Division of Agricult u r a I Sciences 
 
 
 
 L 1 F O R N 1 A 
 
 U N 1 V E R S 1 
 
 T Y ° F c A 
 
 PLAI G 
 
 CULTUR 
 
 Experiment 
 Extension Service 
 
 11 J •I'll 
 
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 ?V M4T1NG 
 
 3 
 
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 THIS CIRCULAR TELLS . . . 
 
 • how plants, soil, and water depend on each 
 other 
 
 • why contour irrigation is practical, even on 
 steep slopes 
 
 • how to lay out a contour planting, particu- 
 larly one designed for a small acreage. 
 
 BUT 
 
 It does not attempt to furnish complete informa- 
 tion on laying out contour plantings under diffi- 
 cult conditions. University of California Farm 
 Advisors can direct you to a competent engi- 
 neer for advice on such problems. 
 
 A CONTOUR GRADE . . . 
 
 ... is the per cent of slope of a contour 
 irrigation furrow. Grades vary, for reasons 
 described in this circular, from half a foot to 
 three feet per hundred feet of length. 
 
 MODERATE-TO-STEEP SLOPES . . . 
 
 . . . are considered in this circular as 
 slopes too steep to permit successful use of 
 ordinary irrigation methods, such as borders, 
 basins, and straight furrows. 
 
 THIS PUBLICATION . . . 
 
 . . . replaces Agricultural Extension Ser- 
 vice Circular 16— "Irrigation of Orchards by 
 Contour Furrows," by M. R. Huberty and J. B. 
 Brown. (1928, rep. 1932) 
 
?#» 
 
 M 
 
 £PmtoU^ 
 
 enables you to 
 
 use steep slopes otherwise unsuitable for irrigation 
 
 avoid serious soil erosion 
 
 use irrigation water more efficiently 
 
 Most of California's good flat lands have been put to use. Intensive agriculture 
 is now literally "taking to the hills," and contour planting is providing an effective 
 way of using this hilly land. 
 
 Contour planting and irrigation is widely used by southern California citrus and 
 avocado growers. Outstanding examples of such plantings can be seen in Ventura 
 County, where the system has long been used by citrus growers. The practice is also 
 employed to a limited extent throughout California by growers of bushberries, de- 
 ciduous fruit, and vegetable crops such as cantaloupes and tomatoes. Practically all 
 strawberries are planted on a slightly modified contour system. 
 
 Planting and irrigation on the contour grade could be applied profitably to other 
 hilly or sloping areas of California, with almost any kind of crop. 
 
 Contour planting has three advantages: 
 
 1 — It makes possible the use of steep slopes which could not be irrigated properly 
 with any other method except sprinklers. Irrigating on the contour allows water to 
 flow slowly in furrows that cross the slope on gentle grades. 
 
 2 — Since the furrow grade is calculated according to the texture of the soil, the 
 danger of furrow erosion is minimized. 
 
 3 — Since irrigation water runs along gentle furrow grades, its percolation into 
 the soil is much greater than that of shallower water running in steep, straight 
 furrows. Water use is therefore more efficient. 
 
 THE AUTHOR: Lloyd N. Brown is an Extension Soils Specialist in the University of California 
 Agricultural Extension Service. 
 
 SEPTEMBER, 1954 
 
The Fundamentals 
 Of irrigation 
 
 Before attempting any kind of irriga- 
 tion it is important to know certain 
 fundamentals. This is particularly true 
 for the difficult practice of irrigating 
 steep slopes. 
 
 Water is stored 
 in the soil 
 
 Soil acts as a reservoir to store irriga- 
 tion water. Therefore the soil occupied 
 by the plant roots should be filled to field 
 capacity. Plant roots take from one to 
 several weeks to deplete the stored water 
 to the permanent wilting percentage. 
 
 Soils vary greatly in the amount of 
 water they will hold at field capacity. 
 When soil particles are small there are 
 more water-holding surfaces per unit of 
 volume than when the particles are 
 larger. Fine soil will therefore hold more 
 water than coarse. 
 
 For example, loam holds about twice 
 as much water as sand; clay holds about 
 twice as much as loam. If we call the 
 capacity of sand 1, loam will be 2 and 
 clay 4. In terms of weight, sand holds 
 
 The following are terms frequently 
 used in this circular: 
 
 FIELD CAPACITY: The quantity of wa- 
 ter that soil will hold a day or two after 
 irrigation, when the water has freely 
 moved downward and horizontally. 
 
 PERMANENT WILTING PERCENTAGE: 
 The point at which soil has insufficient 
 moisture to prevent plants from wilting. 
 
 ACRE-INCH: The amount of water that 
 will cover one acre one inch deep- 
 equivalent to a one-inch rainfall. 
 
