i vis ton of A g r i c u It u r a I S c i e n c e s 
 
 UNIVERSITY OF C A L I F O R N I 
 
 FLAX 
 
 
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 iilSlliiii 
 
 KNOWLES « ISOM • WORKER 
 
 CALIFORNIA AGRICULTUR. 
 Experiment Statio 
 Extension Service 
 
 
Flax Production in California 
 
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 ^:;:<y--..^. 
 
 1935 
 
 1940 
 
 1945 
 
 Year 
 
 1950 
 
 1955 
 
 Flax, a newcomer among California crops, became firmly established 
 as a commercial crop of the Imperial Valley in 1934. Not much later flax 
 production started in the San Joaquin Valley where acreages increased 
 until 1945, then dropped sharply. In the meantime flax was tried as a 
 summer crop in San Mateo County where it has been successfully grown 
 since 1944. 
 
 The Authors: 
 
 P. F. Knowles is Associate Professor of Agronomy and Associate Agronomist in the Experiment 
 Station, Davis; W. H. Isom is Research Agronomist, Crops Research Division, Agricultural Research 
 Service, USDA; G. F. Worker is Assistant Specialist in Agronomy and Superintendent of the 
 Imperial Valley Field Station. 
 
 JULY, 1959 
 
FLAX PRODUCTION 
 
 IN IMPERIAL VALLEY 
 
 J? lax is A cool- weather crop. This 
 characteristic adapts it well to the mild 
 winter climate of Imperial Valley. Ade- 
 quate irrigation water from the Colorado 
 River and commercial fertilizers make 
 flax production possible in this desert 
 region. The ideal winter climate, how- 
 ever, adapts the region to the production 
 of other important crops which compete 
 with flax for acreage. Among the winter 
 crops are barley, sugar beets, lettuce, 
 
 carrots, and other vegetables and small 
 grains. Summer crops are cotton, melons, 
 grain sorghums, and forage sorghums. 
 Alfalfa occupies a rather large acreage 
 both as a winter and summer hay and 
 pasture crop. It is also used to better 
 balance the crop rotation. Because of the 
 competition of these several crops for 
 land, the acreage of each crop is likely to 
 reflect its current price. 
 
 Growth of the flax plant 
 
 Seeds of flax germinate very quickly in 
 the presence of moisture. Under normal 
 field conditions the seedlings appear 
 above the ground in a week, though they 
 may be delayed by cool weather and deep 
 seedings. The seedlings are not vigorous 
 nor highly competitive with weeds. 
 
 If sown in early December the seed- 
 lings grow steadily until they are 4 to 8 
 inches high by the end of January. 
 By mid-March, when blossoming com- 
 mences, the plants are 15 to 30 inches 
 high. There is little increase in height 
 afterwards. The plants usually produce 
 two or more strong lateral branches from 
 the base of the main stem though these 
 may be absent, or their number may be 
 reduced by thick stands or less-than- 
 optimum growth conditions. Smaller 
 branches are abundant in the upper part 
 of the plant, and these branches bear the 
 flowers. 
 
 Flax varieties grown in Imperial Val- 
 
 ley have blue, funnel-shaped flowers. (In 
 other varieties flower color may vary 
 from white, through various shades of 
 blue and pink, to dark lavender. Flowers 
 may vary also in shape and size) . 
 
 Flowering continues over a long pe- 
 riod if the flax plant has sufficient nutri- 
 ents and water. The maximum amount of 
 bloom occurs about one week after flow- 
 ering commences, but the plants continue 
 to bloom for two or three additional 
 weeks. Normally this first flush of bloom 
 produces mature bolls about the first of 
 May. At this time the variety Imperial 
 produces a large second flush of bloom. 
 These will mature in early to mid-June, 
 when a third flush of bloom may occur. 
 These flowering periods are usually re- 
 ferred to as the "first, second and third 
 sets." Flowers open about an hour after 
 sunrise, and the petals fall about noon. 
 Each day produces new flowers. 
 
 The bolls of flax varieties in the Im- 
 
 3] 
 
perial Valley are closed tightly (indehis- 
 cent), and are difficult to thresh without 
 rolls on the combine. Each boll can pro- 
 duce up to 10 seeds, but normally the 
 number varies from 8 to 10. An excep- 
 tional boll may produce more than 10 
 seeds, but it has not been possible to 
 develop a variety that will do this con- 
 sistently. 
 
 Seeds of flax may vary in color from 
 yellow to dark brown, and in size from 
 those weighing 3 grams per 1,000 seed to 
 those weighing 12 grams. The seeds of 
 varieties grown in Imperial Valley are 
 brown, and 1 ,000 of them weigh 6 to 6.5 
 grams. Flax seed is covered with a muci- 
 laginous material that gives it a high 
 gloss. It also causes the seeds to stick 
 together when they are wet. 
 
 The culture of flax 
 
 Flax culture in the Imperial Valley 
 may vary from farm to farm, therefore 
 successful practices will sometimes differ 
 from those described here. The records 
 of farmers participating in production 
 contests have been very helpful in draft- 
 ing the recommendations presented in 
 this circular. 
 
 Climate 
 
 Flax grows best where temperatures 
 are cool during most of the growing 
 season. For this reason it is grown in the 
 
 Northern Great Plains and in coastal 
 areas of San Mateo County as a summer 
 crop, and in Texas and the desert areas 
 of the Southwest as a winter crop. Impe- 
 rial Valley provides an ideal climate for 
 flax, particularly for the varieties grown 
 there. The table below gives some of 
 the statistics on the climate of Imperial 
 Valley. The high summer temperatures of 
 this area begin after flax has completed 
 most of its development. 
 
 In parts of the Northern Great Plains 
 the growing season for flax is not much 
 
 Weather Data from El Centro, California 
 (September 1950 to August 1955)* 
 
 Month 
 
 Rainfall 
 
 Temperatures 
 
 Average 
 maximum 
 
 Average 
 minimum 
 
 Lowest 
 
 Highest 
 
 Average 
 no. days 
 
 below 
 freezing 
 
 Wind speed 
 
 Average 
 
 Maximum 
 
 September 
 October. . 
 November 
 December . 
 January. . 
 February. 
 March. . . 
 
 April 
 
 May 
 
 June 
 
 July 
 
 August . . . 
 
 inches 
 
 Trace 
 00 
 0.14 
 24 
 87 
 05 
 28 
 12 
 00 
 00 
 
 
 
 
 
 
 
 
 
 
 
 
 
 19 
 
 0.76 
 
 105 3 
 
 95 7 
 79 9 
 71 
 69 3 
 74.4 
 78 5 
 87 6 
 
 96 
 103 2 
 108 9 
 107.2 
 
 66 
 
 57 
 
 46 
 
 39 
 
 38 
 
 41 
 
 45 
 
 52 
 
 58 6 
 
 64 8 
 
 76 
 
 74.5 
 
 54 
 40 
 30 
 25 
 26 
 26 
 29 
 34 
 44 
 47 
 52 
 59 
 
 120 
 
 109 
 
 94 
 
 86 
 
 85 
 
 93 
 
 94 
 
 107 
 
 116 
 
 118 
 
 120 
 
 117 
 
 m.p.h. 
 
 7 
 5 
 7 
 7 
 7 
 8 
 8 
 9 
 9 
 8 
 10 
 9 
 
 m.p.h. 
 
 38 
 32 
 35 
 43 
 33 
 38 
 40 
 47 
 35 
 30 
 51 
 54 
 
 From U. S. Weather Bureau records. 
 
 [4] 
 
over 100 days. In Imperial Valley it may 
 extend from November to July, a period 
 of more than 200 days. The long growing 
 season is one reason for the high yields. 
 High or low humidities do not in 
 themselves appear to be important fac- 
 tors in the culture of flax, since the crop 
 thrives in the low humidities of Imperial 
 Valley and the high humidities of San 
 Mateo County. Diseases are often favored 
 by high humidities, rust, Botrytis blight, 
 and pasmo being severe at times in San 
 Mateo County. Anthracnose appeared in 
 the San Joaquin Valley when hot humid 
 conditions prevailed in early spring. 
 
