turbine, the screw, and the plunger. Air-lift and rotary displacement pumps are found occasionally, and serve only small irrigated areas. GENERAL DISCUSSION OF PUMPS Pumping for irrigation dates back to the beginning of history when men or beasts of burden supplied the power that moved water by one means or another. Many machines were developed in Egypt and India for this purpose long before the age of mechanical power ; today some of these are used in modified form in California. With the invention of the steam engine and the demands made by coal-mine owners for better pumping machinery late in the eighteenth century, progress in the mechanical powering of pumps began. Since this time the use of mechanical power as applied to pumps has increased rapidly. Today in California about one-sixth of the electrical power Junior Irrigation Engineer in the Experiment Station. Eesigned July 16, 1926. Z UNIVERSITY OF CALIFORNIA EXPERIMENT STATION produced in the state is consumed in driving irrigation pumping equipment. This does not take into consideration the pumps driven by fuel-oil engines. Pumping originally consisted of filling some sort of container or carrier by immersion in a body of water and then transporting the retained water to a higher elevation. Some pumps use this process today. Others are not immersed in the source of supply at all but are connected with it through a suction pipe only. In these instances the operation of the pump creates a reduction of pressure, or partial vacuum, within itself, causing the water at the source to be forced into the pump by the greater pressure of the air outside. The amount of vacuum or reduction in pressure that must be produced in order to raise the water to the pump is roughly equal to the pressure that is produced by a column of water equal in height to the vertical distance between the center of the pump and the surface of the supply water. A perfect vacuum is a total lack of pressure, and if such a condition is created in a pump, the water will rise from the source a vertical distance of about 34 feet, at sea level. This distance decreases as the elevation above sea level increases, because the weight of air diminishes with increase of elevation. It is not desirable to place an irrigation pump more than 15 to 20 feet above the water source, because friction in the suction pipe consumes some of the pressure difference created by the pump when in operation. Every mechanical contrivance wastes a certain amount of power within itself in the performance of its task; this is of course true of all pumping equipment. The power delivered by pumping equipment divided by the power supplied to it gives a ratio which, when expressed as a percentage, is known as the efficiency of the plant. In other words, the efficiency of a pumping plant is a measure of its behavior while in operation. When the efficiency is low, the. pumping cost is higher than it should be, because more power is being wasted than is necessary. Pumps located above the source of water supply must be capable of 'drawing' the water to them when they are started empty, or if incapable of so doing, both the pumps and the suction lines must be filled with water previous to starting; that is, they must be primed. This is accomplished by the use of a hand pitcher-pump or equivalent power-driven unit, connected to the highest point of the pump case, by means of which the air is withdrawn from the pump and suction pipe. The discharge valve being closed during this operation, the water rises from below and replaces the air as the latter is withdrawn. CIRC. 312 J OPERATION OF SMALL IRRIGATION PUMPING PLANTS 3 Or, the priming may be accomplished by filling the pump and suction pipe with water from some available supply, a flap valve being located at the bottom of the suction pipe to prevent the loss of the priming water. When the first method is used, the discharge valve is opened automatically or by hand as soon as the pump is started. If the second is used, the flap valve, or foot valve, opens automatically as soon as the pressure of water above is relieved. Pumps whose operat- ing parts are submerged in the source of supply require no priming. CENTRIFUGAL PUMPS The types of pumps used in irrigation in California obtain their names largely from their method of applying power to the task of moving water. Of the chief types used for irrigation, the centrifugal was the first produced in this country, having appeared in Boston in 1817. It was called the Massachusetts pump and was made very crudely. It had as an impeller four straight paddles or vanes, which have been replaced in the modern pump by the curved vanes, forming smooth passages for the water. Its principle of operation, however, was the same as that of the present-day centrifugal pump, the water in both cases being forced through openings in the impellers by centrifugal action caused by their high speed of rotation. In the centrifugal pump, in other words, as the water is thrown out of the impeller it creates the partial vacuum necessary to draw in more water and thus continue the operation. Centrifugal pumps may be obtained to operate against low or high lifts, and to discharge almost any desired quantity of water. When they have been purchased to fit the operating conditions, they show very good efficiencies. Because these pumps are accessible at all times and can be inspected and kept in repair, the efficiency may be maintained indefinitely unless the impellers are subject to excessive wear from abrasive material in the water. The cases, or housings, of these pumps are supplied either as solid or as split castings (fig. 1). The solid type has a plate bolted on the side, which, when taken off, permits the removal of the shaft with the impeller on it. The split type opens on the center line of the shaft, exposing bearings, shaft, and impeller. In either case, the impellers may be of the open or closed type. The former type is more common with the single-suction solid-case pumps. Open impellers, as the name implies, are simply impeller vanes mounted or cast against one disk or hub. Closed impellers have their vanes mounted between two disks. 4 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION They provide better guidance for the water than the open type and are generally more efficient. The suction-pipe connections in these two types differ, as a rule. In the solid-case pump, the suction pipe enters the center of one side of the case, so that the water passes into the center, or throat, of the impeller on one side only. In the split-case pump, the suction line is in the same plane as the impeller, at right angles to the shaft, and the pump casing is so built as to lead the water around both sides Fig. 1. — Typical pumps. (1) Split-shell centrifugal pump opened for inspec- tion; (2) single-suction centrifugal pump opened for inspection; (3) deep well turbine model with runners and shaft exposed, full-sized bowls and runner being shown in front; (4) single screw from deep well pump; (5) rotary dis- placement priming pump. (The pump appears just above the number.) CIRC. 312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 5 of the case into the two throats of the impeller. Double entry of the water into the impeller tends to balance the thrust of the water stream entering it — a considerable advantage for this type of construction not usually obtained in the single-suction pump. Previously the solid-case pumps were often made with two suction pipes, accom- plishing the same result as the present split-case pump with its divided channels within the case. Special thrust bearings are fre- quently placed in both types of pumps to take up any