 PER CENT SLOPE: The fall or rise of 
 land in feet per hundred feet of horizon- 
 tal distance. 
 
 about 7% of its dry weight in water, 
 loam about 14%, and clay about 28%. 
 The moisture in the soil which can be 
 considered readily available to the plants 
 is the difference between the field capac- 
 ity and the permanent wilting percentage 
 (PWP). The PWP is usually about half 
 the field capacity. Occasionally, however, 
 the PWP may be as much as % of the 
 field capacity, in which case more fre- 
 quent irrigations are needed. Some red 
 soils of the Sierra Nevada foothills have 
 this narrow range between PWP and 
 field capacity. 
 
 Irrigation frequency 
 depends on soil type 
 
 Because of these different water-hold- 
 ing capacities, you should water sands 
 about twice as often as loams and loams 
 twice as often as clays. This will keep 
 water available to the roots at all times. 
 Applying this principle to a field or 
 orchard, you should plan to start irri- 
 gating soon enough so that when several 
 days are required for the complete job 
 the last plants to be irrigated will receive 
 water before they wilt. 
 
 Some plants, such as corn and lettuce, 
 when young have sparse root systems 
 which do not occupy the whole soil mass. 
 Therefore frequent, light irrigations are 
 necessary in order to maintain a supply 
 of moisture immediately adjacent to the 
 roots. 
 
 When to start 
 irrigating 
 
 Timing the first irrigation depends on 
 how much moisture has been supplied by 
 winter and spring rains. A light winter 
 rainfall which fails to wet the entire root 
 zone will make earlier irrigation neces- 
 sary. 
 
 [4] 
 
In the case of annual crops, the soil 
 should usually be irrigated before plant- 
 ing. 
 
 Orchards follow a pattern in their use 
 of water. In deciduous orchards, use is 
 low in spring, reaches a peak in summer, 
 and drops in fall. Citrus, being an ever- 
 green, uses more water in winter than 
 deciduous trees. Both types reach peak 
 use in July and August. 
 
 Irrigation water penetrates the 
 soil a definite distance. The area 
 penetrated — downward and horizontally 
 — is then at field capacity, and the mois- 
 ture content of adjacent soil remains un- 
 changed. 
 
 An ideal irrigation should wet all of 
 the soil occupied by the plant roots; 
 hence furrows should be spaced close 
 enough to wet all the soil. 
 
 Don't over-irrigate. Over-irrigation 
 wastes water and may harm plants. 
 
 Frequently soils which are contour- 
 planted are of limited depth, underlain 
 by bedrock, hardpan, or claypan. Over- 
 irrigation may cause water to collect on 
 
 INCHES OF WATER USED 
 
 in Orchards 
 
 Month Deciduous Citrus 
 
 March 1 
 
 April 1 2 
 
 May 3 2 
 
 June 5 3 
 
 July 6 4 
 
 August 6 4 
 
 September 3 3 
 
 October 1 2 
 
 November 1 
 
 these impervious layers, thus creating 
 moisture conditions in excess of field 
 capacity. 
 
 Root-rot in avocado groves and gum- 
 mosis in citrus trees may be caused by 
 such excess water. 
 
 When irrigation water contains large 
 amounts of soluble salts, however, some 
 over-irrigation is desirable. Repeated use 
 of such water can cause an accumulation 
 of salt harmful to plants. A heavy irriga- 
 tion is then necessary to carry the salts 
 below the root zone. 
 
 SOIL TERMS USED IN THIS CIRCULAR 
 
 Fine 
 
 Medium 
 
 Coarse — 
 
 mm 
 
 
 EXAMPLE 
 
 Clay 
 
 — Loam 
 
 — Sand 
 
 [5] 
 
Is Your land Suited 
 To Contour Planting? 
 
 Generally speaking, the best way to 
 determine the suitability of land for con- 
 tour planting is to consult local farmers 
 who have used the method. The following 
 characteristics are particularly desirable 
 in land that is to be contour-planted : 
 
 Soil depth must 
 be adequate 
 
 Soil should be deep enough so that 
 leveling operations will not impair its 
 ability to grow a crop. On sloping land 
 the soil is usually shallow: for example, 
 on rolling terrace areas the subsoil is 
 claypan or hardpan, and on hills the soil 
 is commonly underlain by bedrock. If re- 
 quired leveling operations are very exten- 
 tive, the site is probably not practical for 
 contour planting. 
 
 EROSION LIKE THIS is the result of using too 
 steep a furrow grade. 
 
 Medium textures 
 are preferable 
 
 Soil should preferably be of a me- 
 dium texture. Soils such as loams and 
 clay-loams are usually easier to handle 
 and are most productive. Fine soils crack 
 badly on drying and water often breaks 
 out of the furrows. Sandy soils are liable 
 to present a serious erosion problem 
 when furrows break during irrigation or 
 as a result of rain. 
 
 Is slope suited 
 to operation? 
 
 Slope of the land should be consid- 
 ered in choosing a site, since contour 
 irrigation and other orchard operations 
 become increasingly difficult as the slope 
 increases. In practice the deciding factor 
 as to whether a slope is usable is whether 
 orchard operations can be performed 
 economically. 
 