 Soil 
 
 Flax does best on medium-textured soil 
 but is grown in Imperial Valley on soils 
 that are sandy loams and clay loams. 
 With the heavy soils it may be difficult to 
 prepare a suitable seed bed. 
 
 Flax is more sensitive to salty soil 
 than most field crops. It will not thrive 
 nor produce a paying yield if the salt 
 content of the soil extract is above 5 
 millimhos per centimeter. You may ob- 
 tain this measurement in a laboratory 
 prior to planting. 
 
 In the past it was often said that flax 
 was "hard on the soil." Part of this im- 
 
 1945 
 
 Year 
 
 Consistently high flax yields make the Imperial 
 Valley the top flax-producing region of the 
 state. 
 
 pression stemmed from the fact that Fu- 
 sarium wilt spread rapidly in new stands 
 of flax in the Northern Great Plains, and 
 prohibited the production of successive 
 crops of flax. Weeds, commonly a prob- 
 lem in flax fields, may have affected 
 yields of the succeeding crops. Flax does 
 not produce a great volume of organic 
 matter, and may not improve the texture 
 of the soil, but ihere is no record in 
 Imperial Valley that flax in itself has had 
 an adverse effect on the soil. 
 
 Crop Rotations Used in Flax Production, Imperial Valley 
 
 Year in rotation 
 
 1-3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 Alfalfa 
 
 Flax 
 
 Flax 
 
 
 
 
 Alfalfa 
 
 Flax 
 
 Flax 
 
 Flax/milo 
 
 
 
 Alfalfa 
 
 Flax 
 
 Flax 
 
 Barley /milo 
 
 
 
 Alfalfa 
 
 Flax 
 
 Flax/sesbania 
 
 Flax 
 
 
 
 Alfalfa 
 
 Flax 
 
 Flax 
 
 Barley 
 
 Barley 
 
 
 Alfalfa 
 
 Flax 
 
 Barley 
 
 Barley /milo 
 
 
 
 Alfalfa 
 
 Flax 
 
 Flax/milo 
 
 
 
 
 Alfalfa 
 
 Vegetables 
 
 Vegetables 
 
 Flax 
 
 
 
 Alfalfa 
 
 Vegetables 
 
 Vegetables 
 
 Vegetables 
 
 Flax 
 
 Barley 
 
 Alfalfa 
 
 Flax 
 
 Flax/sesbania 
 
 Sugar beets 
 
 Vegetables 
 
 Vegetables 
 
 
 Flax/sesbania 
 
 Flax 
 
 Flax/sesbania 
 
 Flax 
 
 Flax/sesbania 
 
 * From "An economic study of California Flaxseed Production," J. C. Deubner, 1947. 
 
 [5] 
 
Rotation 
 
 Flax is included in many different ro- 
 tations (see listings page 5), but over 
 half the time it follows alfalfa. It is rec- 
 ommended after beets or a vegetable 
 crop that has been kept free of weeds. 
 After barley or wheat it is important to 
 germinate and destroy seeds and seed- 
 lings of these crops, otherwise volunteer 
 plants may become serious weeds in the 
 flax. 
 
 Two or more flax crops may be grown 
 in succession, though weeds may prohibit 
 this practice. Frequently the second crop 
 of flax after alfalfa is higher in yield than 
 the first, presumably because the alfalfa 
 has completely decomposed by the time 
 the second flax crop is planted. On de- 
 composition of the alfalfa residue, nitro- 
 gen becomes available to the flax plants. 
 If grown continuously, diseases some- 
 times increase in flax, most conspicuously 
 
 Fusarium wilt. After alfalfa, cutworms 
 may be a problem. 
 
 The value of sesbania as a cover crop 
 in a rotation with flax has not been 
 proved. Limited experiments would indi- 
 cate that flax yields are not increased 
 following sesbania. 
 
 Varieties 
 
 Punjab (C.I. 20), a selection from an 
 introduction from India, was the first 
 successful variety in Imperial Valley. 
 This variety has been almost completely 
 replaced by the varieties Punjab 47 (C.I. 
 1115) and Imperial (C.I. 1114), both 
 selections from Punjab, made by L. G. 
 Goar, and both released for commercial 
 production in 1947. 
 
 Punjab 47 is slightly higher yielding 
 and somewhat earlier than Punjab, but 
 otherwise very similar to it. Punjab 47 
 was widely grown in Imperial Valley 
 
 How Flax Varieties Compare in Yield, Oil Content, and Iodine Value 
 
 
 Punjab 
 (C.I. 20) 
 
 Punjab 47 
 (C.I. 1115) 
 
 Imperial 
 (CI. 1114) 
 
 Punjab 
 53 
 
 New 
 River 
 
 U.C. Imperial Valley Field Station, El Centro: 
 Yield bu./A 1945-52 
 
 41.2 
 
 39 8 
 
 184 
 
 39 3 
 
 38 4 
 182 
 
 44.3 
 50.4 
 41.0 
 
 41 0* 
 39 8 
 39 4 
 
 184* 
 
 182 
 
 175 
 
 39 3 
 45.9 
 
 39 9 
 
 40 1 
 
 178 
 183 
 
 44 
 50.4 
 47.6 
 
 39.8* 
 
 38.6 
 
 39.2 
 
 184* 
 
 182 
 
 180 
 
 39.2 
 50.0 
 
 38.4 
 38.8 
 
 180 
 183 
 
 45 
 
 45.9 
 
 40.0 
 40 2 
 
 189 
 184 
 
 44.7 
 
 39.8 
 
 189 
 
 
 Yield bu. /A 1952-56 
 
 
 Yield bu./A 1956-57 
 
 44.5 
 
 Oil content in per cent 1945-52 
 
 
 Oil content in per cent 1952-56 
 
 Oil content in per cent 1956-57 
 
 Iodine value 1945-52 
 
 42.0 
 
 Iodine value 1952-56 
 
 
 Iodine value 1956-57 
 
 177 
 
 USDA Southwestern Irrigation Field Station, 
 Brawley : 
 
 Yield, bu.A. 1950-52 
 
 Yield bu./A 1953-57 
 
 48.3 
 
 Oil content in per cent 1950-52 
 
 
 Oil content in per cent 1953-57 
 
 Iodine value 1950-52 
 
 42.1 
 
 Iodine value 1953-57 
 
 184 
 
 
 
 * No data for 1949. 
 
 [6] 
 
following its release as a new variety. It 
 has no resistance to wilt. 
 
 Imperial is somewhat later than Pun- 
 jab, has slightly smaller seeds, and pro- 
 duces a more abundant "second set" of 
 bolls in the late spring than either Punjab 
 or Punjab 47. Where farmers have irri- 
 gated late to get a second set, Imperial 
 has been the highest yielding variety. For 
 this reason it has become increasingly 
 popular in the Imperial Valley. The 
 adoption of this variety with late dates 
 of harvest has required some changes in 
 the culture of flax. It has also led to very 
 high yields. Imperial is not resistant to 
 wilt. 
 
 Punjab 53 was developed by person- 
 nel of the University of California from 
 
 Foundation, registered, and 
 certified seed 
 
 The purity of the flax varieties 
 Punjab 47, Punjab 53, Imperial and 
 New River is maintained through 
 foundation, registered, and certified 
 seed. 
 
 Foundation seed is highly purified 
 seed, grown in small amounts by the 
 University, and distributed to a small 
 number of growers. It is used to pro- 
 duce registered seed, the increase 
 from the latter being called certified 
 seed. 
 
 Certified seed, in most instances, 
 is used to grow commercial seed for 
 crushing, and only in special circum- 
 stances can it be used to produce 
 certified seed for another genera- 
 tion. The Farm Advisors' office in Im- 
 perial County has a list of farmers 
 having registered or certified seed 
 of the different varieties. The list is 
 revised each year. 
 
 In most instances it pays to use 
 certified seed. It assures your getting 
 the correct variety, free from mix- 
 tures and of a high germination rate. 
 
 a wilt-resistant selection of Punjab found 
 in San Mateo County. In the absence of 
 Fusarium wilt, it is not so high yielding 
 as the above three varieties, but where 
 this disease is present Punjab 53 is much 
 superior. Though it has a high degree 
 of resistance to many races of wilt, it 
 is being replaced by New River. 
 