unbalanced forces on the impellers. The losses in efficiency in centrifugal pumps are attributable to air leaks, water slippage, and undue churning of the water. The first cause may be eliminated through occasional inspection of the packing glands and suction-line connections. The second, in so far as possible, is taken care of by correct design, all passageways that can permit leakage between discharge and inlet of the impellers being made as narrow as possible, and in some cases being made extra long by the insertion of grooved rings. For this reason, an impeller should not be allowed to rub on the side of the case because of the resulting wear, which is accompanied by excessive internal leakage. Churning, the third cause of low efficiency, is the natural result of operation and may be corrected only in part by proper design and correct speed of rotation. This last factor is especially important because the cen- trifugal pump is designed to operate at a given rotative speed against a given lift, and to throw a predetermined quantity of water. When the speed is changed, therefore, from that for which it is designed, the pump cannot show its best performance. Churning often arises where the pumping lift has remained constant and the discharge has been increased by raising the speed of rotation of the pump consider- ably above the rated number of revolutions per minute. As has been previously stated, irrigation pumps not immersed in the supply source should be located not more than 15 to 20 feet above that source, and for this reason, as the water level recedes, the pumps must be lowered or they cease to operate. In most cases when cen- trifugal pumps are used to lift water from wells, they must be set in pits at the time of installation. These pits are expensive to con- struct and are often dangerous. It is desirable to make them as small as possible. For these and other reasons, centrifugal pumps have been developed with vertical shafts which permit their operation from the ground surface. Pumps with long shafts which are often used in deep pits, however, are subject to much trouble, and, conse- quently have been largely replaced by the deep well turbine and other true deep well types. UNIVERSITY OF CALIFORNIA EXPERIMENT STATION DEEP WELL TURBINE PUMPS The turbine pump is a form of the centrifugal, in which the pump case contains stationary curved diffusion vanes that lead the water away from the impeller to the discharge opening with a minimum of turbulance, receiving the water from the impellers at high velocity and passing it on with reduced velocity and increased pressure. Deep well turbines (fig. 1) have been developed to meet the requirements associated with pumping from wells of limited diameter. They are built to operate on a vertical shaft with a single unit or bowl, or with several mounted in series, one above the other, the stationary curved vanes in the case turning the water from the impeller upward to the bowl above, or to the discharge column pipe. Because this form of pump is limited in size by the well it must enter, it is necessary to forfeit part of the good characteristics of operation possible in the centrifugal or turbine not so limited, but giving an equivalent discharge. For instance, under present practice, the deep well turbine may be operated against a head of about 25 feet per bowl, or stage, whereas the centrifugal or turbine designed for use outside a pit may be capable of operating at triple this head per stage. This is the reason for mounting several bowls in a series in a deep well turbine when the pumping lift is more than 25 feet. The present tendency in design is for higher rotative speeds, resulting in higher heads and greater discharge capacities per bowl. The deep well turbine is always mounted with the bowls below the surface of the standing water in the well, so that it is always ready to operate without priming. This distinct advantage is offset, however, by the fact that these rapidly rotating parts are buried in the well, and very often receive no attention until they fail to operate. Since minor adjustments are likely to be needed in any mechanism that rotates at high speed, the efficiency of the deep well turbine is often lowered because repairs are not made, owing to the inaccessibility of its moving parts. Considerable difficulty arises from the fact that power for the deep well turbine must be transmitted through a long shaft. Manufacturers have adopted many expedients for overcoming this difficulty. Some pumps have enclosed drive shafts, in which the bearings of bronze or other special material are mounted, while others eliminate the bearings entirely and provide wooden guides which extend practically the whole length of the shaft, to prevent flopping or whipping. Others ClRO. 312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 7 accomplish the same result by placing rubber guides or bumpers at intervals along- the otherwise exposed shaft. These do not require oiling (fig. 2). The lubrication necessary to these long drive shafts, which are mounted on bearings, is accomplished by several means. Some shafts are made hollow in order to carry oil to the bearings; others use the drive-shaft housing for this purpose. The bottom bearing of the deep well turbine is of such great importance that a special line is Pump co/umn Open bearing in spider frame screwed info pump co/umn fnc/osed metu/lic bearing joining fyvo sections of drive shaft bousing Drive shaft bousing Drive sbofl, no bearings ■Dpi 'it yyood liner yvitb bo/byv core for s-faft Metallic bousing for liner and drive shaft or -H £bbber beo'W bumper Metallic spider frame screwed into pump "column and supporting Fig. 2. -Various types of shaft-bearing construction for deep well turbine pumps. sometimes run down outside the pump to effect its lubrication. In other instances, the bearing is packed with grease when assembled and is repacked only when repairs become necessary. Since all of these devices are liable to failure, they should be inspected whenever possible. Rapid deterioration of bearings often results from gritty materials which are contained in the water being pumped and which become mixed with the lubricating oils. These turbine pumps may be purchased for either belt or direct connection to the power unit for lifting water any desired distance. Some installations at present approach lifts of 500 feet. When kept in good condition mechanically, they operate with very good efficiency. UNIVERSITY OF CALIFORNIA EXPERIMENT STATION SCREW-TYPE PUMPS The screw-type pump is an application of the principle used by Archimedes to move water upward on an inclined plane turning on a movable shaft. There are several types of the screw pumps in use in irrigation. All involve fundamentally a rapidly rotating- section of an inclined plane, although some have several planes on a common hub. Their action in water is the same as that of an electric fan in air, which slides the air forward from its rotating, inclined vanes (fig. 1). Some are used for heads of less than 10 feet, moving large quantities of water ; others are used for medium to high lifts in wells. The low-lift screw pump falls into two classes, those whose drive shafts are horizontal and those whose shafts are vertical. The units with horizontal-drive shafts are very large and are used where large quantities of water are to be raised a short distance. The low-lift screws on vertical shafts are mostly smaller-capacity ditch pumps, which lift the water a few feet out of the ditch onto the land. Some of these pumps are very crudely made, being merely a screw mounted at the lower end of a shaft enclosed by a rectangular housing and supported