 Flatter slopes can be irrigated on the 
 natural surface. Cultivation and furrow- 
 ing on intermediate slopes tend to build 
 up moderate terraces. On slopes steeper 
 than 25 or 30% it is usually advisable 
 to build bench terraces (see page 19). 
 
 For field crops, vegetable crops, and 
 strawberries the upper limit of slope is 8 
 to 10%. Steeper inclines can be irrigated, 
 but all cultural practices become increas- 
 ingly difficult. 
 
 Don't overlook need 
 for drainage 
 
 A practical means for draining off 
 excess water must be at hand. This is im- 
 portant in contour planting to avoid ero- 
 sion. Excess water from rainfall or irri- 
 gation can be removed over grass water- 
 ways in swales or through concrete pipes 
 with suitable inlets. 
 
Designing a Good 
 furrow System 
 
 The ideal furrow system would wet all 
 of the soil occupied by the crop roots, 
 with a minmum of tail waste, with avoid- 
 ance of waterlogging, and with little or 
 no soil erosion. 
 
 To design such a system, two principal 
 factors must be taken into account: grade 
 of furrow and length of furrow. 
 
 Two variables determine 
 the furrow grade 
 
 The diagram below shows how two va- 
 riable elements — soil texture and steep- 
 ness of the land — affect the choice of the 
 most efficient furrow grade to use in a 
 particular situation. Results obtained 
 will be approximations only. 
 
 SLOPE 
 
 4% 
 
 3% 
 
 2% 
 
 
 Coo'*-' 6 
 
 l°/0 
 
 5% 10% 15% 20% 25% 
 
 YOU CAN MAKE a rough estimate of the furrow grade best suited to your land by using this 
 diagram. For example: You have a piece of land with a 15% average slope; the soil is medium- 
 textured; you want to plant and irrigate on the contour. First, find 15% on the bottom (slope) 
 scale; then move up to about the middle of the green area; make a pencil dot at that point; 
 now, at left, read the per cent of grade for that point. In this case it is about 2.2%. Similarly, 
 for a fine-textured soil on a 20% slope, the grade would be about 2.8%. A coarse soil on the 
 same slope would take a furrow grade of about 2.2%. 
 
 [7] 
 
LEVEL 
 
 mmm 
 
 AS SLOPES become steeper, the lower side of 
 the furrow is more likely to be over-topped by 
 the water in the furrow. Diagram above shows 
 why the practical limit of slope for furrow irri- 
 gation is about 20%. 
 
 Soil texture: Coarse soils erode read- 
 ily, so grades should be kept fairly flat. 
 Medium soils resist erosion better; there- 
 fore intermediate furrow grades can be 
 used. Fine soils are most resistant to 
 erosion; consequently furrow grades 
 may be steeper. Gravelly or rocky soils 
 are also suitable for steeper furrow 
 grades, because as water flows down the 
 furrow it exposes the gravel and rocks on 
 the furrow bottom. This material pro- 
 tects the soil underneath from erosion. 
 
 Steepness of land: The shaded part 
 of the diagram on page 7 slants upward 
 from left to right, indicating that steeper 
 slopes require steeper furrow grades. The 
 reason why steeper grades are necessary 
 
 can be seen in the diagram at left, which 
 shows how irrigation water is more apt 
 to overtop a furrow as land becomes 
 steeper. 
 
 Steeper furrow grades compensate for 
 steeper slopes by increasing the velocity 
 of the irrigation water and thereby de- 
 creasing its depth. 
 
 Occasionally it is impractical to grade 
 land smooth, with the result that it is 
 difficult to lay out furrows on uniform 
 grades. Under these conditions care 
 should be taken to make the flatter parts 
 of the furrow steep enough to carry the 
 water. 
 
 Obviously, the furrow grade should 
 not be increased to the point where soil 
 erosion will be excessive. 
 
 Match length of 
 furrow to soil 
 
 In designing a furrow system it is im- 
 portant to consider the susceptibility of 
 the soil to erosion. Long furrows can be 
 used on fine soils but short furrows are 
 necessary on coarse soils because water 
 penetrates coarse soil more easily than 
 fine soil. Fine soil is therefore usually 
 cheaper to irrigate because fewer pipe- 
 lines are required. (See table below.) 
 
 Since water enters coarse soil readily, 
 shorter furrows and extra pipelines are 
 required to avoid losing water through 
 deep penetration and to avoid applying 
 so much as to build up a temporary 
 water table on the subsoil. The expense 
 of extra pipelines may make irrigation of 
 coarse soils on steep slopes uneconomical. 
 
 TABLE BELOW shows suggested furrow lengths 
 
 and irrigation times for different soil textures. 
 
 Duration of irrigation and length of furrow 
 
 vary directly with the fineness of the soil. 
 
 Length of Furrow 
 
 Soil 
 
 Duration of Irrigation 
 
 200-400 ft. 
 400-600 ft. 
 600-800 ft. 
 
 Coarse 
 
 Medium 
 
 Fine 
 
 2- 6 hrs. 
 
 6-12 hrs. 
 