 New River (C.I. 1912), a variety de- 
 veloped by the U. S. Department of Agri- 
 culture, was derived from a cross between 
 Punjab 47 and B-5128 (C.I. 980). It is 
 resistant to most wilt races, and yields 
 about the same as Imperial even where 
 wilt is not a problem. It has a higher oil 
 content than the varieties above. 
 
 All these varieties are very similar in 
 appearance — they have short and 
 branched stems, blue flowers, indehiscent 
 bolls, and brown seed. The results of 
 yield tests in Imperial Valley are given 
 in the table on page 6. 
 
 Varieties from the Great Plains area 
 have been distinctly lower in yield. Some 
 with resistance to disease have been 
 crossed with local varieties and may yield 
 strains superior to anything now avail- 
 able. 
 
 Attempts to develop a flax variety with 
 both high seed and high fiber yield have 
 not been successful. The long-stemmed 
 fiber types have given a low yield of 
 very small seed. 
 
 Seedbed preparation 
 
 The seedbed should be firm, level, and 
 have moist soil as close to the surface as 
 possible. Germinate weed seeds and de- 
 stroy the seedlings before planting. 
 
 When flax is to follow alfalfa or other 
 perennial crops, plow the land in the 
 summer or very early fall. You may turn 
 under the last crop of alfalfa, to increase 
 the organic matter in the soil. After 
 barley, wheat or other winter crops chisel 
 the land in the early summer and leave 
 to aerate until September when it is 
 disked prior to the first pre-irrigation — 
 that is, an irrigation given prior to plant- 
 ing. A summer cover crop before the flax 
 
 [7] 
 
Foundation seed of Punjab 47 at the Imperial 
 Valley Field Station, grown under isolation and 
 all off-types rogued out. 
 
 should be plowed under in August while 
 it is still green. After a row crop such as 
 melons, lettuce, or carrots, deep tillage 
 probably is not necessary, and disking 
 will suffice. 
 
 About September 1 or shortly there- 
 after prepare the land for a pre-irriga- 
 tion. After disking, make the irrigation 
 levees or "borders," parallel to one an- 
 other and 40 to 60 feet apart. The en- 
 closed areas, the "checks," may vary in 
 length from 300 feet to % mile. The 
 
 Pre-irrigation for flax in November aims at 
 water penetration to a depth of 3 to 4 feet. 
 
 length and width of the checks depend 
 upon the volume of water delivered at 
 the head of the check and the type of soil. 
 On sandy soil make the checks narrower 
 and shorter because they lead to more 
 economical use of water. Leave the bor- 
 ders as low as possible — the settled 
 height should be about 6 inches. This 
 permits easier planting and harvesting. 
 
 If you use a single pre-irrigation, allow 
 10 to 25 days before seeding: a short 
 period for light or sandy soils and a 
 longer period for heavy soils. 
 
 Apply enough water to wet the ground 
 to a depth of 3 to 4 feet. Soil should be 
 saturated through the effective root zone, 
 and water should move into the tile 
 lines. When the soil has dried sufficiently, 
 give it a shallow cultivation (mulching), 
 thorough enough to kill all weeds. Avoid 
 deep cultivation because it will bring 
 weed seeds up from lower levels, and 
 these will germinate and grow with the 
 flax. A spring-toothed harrow or a mulch- 
 ing disk followed by a spike-toothed har- 
 row is usually sufficient. A packer or 
 roller may be used in some cases to firm 
 the soil. If the soil is weedy, it may be 
 advisable to let a second crop of weed 
 seeds germinate, and then cultivate a 
 second time (double mulching). 
 
 Two pre-irrigations have been used by 
 many farmers to good advantage. The 
 timing of these pre-irrigations will de- 
 pend upon the date of planting, but the 
 first may be given as early as mid-Sep- 
 tember. The first irrigation will germi- 
 nate some seeds of both summer and 
 winter weeds, and also indicate the high 
 and low spots in the field which may be 
 eliminated by landplanning before the 
 second pre-irrigation. Destroy the weeds 
 about six weeks later, in the manner de- 
 scribed above. After the last cultivation, 
 sow the flax immediately. 
 
 Preplanting fertilization 
 
 Fertilizer recommendations vary from 
 farm to farm, and are influenced on the 
 same farm by the various soil types and 
 
the previous history of cropping and fer- 
 tilizing. 
 
 Phosphorus (P) has been used rather 
 liberally in Imperial Valley, and many 
 fields show no response to its use. If 
 used, 40 to 80 pounds per acre of P 2 ; - 
 should be adequate. Apply it just ahead 
 of the last pre-irrigation, either as broad- 
 cast on the surface of the soil or drilled 
 in to a depth of 4 to 5 inches. 
 
 Apply part or all the nitrogen (N) fer- 
 tilizer at the same time as the phos- 
 phorus. You may use a combination- 
 type fertilizer such as 13-39-0, 16-20-0, 
 or 11-48-0 (nitrogen, phosphorus, and 
 potassium, respectively). At this time, 
 apply 40 to 100 pounds of nitrogen. On 
 sandy soils use the ammonia form or urea 
 rather than the nitrate form, since the 
 latter may be readily leached from the 
 surface layers by irrigation water. The 
 form appears to be less important with 
 the heavy clay soils. 
 
 There is no evidence that flax in Im- 
 perial Valley benefits from potassium 
 (K) fertilizers. Neither have flax yields 
 been improved by the use of micronu- 
 trients. 
 
 Fertilizers are sometimes applied be- 
 fore the cultivations prior to the last pre- 
 irrigation. However, if temperatures are 
 high at this time, much of the ammoni- 
 acal nitrogen may quickly change to the 
 nitrate form, be leached from the surface 
 layers of soil, and perhaps lost to the 
 flax crop. 
 
 Planting 
 
 Equipment: Usually a grain drill is 
 used for planting. It should be set to 
 place the seed into moist soil about % to 
 1 inch, but at the same time as shallow 
 
 Top: Cultivation with a spring tooth harrow 
 after the first irrigation, destroying a heavy 
 stand of small weeds. Center: Mulching with 
 spring tooth and spike tooth harrows. Bottom: 
 Double-disk planter with press wheels and culti- 
 packer. The press wheels run in the bottom of 
 the furrows behind the planters, and firm the 
 soil about the seed. 
 
 
 i^ 
 
 
as possible. In desert areas, where rain 
 rarely occurs at the time of seeding, good 
 stands are obtained by planting to a total 
 depth of 2 or even 3 inches, if the sur- 
 face soil is dry and fine, and the seed is 
 placed in firm moist soil. A drill with a 
 shoe-type or double disk opener and in- 
 dividual press wheels is most suitable 
 since it places the seed into moist soil 
 without covering the seed too much. 
 Packing after seeding may be desirable 
 if the drill does not have press wheels. 
 Avoid planting in soil that is so wet that 
 it will not close around the seed. The seed 
 will not germinate if it sits in the bottom 
 of an open furrow. 
 
 Broadcasting and harrowing is not 
 recommended, because these practices 
 place many of the seeds too deep, or too 
 shallow, to produce seedlings. Also, 
 broadcasting usually requires an irriga- 
 tion to germinate the seed; and an irriga- 
 tion after broadcasting, or after drilling 
 the seed near the surface in dry soil, ger- 
 minates many weed seeds and may crust 
 the soil. 
 
 The common practice is to drill length- 
 wise of the checks. Drilling crosswise is 
 more difficult, and often leads to uneven 
 stands on each side of the borders be- 
 cause the seed is sown too deep or too 
 shallow. However, some of the advan- 
 tages of drilling crosswise are: 
 
 • the borders grow flax instead of weeds, 
 
 • the drill furrows lead to more uniform 
 distribution of water, and 
 
 • the furrows on each side of the border 
 are partially filled which makes harvest- 
 ing easier. 
 