on one bearing placed at the top. Their efficiency is low, and were the lift greater they could not be operated at all because the cost of power would be too high. Other designs set in carefully planned housings and having substantial bearings show very good efficiencies, and because of their simplicity, are readily repaired and kept in gcod condition. The deep-well form of screw pump is a series of low-lift pumps so mounted on a single shaft that they operate as a unit. They are assembled from sections about 6 feet long. Each section has two screws mounted in it with a single bearing which is supported in a spider frame between the two screws. The planes of the spider tend to keep the water from whirling as it travels upward. A second set of vanes is placed above the upper screw in each unit to stop the whirling action of the water leaving that screw. When it is desired to pump against a head at the surface of the well, a number of screws are nested at the bottom of the pump because the total lift per screw cannot exceed about 4 feet and should be about 2 x /2 to 3 feet, under which conditions this type of pump operates with very good efficiency. Screw pumps are subject to the same difficulties as the deep well turbines with their long shafts transmitting the power. Since it is impossible to line the drive shaft and bearings with screws located UlRC. 3 12 J OPERATION OF SMALL IRRIGATION PUMPING PLANTS 9 along the length of the shaft, the bearings are open to the entry of abrasive substances in the water. This disadvantage is balanced by the adaptability of these pumps to changing water tables, because sections of pump added at the top or removed from the top, as the conditions dictate, will enable the pump to follow the water levels. In contrast, the turbine requires complete withdrawal for changing the bowls whenever a lowered or raised water table necessitates it. As in the case of the turbines, the screw pump is liable to be operated when repairs should be made. It requires no priming, since the operating parts are immersed in the water supply. As a general rule, screw pumps will handle more water than deep well turbines of the same outside diameter. V/////////////////////////////////Z77Z7 /. L Moving piston w//W////w//////////////////////mn V//////////A Discharge '////////////A ^ZZZZZZZZ^ Joe f ion '////////////A Fig. 3. — Simple plunger pump. PLUNGER PUMPS The plunger pump may be obtained in many styles, but its use in irrigation is limited by the fact that its capacity is relatively small. Fundamentally all plunger pumps are pistons sliding in close-fitting chambers (fig. 3) with two valves so arranged that one opens when the piston creates a partial vacuum in the chamber, the other being forced shut. The reverse occurs when the piston creates a pressure in the chamber. The suction line connects to the port over the valve that opens under vacuum and the discharge line connects to the port over the valve opening under pressure from the piston. The many designs of plunger pumps, both power and deep-well types, are all applications of the fundamental type either for use in wells or for service at the surface of the ground. Deep well plunger pumps are used in areas where only a limited supply of water is available at a considerable depth, supply- 10 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION ing water to a limited area per pump. They operate very efficiently against any head when new and if moving clear water, but they are subject to excessive wear along the close-fitting surfaces if the water contains abrasive material. They require constant attention under these conditions as they soon cease to function economically after wear starts. They do not need to be primed to start pumping if they are in good condition. In fact, small plunger pumps are used as priming units for centrifugal installations. AIR-LIFT PUMPS The air-lift pump, as its name implies, uses air to lift or float the water from the source of supply. A compressor injects the air, which is sent to the bottom of the pump through a line of pipe let down vertically into the water. The pipe enters the bottom of the larger pump pipe column (fig. 9) . The air carries out with it as it rises to the top of the pipe, a certain amount of the water. For correct operation, at least two-thirds of the length of the pump must be below the surface of the water supply. When the discharge is at some point above the ground surface, a still greater portion must be submerged. Even with the best of conditions, an air-lift pump has a very low efficiency. Its application in irrigation is, therefore, very limited. It should find increasing use, however, in the development of wells, since there are no moving parts to be injured by abrasion. ROTARY DISPLACEMENT PUMPS The rotary displacement pump is another device limited somewhat in irrigation use by lack of capacity. Though it is made with many forms of internal design, all are dependent upon the rotary motion of eccentrically shaped or gear-like impellers that turn in the pump case in close-running fit. Because of their shape, they mesh to seal off part of the water in the case at a certain point in their revolution and then, turning further in mesh, eject the water into the discharge pipe (fig. 1). As they are capable of creating a considerable partial vacuum if they are kept in good condition, they do not need to be filled with water to start pumping, provided they are not too far above the supply source. They are occasionally used to prime centrifugal pumps. Because the action of the pump depends upon the close fit of the impellers, the inclusion of abrasive material in the water being moved is disastrous to their operation. They require constant atten- tion if the water they handle carries such material, this being their ClRC-312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 11 chief disadvantage. They show a good efficiency Avhile the running parts are tight but drop off rapidly when wear starts. This type of pump is not applicable to deep well pumping. CURVE SHEETS It is the custom of salesmen in speaking of a pump to refer to its curve sheet. Such a sheet is very useful because it gives a graphic picture of the operation of the pump in question. Figure 4 gives curves for one pump at the given speed and the efficiency discharge curve of a second at that same speed. To use the curves one proceeds in the following manner : 200 300 400 £00 600 700 Discharge in gat/ons per minute Fig. 4. — Curve sheet for centrifugal or deep well turbine pump; speed 1165 r.p.m. The solid lines refer to the first pump. The dotted line is the efficiency curve for the second pump, which shows an undesirable curve for conditions of varying pumping heads. Each curve represents the relationship of two factors; e.g., each of the curves labelled "Plant efficiency — Discharge" represents the relationship of the efficiency of one of the plants to its discharge. First, note that the three solid-line curves are drawn for a pump when turning at 1165 revolutions per minute, for which speed it was designed and at which speed it operates best, If driven at any other speed, this pump will have different sets of curves. Also note that the horizontal base line is scaled to read discharge in gallons per minute, while the vertical line indicates pumping head, plant effici- ency, and horsepower to motor. The most important thing shown in the plant-efficiency — discharge curve for the first pump is that when the highest point of efficiency 12 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION or 60 per cent, is reached at 460 gallons per minute discharge against 98 feet pumping head, the input horsepower to