 12-24 hrs. 
 
 [8] 
 
The Next Step . . . 
 CHooshg a Planting Layout 
 
 After you have estimated the most de- 
 sirable grade and length for irrigation 
 furrows, decide on a system of planting. 
 
 Contour plantings vary greatly in de- 
 tail, since each area presents its own 
 problems and each owner has his own 
 ideas. Two principal systems will be il- 
 lustrated in this circular; they are the 
 most widely used in laying out contour 
 plantings. 
 
 Contour-planting 
 terminology 
 
 Before studying planting systems you 
 should become familiar with contour- 
 
 planting terms. These are illustrated in 
 the diagram below, which shows an or- 
 chard laid out with contour rows and 
 straight up-and-down (cross) rows. Con- 
 tour rows begin just to the right of the 
 pipeline. Arrows indicate the direction of 
 water flow. Each line may represent 
 several furrows. 
 
 Rows 1 and 2 separate noticeably at 
 the right of the sketch. To fill this space 
 a fill row (B) is inserted as shown. Like- 
 wise a spike row (C) is put between 
 Rows 2 and 3. The row that is pinched 
 out between Rows 3 and 4 becomes a stub 
 row (A). 
 
 Terms Used in Contour Planting 
 
 
 2 ip^o^ 
 
 ^o — o- 
 
 a—.. 
 
 £>_ 
 
 C^IZ^^O^q 
 
 Q-— 
 
 0--0- 
 
 HEAVY LINES indicate water flow from pipeline at left. Lines may represent several furrows. 
 
 Trees connected by dotted lines form contour grade rows, while trees up and down the slope 
 
 form cross rows. A stub row is shown at A; a fill row at B; and a spike row at C. 
 
 [9] 
 
There Are Two Principal 
 
 ' 
 
 O /^-^ XX .XX' 
 
 / / 
 
 
 G---0- 
 
 a 
 
 XX. 
 
 xx 
 
 
 or---- - ^ a ~\_ ,.e 
 
 Contour Li 
 
 G --0--G--0~--0--0 
 
 ^ '**' J"*"*"!, """* — -^ Contour Line . — •• — ' 
 
 Above and at right, the two planting systems applied to the same topography. 
 
 SySTCAf l-Htt Cross tows 
 
 SOUTHERN CALIFORNIA citrus orchard is a 
 
 variation of System I. SYSTEM ,_ Uniform spacing of trees a|ong a 
 
 contour grade without regard to alignment in 
 other direction. 
 
 The main advantage of this system is that it 
 is well suited to steep, irregular topography. It 
 usually results in more trees per acre than 
 
 " v * . ^ • System II. 
 
 Up-and-down-hill cultivation cannot be prac- 
 ticed, because there are no crossrows. This is 
 probably an advantage, since such cultivation 
 tends to leave mounds around the trees, thus 
 making irrigation more difficult. 
 
 A disadvantage of System I is that broken 
 irrigation furrows are not easy to detect. 
 
Orchard layout Systems 
 
 
 §Q 
 
 G — G- 
 
 -o-:-9' 
 
 _-^G 
 ^G 
 
 o 
 
 '/ 
 
 
 
 £> /XX 
 
 • / / 
 
 xx. 
 
 iftG // G^ ^-- ~~T 
 
 /© O^ ^ G G— O ' 
 
 s<X ^G 0--G" a 
 
 .^. v -°nfour Line — " 
 
 System II allows fewer trees per acre: above are 65 trees; at left, 73 trees. 
 
 O^q^o- -Q--G--G 
 
 y WftK U—StnlfU Cross Kows 
 
 SYSTEM II— The other main system of contour 
 planting consists of uneven spacing of trees on 
 the contour grade, with straight crossrows. 
 
 This planting method usually allows fewer 
 trees per acre and is a little harder to lay out 
 than System I. 
 
 An advantage of System II is that, since up- 
 and-down rows are straight, broken irrigation 
 furrows are more easily detected. 
 
 Also, the distribution, servicing and opera- 
 tion of orchard heaters is simplified. 
 
 Cultivation up and down the slope is pos- 
 sible—but not recommended. It tends to leave 
 trees on mounds. 
 
 System II is best suited to smooth, uniform 
 slopes. 
 
 EXAMPLE OF System II, with relatively straight 
 cross rows. 
 
How to lay Out 
 An Orchard 
 
 This undertaking requires skill and 
 judgment. To obtain good results you 
 should adopt a step-by-step procedure. 
 
 First, determine what grade your irri- 
 gation furrows should have, following 
 the chart and instructions on page 7. 
 This should be done carefully and unhur- 
 riedly. You'll find it helpful to examine 
 orchards already planted under condi- 
 tions similar to those on your land. 
 