 Rate: The rate of seeding in close-drill 
 rows (6 to 8 inches apart) should be 
 about 42 pounds per acre. It may be in- 
 creased to 50 to 60 pounds per acre if 
 curly top is expected. Excessively heavy 
 stands, however, frequently lodge be- 
 cause the plants are crowded and stems 
 thin and elongated. 
 
 At 42 pounds per acre, you sow be- 
 tween 60 and 70 seeds per square foot. 
 If % to % of these develop into seed- 
 
 lings, the stand is adequate. If plants are 
 about y 2 inch apart in rows 6 to 8 inches 
 apart, the stand is satisfactory. 
 
 Seed treatment: Treat the seed with 
 a fungicide to kill any disease that may 
 be present on the surface of the seed. 
 Currently recommended fungicides are 
 Ceresan M and Arasan SFX. A recom- 
 mended fungicide will also protect the 
 germinating seed from root rots, this 
 being particularly important where ger- 
 mination proceeds slowly because the 
 soil is cold and wet. The protection that a 
 fungicide affords the young seedling does 
 not extend beyond its emergence above 
 the surface of the soil. Use fungicides at 
 the rate recommended by the manufac- 
 turer, and apply them as either a dust or 
 slurry. Most seed flax supplied by Impe- 
 rial Valley firms and organizations is 
 treated prior to sale to farmers. 
 
 Date: When Punjab and Punjab 47 
 were the varieties commonly grown, the 
 period from November 7 to December 7 
 was most suitable for planting. These 
 varieties were harvested in May and 
 June. With Imperial, which is harvested 
 in July, plantings made during the first 
 two weeks of December have been higher 
 yielding in many cases than those made 
 earlier or later. If sown in October, buds 
 and flowers may appear early enough in 
 February or March to be damaged by 
 frosts. Appreciable amounts of flax have 
 been successfully and profitably sown in 
 late January and early February after an 
 early crop of lettuce or carrots. Plant 
 height will decrease with later plantings. 
 
 Row culture: Though not a frequent 
 practice, flax has been grown success- 
 fully in Imperial Valley as a cultivated 
 wide-row crop. At spacings of 24 inches 
 or less between rows, yields have been 
 similar to those where drill rows were 6 
 to 8 inches apart. In wide-row plantings 
 it is preferable if the rows run in a north- 
 south direction to promote a set of bolls 
 on both sides of the row. Rows running 
 east to west produce more bolls on the 
 south side, and may lodge in that direc- 
 
 [10] 
 
tion. Rates of seeding: for 13-inch rows 
 32 pounds per acre; for 21 -inch rows 28 
 pounds; and for 24-inch rows 24 pounds. 
 
 Irrigation 
 
 Irrigate 6 to 8 weeks after planting 
 when the plants are 4 to 8 inches high, 
 and before they develop a deep green or 
 bluish color which indicates stress from 
 lack of water. However, an irrigation 
 trial in a commercial field in 1955-56 
 (see table below) indicated that the 
 initial irrigation after planting should be 
 delayed as long as possible without allow- 
 ing the plants to wilt. Early irrigations 
 encourage weeds, root rots and lodging. 
 
 Give the second irrigation about one 
 month after the first, when the plants are 
 in full bloom. Delaying the second irriga- 
 tion much beyond 30 days has caused a 
 reduction in yield. Frequent irrigations 
 before full bloom may promote lodging 
 which results in lower yields. 
 
 Provide succeeding irrigations often 
 enough to prevent stress from drought. 
 Soil type, weather conditions, and stage 
 of growth will regulate the applications. 
 It is a bad practice to irrigate by the cal- 
 endar. 
 
 For a second set of bolls and maximum 
 yields, continue irrigations into June; 
 keep irrigating so long as the flax stands 
 upright, remains green, and continues to 
 bloom. Ten or more irrigations may be 
 necessary. 
 
 Since flax bolls mature successively 
 over a long period, it is difficult to state 
 
 in terms of their development when irri- 
 gations should cease. Normally they will 
 stop about three weeks before harvest. 
 The total water used on flax amounts to 
 3 to 4 acre feet. 
 
 Frost damage 
 
 Damage to flax from frost occurs al- 
 most every year in the Imperial Valley. 
 Most often it occurs in early March, when 
 temperatures of 28° to 30° F kill blos- 
 soms and young bolls — the rest of the 
 plant is unaffected. Very often damage 
 is not apparent until the affected bolls 
 fail to develop and turn brown. Undoubt- 
 edly frost causes some loss in yield, 
 though it has never been precisely meas- 
 ured. 
 
 When seedlings first appear above 
 ground they are somewhat susceptible to 
 frost. Temperatures below 18° to 26° F 
 may kill them. After true leaves have 
 formed and before flower buds appear, 
 flax, in certain cases, has survived tem- 
 peratures down to 15° F. At this stage, 
 though frost may kill almost all the aerial 
 parts of the plant, the main stem develops 
 new branches at its base. 
 
 Damage from frost is affected by many 
 factors. A period of cool weather prior 
 to the frost will harden the plant, and 
 thereby reduce damage. Bright sunlight 
 and drying winds after a freeze may 
 magnify its effect. Frost will do less dam- 
 age if the level of soil moisture is high. 
 For this reason many farmers irrigate 
 their flax if frost is expected. 
 
 
 Effect of Irrigation Sched 
 
 ule on 
 
 Yields 
 
 
 
 
 Irrigations ( v ) at the following number of days after planting 
 
 Yield 
 
 
 49 
 
 58 
 
 89 
 
 108 
 
 121 
 
 128 
 
 141 
 
 156 
 
 161 
 
 
 
 
 
 
 
 
 
 
 
 bu/A 
 
 Trial 1 
 
 
 V 
 
 V 
 
 V 
 
 V 
 
 
 V 
 
 V 
 
 V 
 
 44.3 
 
 Trial2 
 
 V 
 
 
 V 
 
 V 
 
 V 
 
 
 V 
 
 V 
 
 V 
 
 39 6 
 
 Trial 3 
 
 
 V 
 
 
 V 
 
 
 V 
 
 V 
 
 V 
 
 V 
 
 38 1 
 
 Trial4 
 
 V 
 
 
 
 
 V 
 
 
 V 
 
 V 
 
 V 
 
 34.2 
 
 In all four trials flax was planted November 15 at 50 lb/A. 150 lb. N and 80 lb P2O5/A applied before planting, 
 50 lb P 2 6 at second irrigation, and 40 lb N in March. Soil type was Meloland fine sandy loam. 
 
 [ii] 
 
Postemergence fertilization 
 
 In recent years, as the culture of flax 
 has been extended into June and July, 
 more and more nitrogen fertilizer has 
 been applied to the growing crop. The 
 total amount of applied nitrogen, includ- 
 ing preplant application, has often been 
 as high as 200 pounds per acre. If nitro- 
 gen is not lost through leaching, 150 
 pounds per acre should be sufficient for 
 maximum yields, even when following 
 nitrogen-depleting crops such as sudan- 
 grass, sorghums and cotton. 
 
 Normally, large amounts of nitrogen 
 should not be required when the flax is in 
 the seedling stage. Some may be neces- 
 sary if the plants are unthrifty or yellow- 
 ish green. At this stage nitrogen is ap- 
 plied most efficiently by broadcasting 
 ammonium sulfate or nitrate from a 
 ground rig and irrigating immediately. 
 Broadcasting is best done when the plants 
 are dry, to avoid burning of foliage. 
 
 Postemergence fertilization is most 
 effective when the plants are in bloom. 
 There is some evidence that the second 
 set of bolls is increased by nitrogen fer- 
 tilizer which was applied when the sec- 
 ond set of blooms appeared. 
 
 Postemergence nitrogen is often ap- 
 plied in the irrigation water in the form 
 of anhydrous ammonia, aqua ammonia, 
 or an ammonium nitrate solution. This 
 usually leads to inefficient use of the ni- 
 trogen, since more irrigation water (and 
 too much nitrogen) is taken into the 
 front and back ends of the checks than 
 in the middle. Some ammonia volatilizes 
 during the application, and the loss will 
 be higher as the temperature, akalinity 
 and aeration of the water increases. Up 
 to 25 per cent of the nitrogen may be 
 lost in this manner. When you do apply 
 nitrogen in irrigation water to seedling 
 plants, keep the amount below 60 pounds 
 per acre. Amounts above 90 pounds per 
 acre have caused some damage to plants 
 by defoliation, but the degree of damage 
 has not been determined experimentally. 
 