the motor will be 18.5 horsepower. If the head pumped against is not at this point, the efficiency is lower. The single dotted line indicates the efficiency- discharge curve of the second pump. It illustrates a. characteristic design, in which a small change in head or discharge will create a large change in efficiency, as compared to the first pump whose efficiency curve is not so steep. It is evident, therefore, that the second pump is less desirable than the first where pumping lifts are likely to vary. A prospective pump owner, then, should buy a pump having a flat- topped efficiency-discharge curve, if his water levels are liable to vary. Where constant lifts are assured, a sharp-pointed efficiency curve is not objectionable, if the point of maximum efficiency fits the operating conditions. When pumping lifts are sure to increase, the pump should be purchased to operate, when first installed, at a point to the right of the point of maximum efficiency rather than to the left. The operating conditions will then become constantly better for a time after installation. THE SELECTION OF MACHINERY The above description of the different types of irrigation pumps has indicated that each type is adapted to some particular condition, such as high or low water table, or large or small discharge. There are, however, so many makes of pumping plants available that the buyer is often at a loss to determine which to select. He should first consider his power unit, which will be driven through a belt if a fuel- oil engine is selected. Since pumping is a steady load on an engine, the latter must be large enough to drive the pump. Unless over capacity is allowed, the life of the engine is materially shortened. This is particularly true in the case of light-duty engines such as those coming from pleasure cars. If an electric drive is to be used, the buyer must determine whether it is to be direct or belt connected. Though both connections have advantages, the direct insures positive speed maintenance and eliminates some loss. The make of pump selected should depend upon the service obtainable from the sellers in the given area, provided that the products of several reputable manu- facturers are represented. A standard form of agreement 2 to cover the sale and purchase of irrigation pumping equipment has been drafted by a committee 2 Moses, B. D., and L. S. Wing. Farmers' Purchase agreement for deep well pumps. California Agr. Exp. Sta. Bui. 448:1-46. 1928. CIRC. 312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 13 representing the pump manufacturers, the California Farm Bureau Federation, and other organizations. No buyers should fail to' see that his sale contract follows the standard form. Since this agree- ment is in substance a guarantee of the performance of the plant purchased, it affords protection to sellers and manufacturers, as well as consumers, throughout the state. Some satisfactory form of written agreement as to performance should be given with every purchase of a plant. WATER SUPPLIES As was indicated earlier in this circular, there are two sources of water for irrigation, namely, surface and underground waters. Underground supplies are located in the gravels and sands laid down by the streams of ancient times. They are supplied by percolation from the rains and streams of the present day, mainly the latter. Many of these streams of years ago sprang from the same hills and mountains as those of today. The beds of the present streams, therefore, often cut the old gravel and sand deposits on the mountain sides and much of the water in the stream sinks into them, to be recaptured only by pumping. Because these gravels and sand strata are often supplied by waters flowing at a high elevation, they are sometimes found in the valley floor under sufficient hydraulic pressure to cause the water to flow out of the well. Most of them are under some hydraulic pressure, so that the water rises part way up the well casing, at least, when the strata are encountered. Wells of this type are called artesian wells whether they flow or not. Since the water travels slowly through these water strata, irrigation pumping often tends to take the water faster than it can be supplied. The pressure in the strata is thus reduced and the pumping level lowered. When the draft is large, this lowering is often felt in every well drawing from the same strata. Unless the winter rains and the streams can replenish the supply during slack pumping periods, the drop may become permanent. The water table may continue to be lowered in heavily pumped areas until pumping becomes uneconomical. The sinking of wells to develop underground waters has led to the production of a special class of machinery. A large soil auger is used to bore into the earth. Sometimes a scow or sand bucket is oscillated up and down in earth and water in the hole, gathering in a certain part of this mixture through a flap valve located at the bottom. Heavy drills or rock bits that pound their way downward are used in areas va/ve Cutting Mn/ves a D f^r> ,4 Scow or Sbnd pump 3 duger or boring too/ C Pope sochef D Pope sockef sub £ Uars or /iommers F Scow or fbmp *?ub O Pock bif Fig. 5. — Types of well-drilling tools used in California. ClKC. 312J OPERATION OF SMALL IRRIGATION PUMPING PLANTS 15 where rock or boulders are encountered, the loosened material being brought to the surface with a sand bucket. Heavy drilling is further aided by the use of massive jars or hammers, which give an additional blow upon the bit or scow (fig. 5). These tools are operated by well ^m Fig. 6. — Typical well rig used for heavy drilling. Note scow being dumped. rigs, consisting of a portable power plant with a tower at one end (fig. 6), over which a cable is run for the operation of the scow or similar tools, and for the withdrawal of the auger-type tools. The augers are actuated by a turn table, powered through a chain or belt 16 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION drive from the well rig. The hole made by the drilling tool is gener- ally lined with metallic casing forced down as rapidly as space is provided for it below. Casing is usually either screw-joint pipe or so-called * stove-pipe' casing. Both may be obtained for almost any sized well. Stove-pipe casing is made from No. 18 or thicker sheet-iron in 2-foot sections which are lapped over each other for half their lengths to form a pipe whose surfaces are smooth inside and out, and whose walls are a double thickness of the sheet metal used. Variations of these two types are in use, but not generally in California. One of these, a single-riveted casing, is used to some extent in the smaller wells. It is made of a single thickness of fairly light sheet-iron. While the well is being drilled, a record must be kept of the position of the water-bearing strata encountered, in order that the casing may be perforated in these areas. Perforating is done by the well rig, unless manufactured perforated casing has been obtained for direct insertion into the well while drilling is in progress. Many contrivances have been used to perforate casing, including both cutting knives and punches, but none have been found entirely satis- factory. Some wells are never perforated. These depend upon the flow attainable from the bottom opening alone and are called open- bottom wells. It is only occasionally, however, that a sufficient supply can be obtained from this opening alone. On the other hand, it is common to seal the bottoms of wells taking their supply through perforations, making them closed-bottom wells. The perforations are slits or regular-shaped holes in the walls of the casing and are arranged more or less uniformly