 Equipment needed 
 to make layout 
 
 Next, gather your equipment. Best, but 
 most expensive, would be an engineer's 
 level, rod, and steel tape. Less expensive 
 but harder to use would be a farm level, a 
 
 cloth tape, and a flexible cloth rod tacked 
 on a 1x3 board. A hand level can be 
 substituted for the farm level on small 
 plantings where great accuracy is not 
 necessary. A hand axe, 4-foot stakes, and 
 16-inch stakes complete the equipment 
 list. (Laths cut in three 16-inch lengths 
 make good stakes.) 
 
 On the following pages the directions 
 for laying out a contour-planted orchard 
 are given in text and photographs. 
 
 Here's how to 
 start the job 
 
 Assume that we are facing a tract of 
 side-hill land. The average slope is 10 
 per cent; tract width is 300 feet; the 
 
 WORK STARTS at first stake in lowest row. Rodman (at right) has moved out 50 feet, setting 
 target for desired grade. Level operator will direct him to move up or down slope until cross- 
 hairs in level coincide with center of target. Rodman will then mark that point with a stake 
 
 and move out another 50 feet. 
 
 
pipeline will be near the left margin; 
 land slope at the pipeline is average for 
 the field ; and the contour rows are to be 
 about 20 feet apart. 
 
 Start the layout in the lower left-hand 
 corner of the field by putting a stake 
 about 6 feet to the right of the pipeline 
 location. From this stake proceed up the 
 hill paralleling the pipeline location and 
 driving stakes every 20 feet. These stakes 
 locate the first tree in each row. 
 
 Second step: locate 
 the tree rows 
 
 Now we are ready for the second step 
 — locating the direction and grade of the 
 tree rows. Set up the level over the first 
 stake. Bring the rod up close to the level 
 and set the target at the same height as 
 the telescope. 
 
 Assume that the telescope is exactly 5 
 feet above the ground. The target would 
 then be set at 5 feet on the rod. 
 
 The rodman then moves across the 
 slope 50 feet, as measured by the tape. 
 Since the contour grade is to be 1% (one 
 foot down for each 100 feet across), the 
 rodman slides the target up one-half foot 
 on the rod (because the distance across 
 the slope is half of 100 feet). The 
 reading on the rod then becomes 5^ 
 feet, and the rodman moves the rod up 
 or down the slope (as directed by the 
 levelman) until the center of the target 
 is level with the telescope. At this point 
 the rodman puts a 4-foot stake in the 
 ground. 
 
 The stake, then, marks a spot 50 feet 
 from the first stake and 6 inches lower 
 in elevation. We now have a start on the 
 desired 1% grade. 
 
 The rodman then moves out another 
 50 feet across the slope, raising the tar- 
 get on the rod another half foot, and the 
 process of sighting-in and marking with 
 a stake is repeated. Each stake in the con- 
 tour row locates a point 6 inches lower 
 than the preceding one. Thus a line of 
 stakes is established across the slope indi- 
 cating a 1% grade. 
 
 TYPICAL PRICES OF 
 
 
 EQUIPMENT (1954) 
 
 
 Builder's level with tripod $150.00 
 
 Farm level with tripod 
 
 75.00 
 
 Engineer's rod with target 
 
 40.00 
 
 Flexible rod 
 
 7.50 
 
 Steel tape and engineer's reel . . 
 
 26.00 
 
 Steel tape (100') in leather case 
 
 15.00 
 
 Cloth tape (100') in leather case 
 
 15.00 
 
 The practice of driving stakes every 50 
 feet is recommended for average condi- 
 tions. When the cross-slope line makes 
 curves sharper than normal, stakes may 
 be needed every 25 or even every 10 feet, 
 to give an accurate line. When this is nec- 
 essary, the rodman adjusts the target to 
 compensate: For stakes 25 feet apart he 
 would move the target one-quarter of a 
 foot (3 inches) ; for stakes 10 feet apart 
 he would move the target one-tenth of a 
 foot. 
 
 When the rodman reaches a point 
 about 300 feet away from the level opera- 
 tor or when he is about to disappear from 
 view around the side of the hill, the level 
 operator should move up to the last ac- 
 curately marked point and set up the 
 level over that point. The process of 
 sighting-in is repeated from there. 
 
 The line of stakes is extended as far 
 as it is desired to plant trees. Then the 
 level is brought back to the pipeline, set 
 up over the stake marking the next row 
 uphill, and the staking process is re- 
 peated. Each row is done in the same 
 way, until the rows are all marked out. 
 
 Stub, fill, and 
 spike rows 
 
 Because of unevenness in topography, 
 the rows will not run exactly parallel to 
 each other. When any row is found to 
 run within less than 18 feet of another 
 row, it should be discontinued; go back 
 and start the next row. The incompleted 
 row is called a stub row. 
 
 When rows separate more than 35 feet, 
 finish the row being worked on, then 
 
 [13] 
 
_,:■:;.,, 
 
 l::stl:,?#ii 
 
 The Operation 
 
 LEVEL is set up over the first stake, and 
 the target on the rod is set at the same 
 height as the telescope on the level. 
 Stakes locate position of the first tree in 
 each row. Here they are 20 feet apart. 
 