 Airplane applications of nitrogen 
 fertilizer to plants past the seedling stage 
 deserve serious consideration. While such 
 applications are costly ($1.50 to $2.00 
 per acre for the application alone) they 
 do permit even distribution, and there is 
 practically no loss through volatilization. 
 Apply at a time when there is no dew on 
 the plants, and follow up immediately 
 with an irrigation. 
 
 Weed control and 
 other uses of herbicides 
 
 Flax, a small plant and not strongly 
 competitive, is easily overcome by weeds, 
 particularly if both emerge at the same 
 time. Weeds not only greatly reduce the 
 yield of the flax, but may also decrease 
 the oil content and iodine value of the 
 oil (see table on page 13). Green weed 
 seeds in the harvested flax seed may 
 cause heating and damage. 
 
 The most serious winter weeds affect- 
 ing flax in the Imperial Valley are wild 
 oats, canary grass, wild mustard, Indian 
 mustard, lambsquarters, nettle-leafed 
 goosefoot, wild beets, sour clover and 
 redweed. Troublesome summer weeds are 
 wild sunflower, pigweed and water grass. 
 (The scientific names of these weeds 
 appear on page 27.) Volunteer barley, 
 wheat, oats, grain sorghum and sudan- 
 grass may also behave as weeds in flax 
 fields. 
 
 Much of the information on weed 
 control with herbicides has been de- 
 veloped during the past few years. 
 With new herbicides appearing each 
 year the recommendations made 
 here will change. See your local 
 University of California Farm Advi- 
 sor for new developments. Also 
 remember: permanent control of 
 weeds is dependent upon good cul- 
 tural and rotational practices; herbi- 
 cides are not substitutes. 
 
 [12] 
 
Weeds Reduce Yield, Oil Content, Iodine Value 
 (Test of herbicides on flax at the Imperial Valley Field Station) 
 
 Herbicide 
 
 On Punjab 47, moderately heavy stand of broad- 
 leaved weeds, 1951-1952: 
 
 No herbicide, weeds removed 
 
 No herbicide, weeds not removed 
 
 2,4-D, triethanolamine salt 
 
 MCP, diethanolamine salt 
 
 2,4-D, triethanolamine salt and IPC| 
 
 MCP, diethanolamine salt and IPCf 
 
 On Punjab 47, heavy stand of canary grass, 1951-1952 
 
 No herbicide, weeds removed 
 
 No herbicide, weeds not removed 
 
 IPC, 50 per cent wettable powder 
 
 IPC, 50 per cent wettable powder 
 
 IPC, emulsified 
 
 IPC, emulsified 
 
 IPC, chlorinated 
 
 IPC, chlorinated 
 
 Rate of 
 application 
 
 lb/A 
 
 Yield 
 
 bu/A 
 
 56 
 32 3 
 55 5 
 45 5' 
 52 4 
 44 5' 
 
 53 
 16 
 53 
 49 
 53 
 
 52 8 
 31 7 
 31 5 
 
 Oil analyses 
 
 per cent 
 
 36 7 
 34.4 
 
 37 8 
 
 38 2 
 
 36 9 
 
 37 9 
 37 8 
 37 6 
 
 iodine 
 value 
 
 182 
 168 
 181 
 179 
 180 
 179 
 178 
 177 
 
 * Sour clover not killed. 
 
 t 50 per cent wettable IPC at 3 lb. actual IPC per acre. 
 
 Weed-control experiment: the left side of the field is heavily infested with wild oats and canary 
 grass; the right side is controlled with 4 pounds of IPC per acre. 
 
Left: Wild sunflower, a serious summer weed in flax. Right: Canary gra< 
 
 winter weed. 
 
 an important 
 
 Herbicides for broad-leaved weeds 
 
 Compounds of 2,4-D (2,4-dichloro- 
 phenoxyacetic acid) : 2,4-D is a hor- 
 mone-type herbicide which interferes 
 with some of the vital processes of sus- 
 ceptible plants, causing severe plant dis- 
 tortion or death within one to three 
 weeks. Flax, however, is tolerant of 2,4-D 
 if the material is properly used. Flax 
 may show some twisting of stems shortly 
 after the application of the 2,4-D, but 
 this is usually offset by new growth later 
 on. Applications cost $2.50 to $3.00 per 
 acre. Field experience and research (see 
 table on page 13) indicate that 2,4-D 
 will control broad-leaved weeds such as 
 mustard and lambsquarters, and that it 
 should be used in the following manner: 
 
 Use the amine salt of 2,4-D. It is sold 
 as a liquid and goes readily into solution 
 in water. The sodium and ammonium 
 salts are about as effective as the amine, 
 but more difficult to handle because they 
 are solids. Ester compounds are more 
 toxic to flax, and their volatile nature re- 
 stricts their use in Imperial Valley. 
 
 Use % pound of actual 2,4-D per acre. 
 This is IV2 pints if the formulation con- 
 tains 4 pounds per gallon. Apply with 
 a ground sprayer with 35 to 50 gallons of 
 water per acre. Pressure in the sprayer 
 should be 20-40 pounds per square inch 
 and the nozzle size No. 8008. Increase the 
 pressure as the forward speed of the rig 
 is increased. 
 
 Apply as soon as possible after the first 
 irrigation when seedlings of broad-leaved 
 weeds have two or three leaves. Apply 
 earlier if vigorously growing weed seed- 
 lings appear before the first irrigation. 
 For best results, apply when the flax 
 seedlings are 3 to 4 inches high, and 
 preferably not over 8 inches, and when 
 the weed seedlings are not higher than 5 
 inches and growing vigorously. Late- 
 season applications are not advisable as 
 2,4-D is very toxic to buds, flowers and 
 young bolls. Spraying when temperatures 
 are high (over 85° F.) in the early fall 
 or the late spring is more conducive to 
 flax injury than when temperatures are 
 cool. 
 
 [14] 
 
Do not use 2,4-D on fields of flax 
 heavily infected with curly top. Appar- 
 ently the plants are in a weakened condi- 
 tion, and more sensitive to damage from 
 2,4-D. 
 
 Compounds of MCP (2-methyl-4-chlo- 
 rophenoxyacetic acid) : MCP is very 
 similar to 2,4-D in its effect on most 
 plants. It is more expensive than 2,4-D, 
 with applications costing $4.00 to $5.00 
 per acre. Rather limited data from Cali- 
 fornia would indicate that MCP is less 
 toxic to flax, and less toxic to some 
 weeds. In one test (table, page 13), it 
 was less effective than 2,4-D in control- 
 ling sour clover. Rate, timing, and other 
 procedures of applying MCP are the 
 same as for 2,4-D. 
 
 Herbicides for grasses 
 
 IPC (Isopropyl-N-phenyl carbamate) : 
 IPC has been successfully used in the 
 control of wild oats and canary grass. It 
 inhibits cell division, but slows down or 
 stops the growth of grasses only if it is 
 washed into contact with the roots by 
 irrigation water or rain. For this reason 
 grasses on the borders of checks will not 
 be controlled if they remain dry during 
 an irrigation. IPC has no herbicidal ef- 
 fect on above-ground portions of the 
 grass plant even if applied to them as a 
 spray. Flax treated with IPC may be re- 
 duced in height. The cost lies between 
 $10.00 and $12.00 per acre. Experience 
 and research (table, page 13) indicates 
 that IPC be used in the following manner: 
 
 Use the 50 per cent wettable powder or 
 emulsion. The pelleted forms (tested in 
 limited experiments) were not uniform 
 in their effect — some flax plants were in- 
 jured and some grass plants were un- 
 affected, probably because of uneven 
 distribution of the pellets. Do not use 
 the chlorinated forms of IPC as they are 
 very toxic to flax. 
 