about the circumference of the well opposite the water-bearing strata. Unless sufficient openings are made in the casing, the resistance to flow through it will be excessive, and the water will be unduly lowered, thereby increasing pumping costs. One special form of well consists of a hole large in diameter and sunk with a rotating auger or drill, from which water is ejected. The water washes the loosened materials from the well. Into this hole a casing of smaller diameter is inserted, the outside of which is surrounded with coarse clean gravel. This method is used to provide a greater area of entrance for the ground-waters, since the whole casing may be perforated. The clean gravel cylinder on the outside permits easy access to the water. The drilling process, how- ever, may puddle the walls of the well, thus defeating the purpose somewhat. In some localities where the materials penetrated are self-supporting, wells may not require casing. CIRC. 312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 17 Almost all wells when first completed require developing. That is, they must be pumped for a considerable time to draw the fine particles of earth away from the water strata into the well and out through the discharged stream. After the fine particles have been removed from the water strata, the flow usually increases, because the water can pass through the strata more readily. The discharged water also becomes clear. As has been previously suggested, the air-lift can be used very satisfactorily for developing wells because it has no moving parts. Deep wells should be developed before the pumping equipment is ordered. Such a practice would greatly lengthen the life of the equipment. The pumps would then operate at higher efficiencies, since they could be purchased to meet known conditions of operation, and would not be subjected to the abrasion incident to the development of the wells. WELL AND PUMP TESTS After a well has been developed, it should be tested to determine the depth to water when the desired discharge stream is being obtained. This is important because these measurements indicate the character of the well. If possible, the test pump should be run at several different speeds, readings of discharge and depth to water being obtained for the well while the pump is operating at each speed. In this way, the actual tendency of the well can be determined and the pumping lift for any discharge can be estimated. This type of data is plotted as a curve (fig. 7) enabling one to know fairly accur- ately what the probable conditions of operation will be beyond the range of the observed data. The curve in figure 7 is typical of nearly all wells in California. That is, the water stands in the well at a certain depth ; when pumping is in progress, this depth increases as the amount being discharged increases. The amount of change in depth, or draw-down, with changing discharge is not the same for all wells, but depends upon the ease with which the water passes through the water-bearing strata and the well perforations. The more easily the water moves into the well, the smaller will be the change in water level for any given discharge rate. The guesswork usually practiced for determining these data cannot possibly fit a pump to a given well accurately. It is as important to test the new pumping plant when it is in place as it is the developed well. Since there is always a chance for a slip in the installation of machinery of any type, it is to the advant- 18 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION age of the owner, seller, and power company to test every new pump installed. Such a test should cover the following items: discharge, pumping lift, power requirement, and, of general interest but not entirely necessary, the speed of rotation of the pump and motor. Discharge may be obtained as follows: Allow the discharge from the pump to fall into an open ditch, across which has been constructed a bulkhead with a weir notch, similar to that shown in figure 8. Make sure that the ditch is large enough so that the water may approach the weir without undue haste or turbulence. Be sure that so 46 ( 7/?or -acte risli s C jrve ' of a ft 'ell 46 \ M ^4a %3S §36 t o c 30 as £6 <£W £50 30O 350 400 450 500 Discharge in Oollons per Minute 550 600 Fig. 7. — Curve resulting from plotting well-test data. the weir crest is horizontal and the bulkhead perpendicular to the ground. Place a small stake a few feet back from the weir and beside one bank of the ditch, with its top just level with the crest of the w r eir, as shown in figure 8. A carpenter's level may be used to set the stake correctly in relation to the weir crest. A ruler held perpendicularly with the zero end resting on the top of the stake will indicate the depth of water flowing over the weir. The discharge may be determined by inspection of the accompanying weir table (table 1). The flow in gallons per minute for weirs of different widths is indicated opposite the readings of head in inches, as measured on the stake in the wier pond. The flow found in the table corresponding to the measured head for the weir used is the discharge for the pump. CIRC. 312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 19 The method of measuring the pumping lift varies somewhat with different types of pumps, on account of the different uses and mount- ings. In the case of such pumps as the centrifugal, whose suction and discharge lines are completely accessible, the following methods of measurements are followed. A vacuum gage is mounted on the suction pipe as near the pump as possible ; if the discharge line extends to some distance from the pump, a pressure gage is tapped into it also, %W^ bulkhead set \\\:^Kjnto d/'fch bank Beye/ed edge of yve/r up stream Fig. top or~ stoke /eve/ with ""^ cr&st of weir 8. — Rectangular weir in place. A indicates necessary clearance of five or more inches between edges of weir and ditch banks. close to the pump. The sum of the readings of these two gages con- verted into feet, plus the vertical distance between the centers of the gages, gives the pumping lift. If the water is discharged from the pump close at hand, the pumping lift becomes suction-gage reading in .feet, plus the vertical distance from the suction-gage center to the center of the discharge pipe at its highest point. In the case of pumps whose suction and discharge lines are inacces- sible, the pumping lift may be calculated roughly from pipe-friction tables, adding the measured vertical distance between the highest TABLE 1 Discarge Table for Eectangular Weirs Head Discharge in gallons per minute for crests of various lengths inches lfoot 1.5 feet 2 feet 3 feet 4feet 2% 131 197 264 399 534 2H 140 212 284 428 575 2M 2% 2V% 150 227 304 458 615 161 242 325 489 655 171 258 345 521 696 3 181 273 367 552 741 $ 192 290 388 588 785 203 306 410 619 830 3^ 214 323 433 655 875 VA 225 340 458 687 920 &A 237 357 480 723 969 m 248 375 503 759 1,014 3»fl« 260 393 530 794 1,064 3^16 272 411 552 835 1,113 4tf 6 285 430 575 871 1,167 4?ie 297 448 601 907 1,216 4#6 309 467 628 947 1,266 4?16 322 485 651 987 1,320 4%6 334 507 678 1,023 1,373 4Hie 347 525 705 1,064 1,427 4^6 361 543 731 1,104 1,481 4^16 374 566 759 1,145 1,534 5Vi 6 387 583 785 1,189 1,589 5?'l6 401 606 812 1,230 1,647 5M 415 628 844 1,270 1,706 5^ 429 646 871 1,315 1,764 5}^ 443 669 898 1,360 1,818 5% 458 691 929 1,400 1,876 5% 471 714 956 1,445 1,939 5Vs 485 736 987 1,490 1,997 6 498 754 1,014 1,534 2,056 6H 516 776 1,046 1,580 2,118 m 530 799 1,077 1,625 2,181 &A 543 826 1,104 1,674 2,240 VA 561 848 1,136 1,719 2,303 m 575 871 1,167 1,768 2,365 QH 588 893 1,198 1,813 2,433 m» 606 916 1,230 1,863 