 Level is set up 
 over first stake 
 in row. Assume 
 telescope is 5 feet 
 above ground 
 
 To locate tree row 
 on 1 % grade, target 
 on rod is set at 
 5.5 feet to locate 
 point 50 feet away 
 in the row. 
 
 Target on rod will 
 be set at 6 feet 
 to find this point 
 1 00 feet away. 
 
 DIAGRAMMATIC representation of the orchard layout operation shown in the photographs that 
 follow. The level and rod settings are hypothetical. 
 
 [14] 
 
in Pictures 
 
 mm$Mm 
 
 RODMAN has now moved 150 feet from level, setting stakes every 50 feet. When all rows have 
 been staked out, the next step (below) is to mark positions of trees in rows. One man holds 
 tape at stake marking position of first tree (at left), while other man drives stake 20 feet away. 
 
 [15] 
 
H 
 
 ■ 
 
 
 II 
 
 TREE-POSITION stakes have now been driven (the longer grade marker stakes having 
 
 been removed). Note the staggered effect of the stakes, resulting from the uneven 
 
 spacing of stakes in the rows. This illustrates a System I layout. 
 
 THE TWO PLANTING SYSTEMS 
 
 TO LAY OUT an orchard according to System II (straight cross rows), set out two 
 parallel rows of stakes, evenly spaced according to the distance desired between tree 
 cross rows, as in photo below at left. While one man sights between corresponding 
 stakes in top and bottom rows, other man drives tree-position stakes in the grade rows 
 
 (photo at right). 
 
 . 
 
 . 
 
 "F 
 
come back and lay out a row between the 
 two. This is known as a fill row. 
 
 If rows diverge at the far ends, a spike 
 row can be inserted in the same way as 
 the fill row. 
 
 When the rows have been staked out, 
 the spots where trees are to be planted 
 will be marked with 16-inch stakes. 
 
 Tree layouts for 
 systems I and II 
 
 Laying out orchards according to the 
 two planting systems described previ- 
 ously (pages 10, 11) calls for two slightly 
 different procedures. 
 
 Under System I the trees are to be 
 planted at equal intervals along the con- 
 tour grade row; hence the only problem 
 is to space the tree-marker stakes equally. 
 
 Under System II the trees are to be 
 planted at such intervals along the con- 
 tour grade row as will result in straight 
 crossrows. To achieve straight cross- 
 rows, you will need guide lines so that 
 you can align the trees up and down the 
 slope. After you have staked out the row 
 locations, you set up two guide lines at 
 right angles to the pipeline — one near 
 the lower edge of the field, the other near 
 the upper edge. Four-foot stakes are 
 driven at equal intervals on these lines 
 to locate the crossrows. Now, by sight- 
 
 ing along the first stakes in each guide 
 line, tree positions can be located on each 
 contour grade line. Other tree locations 
 are aligned in straight crossrows in the 
 same manner. 
 
 How to locate trees 
 with a grade board 
 
 A grade board (see below) is a simple 
 device which may be used in lieu of a 
 level, rod, and tape to locate the positions 
 of trees on a contour. 
 
 The board should be as long as the de- 
 sired distance between the trees that are 
 to be planted in the orchard — for exam- 
 ple, 20 feet. One end of the board has a 
 fixed, unmovable leg; the other leg is 
 adjustable. The board must be complete- 
 ly rigid over its 20-foot length. 
 
 The short leg may be of any convenient 
 length — say 12 inches. The adjustable leg 
 may then be set to give any desired grade 
 or rate of fall. For trees spaced 20 feet 
 apart on a 1% grade, the adjustable leg 
 should be made 14% inches long. 
 
 Here is how we arrive at the length of 
 14% inches: On a 1% grade a 100-foot 
 row would have a fall of one foot or 12 
 inches. A 20-foot grade board is % of 
 100 feet in length. Therefore, in a 20-foot 
 grade board the fall would be % of 12 
 inches or about 2% inches. Thus the ad- 
 
 GRADE BOARD being used to locate positions of trees. Short leg is held at position of first tree 
 in the row; end of board with long leg is moved up or down the slope until the level bubble is 
 centered. The point where the long leg comes to rest is marked with a stake. This will mark 
 
 position of second tree. 
 
OPERATORS set up third tree position in row. Others are staked out in similar manner. 
 
 justable leg would be 12 plus 2% or 14% 
 inches long. 
 
 Now that the grade board is adjusted, 
 how do we use it? The first tree in each 
 row is located — as before — by a stake 
 about 6 feet from the pipeline. Place the 
 short leg of the grade board next to the 
 stake. The other end extends in the ap- 
 proximate direction of the row. Now 
 move the adjustable end of the board up 
 or down the slope until the level bubble 
 is centered. Place the second stake at this 
 point to indicate where the second tree 
 will be, and continue with the same pro- 
 cedure for the remaining tree locations. 
 
 This method of locating trees will re- 
 sult in an orchard without straight cross 
 rows. 
 