 Apply at 3 to 4 pounds of actual IPC 
 in 35 to 50 gallons of water per acre with 
 a ground sprayer using pressures of 40 
 to 60 pounds per square inch. Include 
 
 [15 
 
 adequate agitation in the spray tank to 
 insure even distribution of the material. 
 Apply before an irrigation when the 
 flax is 2 inches and grass seedlings less 
 than 5 inches high. 
 
 Harvest-time spraying for 
 weed control 
 
 Where flax fields at harvest time are 
 infested with large broad-leaved weeds, 
 preharvest spraying may eliminate the 
 necessity of windrowing. This treatment 
 dries up both the green weeds and the 
 late flax. It also permits earlier harvest- 
 ing and may reduce the amounts of dock- 
 age with the seed. Spraying does not dry 
 up the weeds where the weed stands are 
 so heavy that their tops form a canopy 
 and prevent penetration of the dessicat- 
 ing spray. The lower portions remain 
 unsprayed and green, and direct com- 
 bining of this material is impossible. 
 Windrowing after a preharvest spray 
 may then result in some loss of flax be- 
 cause the spray has made the plants brit- 
 tle and susceptible to shattering. Spraying 
 costs between $6.00 and $10.00 per acre. 
 Use it in the following manner: 
 
 For each acre use 1 to 3 pints of dinitro 
 general weed killer mixed with 8 to 15 
 gallons of diesel oil or weed oil. Use the 
 smaller amount where moderate amounts 
 of weeds are present, the larger where 
 weed stands are heavy. Apply by air- 
 plane. 
 
 Apply when the flax is ripe. Harvesting 
 should be completed within a week after 
 treatment, or the weeds may become 
 green again and require another treat- 
 ment to permit direct combining. Some 
 shattering of the flax may occur under 
 this preharvest treatment but this shat- 
 tering is usually less than that from 
 windrowing. 
 
 Herbicides not recommended 
 
 Dinitro selectives: They are not as con- 
 sistently effective as 2,4-D in controlling 
 broad-leaved weeds and sometimes cause 
 injury to the flax. Until replaced by 2,4-D 
 
 ] 
 
the most widely used was dinitro-ortho- 
 cresylate applied with ammonium sul- 
 fate. The ammonium salt of dinitro- 
 ortho-secondary-butyl-phenol was also 
 used without ammonium sulfate. 
 
 Oil sprays (mixture of kerosene and 
 aromatic hydrocarbons) : The high cost 
 of $16.00 to $20.00 per acre prohibits 
 their use on flax. 
 
 TCA (Trichloroacetic acid) : This 
 compound, though used effectively in the 
 control of some annual grasses in the 
 Northern Great Plains, does not control 
 wild oats or the broad-leaved weeds of 
 flax in the Imperial Valley. 
 
 Dalapon (Sodium salt of 2,2-dichloro- 
 propionic acid) : Dalapon delays blos- 
 soming, maturity, and causes boll ste- 
 rility in flax. When rates of 3, 4, and 6 
 pounds per acre were used on the variety 
 Imperial, yields were reduced from 67 
 to 52, 42, and 34 bushels per acre re- 
 spectively. 
 
 Maleic hydrazide: This herbicide has 
 been toxic to both flax and wild oats. 
 
 Herbicides to delay blooming 
 and escape frost damage 
 
 This practice is of doubtful value be- 
 cause it is difficult to predict the effect of 
 the spray in this regard. It also requires 
 the ability to predict the occurrence of 
 frost a few weeks in advance. 
 
 Herbicides to shorten and 
 stiffen the straw 
 
 Herbicides can be used to shorten the 
 stems of flax, but this may be accom- 
 panied with a loss in yield. The plants 
 often stand better simply because they 
 have a smaller boll load to support. 
 
 Herbicides to cause branching 
 
 If the growing point of the stem is 
 killed by a herbicide the stem will de- 
 velop numerous branches immediately 
 below the dead portion. Often these are 
 spindly and weak, and there are no data 
 to indicate that yield is increased by the 
 herbicide. 
 
 Combined applications 
 
 A combination of 2,4-D and IPC has 
 not been too successful. This may be due 
 to the stress they place upon the flax, or 
 it may be that they should be used at 
 different times. IPC is best applied im- 
 mediately before an irrigation, and 2,4-D 
 immediately after. 
 
 Disease control 
 
 Only a few flax diseases are trouble- 
 some in Imperial Valley, including Fu- 
 sarium wilt, Rhizoctonia, and curly top. 
 
 Disease-free seed: The original lot 
 of Punjab seed used commercially in the 
 Imperial Valley probably was free of 
 diseases peculiar to flax. This would ex- 
 plain why flax in the Imperial Valley was 
 not troubled by such diseases for so many 
 years. The use of disease-free seed is par- 
 ticularly important if flax is moved from 
 one county to another. 
 
 Seed treatment: Seed treatment kills 
 spores of diseases present on the surface 
 of the seed, but unfortunately does not 
 penetrate inside. Seed treatment will also 
 protect the germinating seedling for a 
 few days, but only in the area of the seed. 
 It will not control diseases such as Fu- 
 sarium wilt that may be carried inside 
 small sections of flax stems mixed with 
 the flax seed. 
 
 Rotation: In the Imperial Valley ro- 
 tations have not been effective in con- 
 trolling Fusarium wilt and Rhizoctonia. 
 the two most serious soil inhabiting 
 pathogens of flax in that area. Rhizoc- 
 tonia, of course, attacks many other crop 
 plants. 
 
 Disease-resistant varieties: The 
 flaxseed industry at the beginning of the 
 century was threatened with destruction 
 by Fusarium wilt, but was saved by wilt- 
 resistant varieties. In the past 25 years 
 resistant varieties have eliminated flax 
 rust as an important disease in the North- 
 ern Great Plains. 
 
 The frustrating feature to the plant 
 breeder is that the organisms causing dis- 
 ease — like crop plants — have many dif- 
 
 [16] 
 
Left: Fusarium wilt attacking flax seedling. Note how the tip of the plant bends over sharply. 
 Right: Flax plants killed by Fusarium wilt. This disease will kill susceptible varieties at any stage 
 in development. 
 
 ferent varieties — usually called strains or 
 races. A variety of flax may be resistant 
 to one race and susceptible to another. 
 That is the situation with both Punjab 53 
 and New River; they are resistant to 
 many races of Fusarium wilt, but not to 
 them all. 
 
 Fusarium wilt was first found in Im- 
 perial Valley in 1945, some eleven years 
 after flax was grown commercially in 
 that area. Since then it has become wide- 
 spread in the Valley, and some fields are 
 
 infested to a point where susceptible flax 
 varieties can no longer be grown. 
 
 Fusarium is a soil inhabiting fungus 
 that can attack flax at any stage. Because 
 it prefers temperatures of 70 to 90° F. 
 for best development, it frequently does 
 not seriously damage flax in Imperial 
 Valley until March. It can live on dead 
 organic matter in the soil an indefinite 
 period of time. This makes it difficult to 
 control with crop rotation. It will not 
 attack other crop plants. 
 
 Sample of the vast number of flax varieties tested for their resistance to many races of 
 
 Fusarium wilt. 
 
 PUNJAfV; 
 
 PUNJABI 
 
 IMPERIAL] 
 
 r v 
 
 4 
 
 ,yv 
 
 t*: 
 
The disease usually appears first as 
 small patches of dead flax. Patches one 
 or two feet in diameter indicate that the 
 disease has been present for two years. 
 With each succeeding crop of flax on the 
 same ground the wilt patches in a field 
 will increase in size, and usually become 
 irregular in shape because of movement 
 of the pathogen by cultivating equipment 
 or irrigation water. 
 
 Rhizoctonia seedling blight. This 
 disease has frequently caused rather seri- 
 ous damage to some fields of flax in Im- 
 perial Valley. It is more severe when 
 young seedlings grow in soil that remains 
 wet on the surface. The causal agent of 
 this disease attacks many other crop 
 plants, including alfalfa, sugar beets, cot- 
 ton, beans, and carrots. 
 
 Like Fusarium wilt this disease can 
 persist in the soil on decaying organic 
 matter. Symptoms of the disease are 
 similar to those of Fusarium wilt. It may- 
 appear in large or small patches. Rhizoc- 
 
 tonia has recently been reported as caus- 
 ing death of flax plants in Imperial 
 Valley during the blossoming and seed- 
 set period. At this stage it may be con- 
 fused with Fusarium wilt. 
 