2,494 6»%6 619 938 1,261 1,912 2,558 7H« 637 965 1,293 1,957 2,626 7?'l6 651 987 1,329 2,006 2,693 7%6 669 1,010 1,360 2,060 2,756 7 7 /l6 682 1,037 1,391 2,105 2,823 7?i6 700 1,059 1,423 2,159 2,890 7Hie 718 1,086 1,459 2,208 2,958 71?i6 732 1,109 1,490 2,258 3,030 7»%6 750 1,136 1,526 2,311 3,097 m» 768 1,162 1,557 2,361 3,164 8?i6 781 1,185 1,598 2,415 3,236 8Ji 799 1,212 1,629 2,464 3,303 8^ 817 1,239 1,665 2,518 3,375 8K2 835 1,261 1,697 2,572 3,447 SVs 853 1,288 1,732 2,626 3,519 m 866 1,315 1,768 2,680 3,591 w 884 1,342 1,804 2,733 3,667 9 902 1,369 1,840 2,787 3,739 9M 920 1,396 1,876 2,841 3,811 m 938 1,423 1,912 2,895 3,887 Ws 956 1,450 1,948 2,953 3,959 m 974 1,477 1,984 3,007 4,035 m 992 1,504 2,024 3,066 4,111 m 1,010 1,531 2,060 3,119 4,188 mu 1,028 1,557 2,096 3,178 4,264 9»%a 1,046 1,589 2,132 3,236 4,340 10V.6 1,064 1,616 2,172 3,290 4,416 10^16 1,082 1,643 2,208 3,348 4,493 10%6 1,104 1,670 2,249 3,407 4,574 ioy,6 1,122 1,701 2,289 3,465 4,650 lOfiti 1,140 1,728 2,325 3,523 4,731 ioiy.6 1,158 1,759 2,365 3,586 4,807 101?'l6 1,176 1,786 2,401 3,645 4,888 io'y 16 1,198 1,818 2,442 3,703 4,969 lHie 1,216 1,845 2,482 3,761 5,049 119ia 1,234 1,876 2,522 3,824 5,130 nx 1,252 1,903 2,563 3,882 5,211 n*A 1,275 1,934 2,603 3,945 5,292 n l A 1,293 1,961 2,644 4,008 5,377 n% 1,315 1,993 2,684 4,066 5,458 u% 1,333 2,024 2,724 4,129 5,539 WA 1,351 2,051 2,760 4,192 5,624 12 1,373 2,083 2,805 4,255 5,709 CIRC. 312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 21 point of discharge and the supply water surface. Such figures are useful only for making a rough check of the operation of a pumping plant. For pumps such as the deep well turbines installed in such a way that their suction lines are inaccessible, but whose discharge lines may be tapped, measurement is made of the distance in feet from the ground surface to the surface of the supply water. To this is added the vertical distance from the ground surface to the center of the discharge pipe at its highest point, if the discharge is close to the pump. If it is not, a pressure gage must be tapped into the discharge line and its reading in feet must be added to the vertical distance in feet between the center of the gage and the ground surface, plus the vertical distance in feet between the ground surface and the supply- water surface. Manufacturers of deep w T ell turbines consider the part of the dis- charge column pipe below ground as a portion of the pump, making the pumping-lift readings as obtained above acceptable. The measurement of the vertical distance between the ground and water-supply surface may be obtained only through the use of a sounding line (fig. 9). This may be an electrically insulated wire with an exposed end let down into the well so that it will ground in the water, making a complete circuit with a bell ringer in it. Measure- ment of the length of line will give the depth to water. On the other hand, it may be an air line of pipe of known length run down into the well with the pump. Air is forced into this line and the maximum pressure obtainable is recorded in pounds or feet on a gage at the sur- face (fig. 9). Some of these gages read the number of feet to water direct. Those reading in pounds must be corrected to feet by multi- plying the reading by 2.31 (1 pound equals 2.31 cubic feet of water). This number of feet indicates the submersion of the end of the air line. Subtracting the submersion in feet from the total length of the line in feet gives the distance to water. Example : A 120-foot air line in a well being pumped requires 13 pounds air pressure to force the water out of the line. The pressure goes no higher than 13 pounds, because the air escapes at the bottom as fast as more is added when this point is reached. Thirteen pounds equals 13 X 2.31 feet of water or 30.03 feet of water (call it 30 feet), the submersion of the end of the air line. Therefore, the depth to water is 120 feet less 30 feet, or 90 feet. A direct reading pressure gage scaled in feet would have indicated 90 feet immediately under these conditions. All pump installations should be designed to permit measurements of the depth of water. Special precautions must be taken to make this possible in placing deep well pumps. Ground wire to purnpy Telephone mogneto Air sounding line @" pipe) Pumping yvoter /'eye I L "Sore end on //he ferfbrvted ** cosing Fig. 9. — Diagram of air-lift pump in well, showing two methods of sound- ing depths in wells. \4/r iine from compressor enters pump column of bottom. ClEG. 312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 23 The power input may be measured readily in the field only for electrically driven units. Although the power companies will be glad to assist in this measurement, the owner can determine it for himself after ascertaining the number of watts registered by the electric meter in his pumping plant for each revolution of the aluminum disk (fig. 10). He should be sure that the figure furnished in watts includes any special set-up constants for the installation. After this WATT HOUR METER 'Count rero/L/f/ons of f/v's cf/^k Fig. 10. — Electric-meter indicating disk. In making a pumping-plant test, the revolutions of this disk are to be counted. figure, commonly known as a disk constant, is obtained, the number of revolutions of the aluminum disk should be counted for several minutes and the total divided by the exact number of minutes counted. This figure should be multiplied by the constant obtained from the power company, and the result multiplied by 60 and divided by 746. The final figure is the horsepower being supplied to the motor. With the completion of this step, the over-all, or plant efficiency, may be computed as follows : Multiply the discharge in gallons per minute by 24 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION the weight of a gallon of water (8.33 pounds) and multiply this by the distance the water is lifted, in feet. Then divide the result by 33,000. The result is horsepower represented by water pumped. The plant efficiency is the important item to the user, since it tells how well the whole unit is working. From the buyer's viewpoint the seller should specify the plant efficiency when indicating the char- acteristic of operation. The over-all or plant efficiency is the water horsepower output divided by the electrical horsepower input, with the result multiplied by 100. Checking the speed of an electrically driven unit will occasionally demonstrate a faulty motor, but this condition is seldom found. Plants not electrically driven may be tested to determine the discharge, the head pumped against, and the speed of rotation. The last named requires the use of a speed counter, which most pump-installation men have in their equipment. If the pump is up to the speed specified, it should deliver the quantity of water indicated by the seller for the head being pumped against. Tests of an irrigation pumping plant should be made occasionally throughout its life so that the necessary adjustments may be made to maintain a satisfactory efficiency. DISCUSSION OF FIELD CONDITIONS Operators of irrigation pumping equipment have always felt somewhat dissatisfied with the cost of operation and the performance of their pumping equipment. In order to determine the sources of this dissatisfaction, investigations were conducted in the field during parts of 1924, 1925, and 1926. These consisted of field tests of many pumping plants, conducted in as thorough a manner as possible. All measurements were checked by several readings, which were averaged. All gages were checked for accuracy and in several instances electric watt-hour meters were tested by the power companies to