 Planting board puts trees 
 where you want them 
 
 Having gone to the trouble and ex- 
 pense of marking the exact points at 
 which trees are to be planted, you can 
 "protect your investment" by using the 
 planting board. This board insures that 
 trees will be spotted exactly where the 
 markers indicate they should be placed. 
 
 Photos that follow tell how a planting 
 board is used. 
 
 AT LEFT, notch in middle of planting board is placed against tree-marker stake and additional 
 
 stakes are driven into notches at either end of the board. Center stake and board are then 
 
 removed and hole dug for the tree, as shown in photo at right. Planting board is replaced and 
 
 tree positioned in center notch for planting. 
 
 [18] 
 
Some Pointers on 
 Soil Management 
 
 Soil management research tells us to 
 cultivate only when absolutely necessary. 
 In the first place, if cultivation isn't nec- 
 essary it is a waste of time, money, and 
 equipment. Secondly, if the soil is wet, 
 cultivation tends to pack down the earth 
 beneath the layer cultivated, causing wa- 
 ter penetration to be impaired and some- 
 times even hampering root development. 
 There are four main reasons for or- 
 chard cultivation: 
 
 To control weeds or annual pests. 
 
 To prepare land for irrigation. 
 
 To plant a cover crop. 
 
 To work in a cover crop. 
 
 Three cover crop and 
 cultivation systems 
 
 Three systems relating to cover crops 
 and cultivation are most common. 
 
 1 — Winter cover crop, summer 
 tillage: This generally used system is 
 practiced under many soil and climatic 
 conditions. With this system a cover crop 
 should be established each fall to prevent 
 erosion by winter rains. Often it is neces- 
 sary to fertilize the crop for adequate 
 growth. In spring, the crop should be 
 worked into the soil to keep it from com- 
 peting with the trees for moisture and to 
 permit installation of new furrows. 
 
 2 — Permanent cover crop, no till- 
 age: Under this system, furrows are in- 
 stalled and the crop allowed to grow 
 over the entire surface. Results with this 
 method vary greatly. Consequently it is 
 praised and condemned with equal vigor. 
 In any case, it takes great skill and 
 should be used only after careful study. 
 
 The following general statements ap- 
 ply to the permanent-cover-crop-no-till- 
 age method: 
 
 It effectively controls soil erosion. 
 It gives best results on deep and per- 
 meable soils. 
 
 BUT— 
 
 Rodents in the crop are hard to con- 
 trol; they may injure trees by gnawing 
 bark from the tree near the ground level. 
 
 It permits growth of undesirable 
 and difficult-to-control plants such as 
 Bermuda grass. 
 
 Additional water is needed for the 
 cover crop. 
 
 The cover crop can cause fertility 
 problems. 
 
 The cover crop may grow so large it 
 hinders operations. And the dry ma- 
 terial, after mowing, can be a fire hazard. 
 3 — No cover crop, no tillage: At- 
 tention has focused on this system with 
 the development in recent years of oil 
 and chemical sprays for weed control. 
 The practice is spreading rapidly in cit- 
 rus areas and is being used experimen- 
 tally in deciduous orchards. 
 
 An advantage of this system is that the 
 soil usually becomes more porous, thus 
 facilitating irrigation. On the other hand, 
 shorter furrows, requiring extra pipe- 
 lines, become necessary to avoid wasting 
 water through deep percolation. 
 
 Weed-control expense is high for 
 several years but then tapers off. 
 
 Don't cultivate 
 in crossrows 
 
 Steep orchards should be cultivated on 
 the contour — not up and down hill. Im- 
 plement marks up and down hill provide 
 a good start for soil erosion. 
 
 When contour cultivation alone is con- 
 tinued on steeper slopes, bench terraces 
 tend to form. Then, if up-and-down cul- 
 tivation is started, trees are often left on 
 mounds. The resulting uneven ground 
 surface makes irrigation difficult. This 
 can also cause serious erosion from win- 
 ter rains because runoff is concentrated 
 in low spots. 
 
 [19] 
 
Other Applications 
 Of Contour Planting 
 
 Bush berries' on 
 the contour 
 
 In Santa Cruz County a large area of 
 trellised bush berries is irrigated by 
 contour-grade furrows. The plantings are 
 usually on gently rolling land sloping not 
 more than 8%. Grade of rows is about 
 1%. Since the topography is smooth it is 
 not necessary to use stub, spike or fill 
 rows to any great extent. 
 
 In these plantings the distance between 
 the rows is about 8 or 10 feet. Field op- 
 erations are generally performed with 
 tools which make only one trip per row. 
 With such a narrow row sharp curves 
 
 should be avoided as they may impede 
 use of equipment. 
 
 Where a tractor with tools attached is 
 to be used, curves may have a radius as 
 short as 20 feet. But when the tools are 
 pulled behind the tractor the curves 
 should have a radius of not less than 30 
 feet. Try out your tractor and tools first, 
 to see how sharply they can turn in the 
 distance between rows you propose to 
 plant. 
 