 Curly top was first observed on flax 
 in California in March of 1944 when 
 several fields in the San Joaquin Valley 
 showed symptoms of the disease. With 
 increases in the acreage of sugar beets in 
 Imperial Valley, curly top has frequently 
 been observed there. Damage was rarely 
 as high as 5 per cent until 1955-56. In 
 1956 curly top was present in most fields, 
 the number of infected plants ranging 
 from 1 to 90 per cent. Estimates of the 
 areas damaged by curly top varied from 
 4,000 to 12,000 acres. 
 
 Curly top is a virus disease originally 
 described on sugar beet. The virus is 
 spread from diseased to healthly plants 
 during the process of feeding by the 
 sugar beet leafhopper. In 1955-56 leaf- 
 hopper counts ranged from 8 to 10 per 
 
 
 Effect of curly top on the bolls and seed of flax in Imperial Valley. The sample on the left is 
 normal, the one on the right diseased. The seed samples in each case were obtained from 20 bolls. 
 
 [18] 
 
100 sweeps in poor fields of flax to 1 per 
 100 sweeps in good fields. It is usually 
 more severe in thin stands of flax, appar- 
 ently because the leafhopper prefers to 
 feed in such situations. The disease is 
 not seed borne. 
 
 The disease may take various expres- 
 sions. The most striking and distinct 
 symptoms are distortion of the leaves of 
 the growing point and puckering or blis- 
 tering of the flowers. The branches may 
 be spreading rather than upright and 
 young plants may turn yellow and die. 
 The most common symptom is a general 
 yellowing of the plants, which is difficult 
 to distinguish from nitrogen deficiency. 
 The latter, however, is expressed more 
 uniformly over the field, whereas curly 
 top begins along the borders in thin and 
 weak spots. The flowers of plants affected 
 by curly top will often fail to open prop- 
 erly or adhere to the boll, but normal 
 flowers of the second set often have this 
 appearance. Infected plants usually pro- 
 duce a poor set of shrunken seed. When 
 cut in cross section the root or crown will 
 often show in the inner bark tissues an 
 orange-yellow discoloration, which may 
 be localized on one side or in one area. 
 
 Fields planted in December, January, 
 and early February show less damage 
 than those sown earlier or later. Damage 
 is reduced in good stands of flax that 
 grow vigorously. Avoid stresses from 
 lack of water or lack of fertilizer. Herbi- 
 cides at the recommended rates may 
 cause serious damage in fields with curly 
 top. 
 
 To reduce populations of the leaf- 
 hopper 
 
 • control weeds which are hosts (lambs- 
 quarter, pigweed, mustard, Indian mus- 
 tard, wild beets, five-hook bassia, and 
 others), or 
 
 • maintain a beet-free period from early 
 July to September. 
 
 Chemical control of the insect in the 
 field has not been successful in control- 
 ling the disease. 
 
 Diseases not present 
 in Imperial Valley 
 
 Anthracnose, a disease of humid 
 areas, causes brown lesions on the plant. 
 
 Botrytis blight, also a disease of hu- 
 mid areas, usually affects only small por- 
 tions of the plant — a single boll or 
 branch. 
 
 Rust, first appeared in California in 
 San Mateo County in 1952, has prohib- 
 ited the production of Imperial Valley 
 varieties in that area. 
 
 Pasmo, which rarely causes appre- 
 ciable damage, produces lesions like 
 anthracnose. 
 
 Browning may cause lesions like 
 those of anthracnose, or it may cause 
 stem-break, the breaking of the stem just 
 above the soil surface. 
 
 Note : Anthracnose occurred in the San 
 Joaquin Valley in 1940-41, the other 
 four are flax diseases found in San Mateo 
 County. 
 
 Insect control 
 
 Flax is attacked occasionally by insects 
 that trouble other crops. The previous 
 crop history or adjacent crops may have 
 an important bearing on the incidence 
 of these pests. 
 
 Cutworms may become a serious 
 problem in young flax following alfalfa, 
 or in weedy, trashy fields. 
 
 Bait: 80 per cent bran, 11 per cent oil, 
 and 8 to 9 per cent of 25 per cent emul- 
 sifiable DDT, at 15 to 20 pounds per 
 acre. 
 
 Dust: 10 per cent toxaphene at 30 
 pounds per acre by ground rig, and 30 
 to 35 pounds by airplane. 10 per cent 
 
 With new chemicals becoming 
 available, and new formulations of 
 old ones, the recommendations 
 given in this circular may change. 
 Your Farm Advisor will have the 
 latest information on pest control. 
 
 [19] 
 
DDT at 20 to 25 pounds per acre by 
 ground rig, and 25 to 30 pounds by air- 
 plane. 
 
 Spray: toxaphene at 3 pounds per acre 
 by ground rig, and 3 to 4 pounds by 
 airplane. DDT at 1% pounds per acre by 
 ground rig, and 2 pounds per airplane. 
 
 Note: Ground application and spray 
 preferred. Irrigation water frequently 
 drives worms to surface when a DDT or 
 toxaphene spray may be more effective. 
 
 Salt marsh caterpillars (wooly 
 worms) migrating from cotton fields to 
 adajcent flax fields can be particularly 
 destructive to young stands of flax. The 
 foraging of a single caterpillar can per- 
 manently destroy all the plants in a foot 
 or two of a row in a matter of a few 
 hours when plants are in the early seed- 
 ling stage. 
 
 Bait: .516 pounds technical chlordane 
 to 100 pounds of bran. 
 
 Paper or aluminum foil barrier is put 
 around the field. Its effectiveness is in- 
 creased by sprinkling a 2 per cent BHC 
 dust outside the barrier at 5 pounds per 
 100 feet. 
 
 Beet army worms are destructive to 
 growing tips of flax seedlings and to the 
 inflorescences and bolls in later stages 
 of growth. 
 
 Control: (also for the darkling ground 
 beetle) 
 
 Dust: 5 per cent DDT at 15 to 20 
 pounds per acre by ground rig, and 25 
 to 30 pounds by airplane. 
 
 Spray: DDT at 1 pound per acre by 
 ground rig, and l 1 /^ to 1% pounds by 
 airplane. 
 
 Note: Ground application preferred 
 for darkling ground beetle. 
 
 Thrips have been observed in flax 
 fields for many years. Thrip populations 
 have shown a tendency to reach a peak 
 coinciding with the full bloom period of 
 flax. Considerable floral blast and failure 
 of buds to reach maturity may be attrib- 
 utable to thrips. They feed by a rasping 
 action generally on the tender parts of 
 the plant and especially concentrate on 
 the structures of the flowers and buds. 
 Although it has been impossible to meas- 
 ure the extent of damage caused by 
 thrips, it is believed to be of economic 
 importance each year. A feasible control 
 of thrips in flax fields has not been 
 worked out. 
 
 Crickets may occasionally be numer- 
 ous enough in seedling flax to require 
 control. 
 
 Bait: 1 pound of 62 per cent technical 
 chlordane to 1 gallon of deodorized kero- 
 sene, or its equivalent, and 100 pounds 
 of bran, applied broadcast at 10 to 20 
 pounds per acre. May be applied to bor- 
 ders and the field irrigated to drive the 
 crickets to the bait. 
 
 Spray: Actual aldrin or dieldrin at 2 
 ounces per acre, chlordane at 1 pound 
 per acre, or heptachlor at 6 ounces per 
 
 acre. 
 
 Harvesting and marketing 
 
 Flax is usually harvested by direct 
 combining. This may require that the 
 flax stand for a rather long period if 
 summer weeds are present. Where weeds 
 are not a problem, combining should be 
 done after 90 per cent of the bolls have 
 turned brown. Most flax is combined 
 directly. 
 
 Some flax is windrowed, and threshed 
 with a combine equipped with a pick-up 
 
 attachment. Windrowing is the accepted 
 method if a very heavy stand of summer 
 weeds develop in the maturing flax. It 
 should be done before the plants become 
 dry and brittle. Windrowing usually re- 
 sults in greater seed losses than direct 
 combining. 
 