make certain of their accuracy. These instruments were seldom found more than 1 per cent in error by the company tester. Wherever possible, weirs were used in making readings of discharge and when their use was impossible, every effort was made to insure accuracy by checking several methods against each other. Soundings to water in the wells were made, where possible, with an insulated wire which completed an electric circuit with a bell ringer in it when contact was made with the water. Occasionally, an air line of known length was avail- able and sounding was made with it, checking with the electric sounder wherever this could be done. Tables 2 and 3 indicate in CIRC, 312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 25 general the results of these tests, showing the average operating con- ditions for the three types of pumps tested. These figures might vary a few points either way, were they for another set of pumping plants, but they represent a fair cross-section of the irrigation pumping plants supplied by wells. They are probably typical of the whole state, since they were taken in a number of areas. TABLE 2 Eesults of Field Tests of Irrigation Pumping Plants Type Average head Average discharge Plant efficiency Plants tested Centrifugal Deep well turbine feet 49.9 124.0 81.6 gals, per minute 3,685.5 958.5 1,066.5 per cent 49.8 40.5 44.5 33 31 27 TABLE 3 Approximate Characteristics of Air Lift, Plunger, and Eotary Displacement Pumps Type Average discharge Average efficiency Air lift gallons per minute 225 382.5 225 per cent 23 60 Rotary displacement 50-60 It will be noted in the tables above that the average discharge of the centrifugals is considerably higher than for the other two types tested. This is due to the inclusion of several 10 and 20-second-foot units among the centrifugal-pump tests. These plants were about twenty years old, and their efficiencies were still considerably above the average for the type. They were much older than any of the screw pumps or deep well turbines tested. The centrifugal pumps of capacity corresponding to the other two types showed about the average efficiency of their type. In many cases the small centrifugals fell considerably below the average for the type. Plant efficiencies for the three types ranged from 15.2 per cent in several cases to 70 per cent in one case. The discouraging feature of the tests was that so many plants should be operating at one-half or less than one-half of the average efficiencies for the type. It is apparent that the average efficiencies 26 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION Fig. 11. — Typical deep-well pumping plant in house. CIRC. 312] OPERATION OF SMALL IRRIGATION PUMPING PLANTS 27 are not ideal, since they represent conditions of power waste amount- ing to over one-half that furnished. Were the lowest efficiencies up to the average for that particular type, the owner's power bill would, in some cases, be less than half what it is. Such conditions are largely chargeable to failure on the part of the owner to keep his equipment in good running order. There is little excuse for centrifugals to go far below their normal efficiency because they are accessible at all times and repairs are simple. The other two types, as has been mentioned, are more difficult to inspect and to repair. However, efficiencies as low as some of those found indicate that occasional tests will pay for themselves by calling forth the necessary repairs. The burden of fault does not rest entirely upon the owners of these plants showing low efficiencies, because the manufacturing and sales agencies have been responsible for some of this trouble. Their equipment has not always stood up in service as it should, because makeshifts in construction have been employed. Part of these make- shifts are the result of efforts on the part of manufacturers to attain a low sale price for their products in order to meet competition. Such practice is not countenanced by the more reputable manufac- turers, but the individual buyers of pumping equipment often mistake poorly made machines for bargains. The electric motor or the electric distribution system may be responsible for low efficiencies of operation in pumping plants, but this is the exception rather than the rule. When an operator has become suspicious of his electrical equipment, he should first make sure that the fault is not in the pump. SUMMARY Centrifugal pumps are simple and are easily cared for. They are located on ground-surface foundations or in open pits, as a rule. They are best fitted to operate where the water supply is readily approach- able, as in the case of surface waters or shallow underground supplies. When correctly installed, their efficiency should be good. Deep well turbine pumps are much like the centrifugals in per- formance, but they are not so easily inspected and kept in repair. They may be used to pump water from almost any depth, and if inspected and repaired occasionally, should show good operating efficiency. Screw-type pumps lend themselves to a variety of applications including both long and short lifts. Its characteristic is its large capacity. In the deep well units, it is hampered in its performance 28 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION by the fact that it is not easily inspected. Its efficiency is good if it is inspected and repaired occasionally. The air-lift pump has as its chief asset its simplicity and lack of wearing- parts, thus making it suitable for use in developing wells. Its application to irrigation is limited to special conditions because of its low efficiency. Because they are limited in capacity, the plunger pumps are used generally in irrigating comparatively small tracts. There are many areas with deep water supplies of limited capacity served largely by this type of pump. Plunger pumps are also limited in use by the fact that abrasive materials in the water supply soon cut them out, destroying their otherwise very good efficiency. The rotary displacement pump is very similar to the plunger pump in its application to irrigation. It has the same limitations as the latter and also it can be used only where there are surface or shallow underground waters. To be satisfactory, plant efficiencies should not be below 50 per cent. A large number of plants in the field operate considerably below this figure. Many are doing so because their owners or operators have failed to inspect and repair them as they should. Some pumps are so poorly made that they cannot maintain nor even attain 50 per cent plant efficiency. These units may be eliminated through proper selection by the bivyers. New plants should be placed only in a developed well and should be tested for operating efficiency. Check tests should be made throughout the life of all plants. STATION PUBLICATIONS AVAILABLE FOR FREE DISTRIBUTION BULLETINS No. 253. Irrigation and Soil Conditions in the Sierra Nevada Foothills, California. 262. Citrus Diseases of Florida and Cuba Compared with those of California. 263. Size Grades for Ripe Olives. 268. Growing and Grafting Olive Seedlings. 273. Preliminary Report on Kearney Vine- yard Experimental Drain, Fresno County, California. 276. The Pomegranate. 277. Sudan Grass. 278. Grain Sorghums. 279. Irrigation of Rice in California. 283. The Olive Insects of California. 294. Bean Culture in California. 304. A Study of the Effects of Freezes on Citrus in California. 810. Plum Pollination. 312. Mariout Barley. 813. Pruning Young Deciduous Fruit Trees. 819. Caprifigs and Caprification. 324. Storage of Perishable Fruit at Freez ing Temperatures. 325. Rice Irrigation Measurements and Experiments in Sacramento Valley, 1914-1919. 