 In irrigated vineyards, contour plant- 
 ing is not common, but the practice has 
 merit where the land is steep enough to 
 present a soil-erosion problem. 
 
 Bush Berries Planted on a Contour Grade. 
 
 [20] 
 
Vegetables on slopes 
 of 8 to 10% 
 
 Most vegetable crops are raised on flat 
 bottom land. Some farmers, however, 
 have grown vegetable crops on land slop- 
 ing as much as 8 to 10%. Grades of rows 
 seldom exceed 0.5%. 
 
 Higher lands often have the advantage 
 of being more frost-free than bottom 
 land. Also, south and west exposures are 
 noticeably warmer in winter. 
 
 Disposal of waste water from irriga- 
 tion and rainfall is a serious problem in 
 growing vegetables on the contour. Un- 
 controlled, such water may cause serious 
 gullying. 
 
 One of the best control methods is to 
 establish a grassed waterway for the 
 waste water. Build a wide, shallow ditch 
 and seed it with rye grass or other sod- 
 forming plant. On steep grades it may be 
 well to cover the newly seeded ditch with 
 straw and lightly disk it. Irrigate the 
 
 ditch carefully until a good stand is ob- 
 tained. After that there should be little 
 or no erosion. Lined ditches or concrete 
 pipelines are sometimes used, but these 
 involve substantial cost. 
 
 Strawberries raised 
 on rolling land 
 
 Large acreages of strawberries are 
 raised on rolling land, usually on slopes 
 of less than 6%. 
 
 The soils frequently have a dense clay- 
 pan not more than two feet below the sur- 
 face. Since the soil is shallow, leveling 
 must be limited 
 
 Laying out a commercial planting on 
 such land is usually done by an expert. 
 
 In strawberry plantings, growers pre- 
 fer rows that are straight, about 125 feet 
 long, and level. These three conditions 
 can be met on suitable land without much 
 leveling, although ingenuity and skill 
 may be needed. 
 
 THIS TYPICAL STRAWBERRY planting on sloping land has a wooden flume in the center of the 
 field unit to supply water. The level rows are irrigated both ways from the flume to the roads 
 at the edges of the field. Since the rows are level the furrows between them are really long, 
 narrow basins which fill at each irrigation. There is no run-off after irrigation or rain and there- 
 fore no waste or soil erosion. Slope of the field is about 6%. 
 
 [21] 
 
LEVEL FURROWS in strawberry field stand full of water just after irrigation. Furrows act as 
 
 basins; no water is wasted. 
 
 DIVERGING FURROWS in strawberry field indicate that a change in furrow direction was 
 necessary to keep furrows level without much land leveling. Irrigation water comes from flume 
 
 in foreground. 
 
 1ft - ,ll£3 
 
 [22] 
 
BENCH TERRACES are frequently used on citrus acreages such as this site in Ventura County. Con- 
 tour grade rows are laid out as described in text. Next, bench terraces are made, with the bench 
 sloping slightly toward the hill. Tree rows are then staked out near the margin of each bench. 
 
 REFERENCES 
 
 Irrigation. Essentials of Irrigation and Cultivation of Orchards. 
 
 Frank J. Veihmeyer and Arthur H. Hendrickson. Extension Circular 50, 
 revised March, 1950. 
 
 Cover cropping. Elimination of Tillage in Citrus Soil Management. 
 
 J. C. Johnston and Wallace Sullivan. Extension Circular 150. 
 March, 1949. 
 
 Co-operative Extension work in Agric 
 
 co-operating. Distributed in furtherance of the Acts of Congress 
 
 nd Home Economics 
 
 s. College of Agriculture. University o: 
 of May 8. and June 30, 1914. J. Earl 
 
 f Californi 
 Coke, Dir 
 
 nd United States Department of Agriculture 
 r, California Agricultural Extension Service. 
 
 15wi-9,'54(3142)RMB 
 
fc 
 
 IT JUST COULD BE . . . 
 
 that the farm problems troubling 
 you have also troubled others. 
 
 And it's also possible that with 
 a little help from the right source 
 your problems can be eased, if 
 not cured. 
 
 Here's how to go about getting 
 help. 
 
 Take your problems to your 
 County Farm Advisor. He's an 
 agricultural specialist with a 
 background of practical knowl- 
 edge about farming in your lo- 
 cality. He will help you if he can 
 ... or he will get the information 
 you need from someone who does 
 know the answers. 
 
 Ask your Farm Advisor for a 
 copy of AGRICULTURAL PUBLI- 
 CATIONS— a catalog that lists 
 the bulletins and circulars pro- 
 duced by the University of Cali- 
 fornia College of Agriculture, or 
 write to the address below. 
 
 You'll be amazed at the wide 
 range of information covered in 
 these publications. 
 
 Yes ... it just could be that 
 your problems aren't nearly as 
 hard to solve as you think. Make 
 use of the free services of your 
 University. 
 
 — 
 
 Office of Agricultural Publications 
 
 22 Giannini Hall 
 
 University of California 
 
 Berkeley 4, California