328. Prune Growing in California. 331. Phylloxera-Resistant Stocks. 835. Cocoanut Meal as a Feed for Dairy Cows and Other Livestock. 339. The Relative Cost of Making Logs from Small and Large Timber. 840. Control of the Pocket Gopher in California. 343. Cheese Pests and Their Control. 344. Cold Storage as an Aid to the Mar- keting of Plums. 346. Almond Pollination. 347. The Control of Red Spiders in Decid uous Orchards. 348. Pruning Young Olive Trees. 349. A Study of Sidedraft and Tractor Hitches. 350. Agriculture in Cut-over Redwood Lands. 353. Bovine Infectious Abortion. 354. Results of Rice Experiments in 1922. 357. A Self-mixing Dusting Machine for Applying Dry Insecticides and Fungicides. 358. Black Measles, Water Berries, and Related Vine Troubles. 361. Preliminary Yield Tables for Second Growth Redwood. 362. Dust and the Tractor Engine. 363. The Pruning of Citrus Trees in Cali- fornia. 364. Fungicidal Dusts for the Control of Bunt. 365. Avocado Culture in California. 366. Turkish Tobacco Culture, Curing and Marketing. 367. Methods of Harvesting and Irrigation in Relation of Mouldy Walnuts. 368. Bacterial Decomposition of Olives dur- ing Pickling. 369. Comparison of Woods for Butter Boxes. 370. Browning of Yellow Newtown Apples. 371. The Relative Cost of Yarding Small and Large Timber. 373. Pear Pollination. 374. A Survey of Orchard Practices in the Citrus Industry of Southern Cali- fornia. 375. Results of Rice Experiments at Cor- tena, 1923. 376. Sun-Drying and Dehydration of Wal nuts. 377. The Cold Storage of Pears. 379. Walnut Culture in California. No. 380. 382. 385. 386. 387. 388. 389. 390. 391. 392. 393. 394. 395. 396. 397. 398. 399. 400. 401. 402. 404. 405. 406. 407. 408. 409. 410. 411. 412. 414. 415. 416. 417. 418. 419. 420. 421. 422. 423. 424. 425. 426. 427. 428. 429. Growth of Eucalyptus in California Plantations. Pumping for Drainage in the San Joaquin Valley, California. Pollination of the Sweet Cherry. Pruning Bearing Deciduous Fruit Trees. Fig Smut. The Principles and Practice of Sun- drying Fruit. Berseem or Egyptian Clover. Harvesting and Packing Grapes in California. Machines for Coating Seed Wheat with Copper Carbonate Dust. Fruit Juice Concentrates. Crop Sequences at Davis. Cereal Hay Production in California. Feeding Trials with Cereal Hay. Bark Diseases of Citrus Trees. The Mat Bean (Phaseolus aeon it if o lius). Manufacture of Roquefort Type Cheese from Goat's Milk. Orchard Heating in California. The Blackberry Mite, the Cause of Redberry Disease of the Himalaya Blackberry, and its Control. The Utilization of Surplus Plums. Cost of Work Horses on California Farms. The Codling Moth in Walnuts. The Dehydration of Prunes. Citrus Culture in Central California. Stationary Spray Plants in California. Yield, Stand and Volume Tables for White Fir in the California Pine Region. Alternaria Rot of Lemons. The Digestibility of Certain Fruit By- products as Determined for Rumi- nants. Factors Affecting the Quality of Fresh Asparagus after it is Harvested. Paradichlorobenzene as a Soil Fumi- gant. A Study of the Relative Values of Cer- tain Root Crops and Salmon Oil as Sources of Vitamin A for Poultry. Planting and Thinning Distances for Deciduous Fruit Trees. The Tractor on California Farms. Culture of the Oriental Persimmon in California. Poultry Feeding: Principles and Practice. A Study of Various Rations for Finishing Range Calves as Baby Beeves. Economic Aspects of the Cantaloupe Industry. Rice and Rice By-products as Feeds for Fattening Swine. Beef Cattle Feeding Trials, 1921-24. Cost of Producing Almonds in Cali- fornia ; a Progress Report. Apricots (Series on California Crops and Prices). The Relation of Rate of Maturity to Egg Production. Apple Growing in California. Apple Pollination Studies in Cali- fornia. The Value of Orange Pulp for Milk Production. The Relation of Maturity of Cali- fornia Plums to Shipping and Dessert Quality. Economic Status of the Grape Industry. No. 87. 117. 127. 129. 136. 144. 157. 164. 166. 170. 173. 178. 179. 202. 203. 209. 212. 215. 217. 230. 231. 232. 234. 238. 239. 240. 241. 243. 244. 245. 248. 249. 250. 252. 253. 254. 255. 256. 257. 258. Alfalfa. The Selection and Cost of a Small Pumping Plant. House Fumigation. The Control of Citrus Insects. Melilotus indica as a Green-Manure Crop for California. Oidium or Powdery Mildew of the Vine. Control of the Pear Scab. Small Fruit Culture in California. The County Farm Bureau. Fertilizing California Soils for the 1918 Crop. The Construction of the Wood-Hoop Silo. The Packing of Apples in California. Factors of Importance in Producing Milk of Low Bacterial Count. County Organizations for Rural Fire Control. Peat as a Manure Substitute. The Function of the Farm Bureau. Salvaging Rain-Damaged Prunes. Feeding Dairy Cows in California. Methods for Marketing Vegetables in California. Testing Milk, Cream, and Skim Milk for Butterfat. The Home Vineyard. Harvesting and Handling California Cherries for Eastern Shipment. Winter Injury to Young Walnut Trees during 1921-22. The Apricot in California. Harvesting and Handling Apricots and Plums for Eastern Shipment. Harvesting and Handling Pears for Eastern Shipment. Harvesting and Handling Peaches for Eastern Shipment. Marmalade Juice and Jelly Juice from Citrus Fruits. Central Wire Bracing for Fruit Trees. Vine Pruning Systems. Some Common Errors in Vine Prun- ing and Their Remedies. Replacing Missing Vines. Measurement of Irrigation Water on the Farm. Supports for Vines. Vineyard Plans. The Use of Artificial Light to Increase CIRCULARS No. 259. 261. 262. 263. 264. Winter Egg Production. Leguminous Plants as Organic Fertil- izer in California Agriculture. The Control of Wild Morning Glory. The Small-Seeded Horse Bean. Thinning Deciduous Fruits. 265. 266. 267. 269. 270. 272. 273. 276. 277. 278. 279. 281. 282. 283. 284. 285. 286. 287. 288. 289. 290. 291. 292. 293. 294. 295. 296. 298. 300. 301. 302. 303. 304. 305. 306. 307. 308. 309. Pear By-products. Sewing Grain Sacks. Cabbage Growing in California. Tomato Production in California. Preliminary Essentials to Bovine Tuberculosis Control. Plant Disease and Pest Control. Analyzing the Citrus Orchard by Means of Simple Tree Records. The Tendency of Tractors to Rise in Front; Causes and Remedies. An Orchard Brush Burner. A Farm Septic Tank. California Farm Tenancy and Methods of Leasing. Saving the Gophered Citrus Tree. Home Canning. Head, Cane, and Cordon Pruning of Vines. Olive Pickling in Mediterranean Coun- tries. The Preparation and Refining of Olive Oil in Southern Europe. The Results of a Survey to Determine the Cost of Producing Beef in Cali- fornia. Prevention of Insect Attack on Stored Grain. Fertilizing Citrus Trees in California. The Almond in California. Sweet Potato Production in California. Milk Houses for California Dairies. Potato Production in California. Phylloxera Resistant Vineyards. Oak Fungus in Orchard Trees. The Tangier Pea. Blackhead and Other Causes of Loss of Turkeys in California. Alkali Soils. The Basis of Grape Standardization. Propagation of Deciduous Fruits. The Growing and Handling of Head Lettuce in California. Control of the California Ground Squirrel. The Possibilities and Limitations of Cooperative Marketing. Coccidiosis of Chickens. Buckeye Poisoning of the Honey Bee. The Sugar Beet in California. A Promising Remedy for Black Measles of the Vine. Drainage on the Farm. Liming the Soil. A General Purpose Soil Auger and its Use on the Farm. American Foulbrood and its Control. Cantaloupe Production in California. Fruit Tree and Orchard Judging. The publications listed above may be had by addressing College of Agriculture, University of California, Berkeley, California. 12m-3,'28