 Most machines have angle-bar or rasp- 
 bar cylinders which revolve at a periph- 
 eral speed of 5,000 to 6,000 feet per 
 
 [20] 
 
minute. Concave-cylinder clearances 
 should vary from % 6 to ^4 inch; the 
 wider spacing is preferred if it removes 
 the seed from the flax bolls. Flax rolls 
 are mounted ahead of the cylinder, one 
 of these being steel and the other steel 
 with a hard rubber surface. The rolls 
 rotate at a peripheral speed of 300 to 400 
 feet per minute, one roll being set to 
 rotate about 10 per cent faster than the 
 other, to give a rubbing action on the 
 flax bolls. The rolls have led to much 
 more efficient threshing of flax; more 
 seed is recovered, and seed injury is less- 
 ened. Peg-tooth cylinders may break the 
 flax straw into small pieces which are 
 difficult to remove from the seed. 
 
 Screen size and wind velocities are re- 
 duced from those for small grain. Com- 
 bine adjustments may be necessary from 
 time to time depending on temperatures, 
 relative humidities and the condition of 
 the flax. The skill of the operator is an 
 important factor in efficient harvesting 
 of flax. 
 
 Static electricity sometimes is a prob- 
 lem in harvesting flax. This condition 
 may develop when temperatures exceed 
 100° F. and humidities are very low. 
 Seeds tend to cling to one another and to 
 the combine, screens become clogged, 
 and serious seed loss may occur. This 
 situation cannot be controlled; the only 
 alternative is to delay harvest until the 
 humidity increases slightly or until tem- 
 peratures are low enough to prevent its 
 occurrence. 
 
 Flax as it comes from the combine 
 contains some (and occasionally large 
 amounts of) dockage — weed seeds, other 
 grain, short pieces of straw, and chaff. 
 The dockage that most affects the grade 
 
 Top: Harvesting weedy flax in Imperial Valley 
 by direct combining. Note that the large wild 
 sunflowers are removed from the standing flax 
 ahead of the combine. Center: Harvesting a 
 clean field of flax by direct combining. Bottom: 
 threshing flax from the windrow. Flax is wind- 
 rowed prior to threshing when green weeds are 
 present in the ripe flax. 
 
 ■Mm 
 
are green weed seeds. If abundant they 
 may raise the moisture content suffi- 
 ciently to damage some of the flax. The 
 grower receives no compensation for the 
 dockage, but must pay the cost of ship- 
 ping it to the processor. 
 
 Most flax in Imperial Valley is har- 
 vested with a moisture content below 6 
 per cent which is low enough for safe 
 storage. The flaxseed may heat under 
 Imperial Valley temperatures if the mois- 
 ture content is above 8 per cent. 
 
 Markets for seed 
 
 Practically the entire flaxseed produc- 
 tion of the Imperial Valley is handled in 
 
 bulk and shipped by train to the Los 
 Angeles area where it is marketed and 
 processed. Much of the flax is marketed 
 through a local grower-owned and oper- 
 ated organization. A small amount of the 
 Imperial Valley flax is shipped to the San 
 Francisco Bay area. Some is exported, 
 the amount depending upon the world 
 price. 
 
 Because of the high cost of freight it 
 has not been feasible to supplement the 
 California production with flaxseed 
 grown in the Northern Great Plains. No 
 flax has been brought into California 
 from other countries because of import 
 duties. 
 
 Products from the flax plant 
 
 Linseed oil 
 
 The oil from flaxseed, linseed oil, is 
 used for a variety of products. Most of it 
 goes into the paint and varnish industry. 
 The oil after appropriate treatments or 
 additives dries quickly into a tough film. 
 It is also used in products such as lino- 
 leum, oil cloth, molds for castings, and 
 printer's ink. The oil is not used for food, 
 partly because the oil tends to develop 
 undesirable flavors rather quickly after 
 processing. 
 
 Flaxseed may contain from 32 to 44 
 per cent oil. In Imperial Valley the oil 
 content is high, ranging from about 39 
 per cent to over 43 per cent. (See table, 
 below.) Varieties may differ slightly 
 in the amount of oil they contain, Im- 
 perial having less than Punjab 47 and 
 Punjab 53 (table on page 6). New 
 River has a higher oil content than any 
 of the varieties grown commercially in 
 California. Where flax is not irrigated 
 sufficiently and suffers from lack of mois- 
 
 Oil Analysis of Shipments of Flax from Imperial Valley, 
 Averages 1949-55* 
 
 Time of year 
 
 Oil content 
 
 Iodine value 
 
 Year 
 
 Oil content 
 
 Iodine value 
 
 June 14 
 
 June 21 
 
 per centf 
 
 41.9 
 41.8 
 41.3 
 41.6 
 41.5 
 41.1 
 41.1 
 41.1 
 
 185 
 185 
 184 
 182 
 183 
 182 
 182 
 183 
 
 1949 
 1950 
 1951 
 1952 
 1953 
 1954 
 1955 
 
 per centf 
 
 40 8 
 40.4 
 43 2 
 42.3 
 41.2 
 40.6 
 40 9 
 
 179 
 
 182 
 
 June 28 
 
 184 
 
 July 5 
 
 July 12 
 
 185 
 187 
 
 July 19 
 
 181 
 
 July 26 
 
 187 
 
 August 2 
 
 
 
 
 * Data supplied by the Southwest Flaxseed Association, Imperial, California. 
 f On basis of actual moisture content. 
 
 [22] 
 
ture as the seed develops, the seed is 
 shrunken and low in oil. The high oil 
 content of Imperial Valley flax is in part 
 a reflection of its low moisture content 
 which ranges from 5 to 6 per cent, in 
 contrast to 8 to 10 per cent from the 
 Northern Great Plains. 
 
 Oil content of commercial shipments 
 appears to vary slightly from year to 
 year (see table, page 22). On the basis 
 of averages for a seven-year period, there 
 is very little reduction in oil content of 
 flax shipments from the Imperial Valley 
 during the period from June 1 to 
 August 1. 
 
 Iodine value or iodine number is an 
 index of the value of linsed oil for use in 
 paints and varnishes. The range of iodine 
 value lies between 140 and 205 in ex- 
 treme cases, but usually between 170 and 
 190. As with oil content, iodine value 
 varies with different varieties and with 
 different environments. In Imperial Val- 
 ley it has rarely been lower than the 
 normal commercial requirement of 177. 
 
 Most of the linseed oil produced in 
 California is consumed in the state; only 
 very small amounts are shipped to neigh- 
 boring states. Under certain marketing 
 arrangements the U. S. Department of 
 Agriculture has moved some linseed oil 
 
 from California onto the export market 
 to reduce national surpluses. Small 
 amounts of linseed oil come into Cali- 
 fornia from the Northern Great Plains. 
 
 Linseed meal 
 
 The crude protein content of the meal 
 or cake varies from 30 to 35 per cent, 
 and usually averages around 34 per cent. 
 The amount of oil in the meal depends 
 on the method of processing, being 5 to 
 7 per cent if processed with a press or 
 expeller, and 1 to 3 per cent if processed 
 with solvents. The meal is popular with 
 livestock feeders not only because of the 
 high protein content, but also because of 
 its good palatability and slight laxative 
 effect. 
 
 Feed value of flax straw 
 
 Flax straw is rarely fed to livestock. If 
 mature and of good quality, it is about 
 equal to oat or barley straw in feed value. 
 It can be used safely as the only rough- 
 age for cattle. The fibers are digested 
 like other fibrous materials and do not 
 accumulate in the stomach to form indi- 
 gestible balls. 
 
 Be careful about feeding flax straw 
 that has considerable green material in 
 it because immature flax may contain 
 
 Feed Value of Flax Straw and Linseed Meal with Comparisons* 
 
 
 Total 
 
 dry 
 
 matter 
 
 Average total composition 
 
 Digestible 
 protein 
 
 Total 
 
 
 Protein 
 
 Fat 
 
 Fiber 
 
 N-free 
 extract 
 
 Mineral 
 matter 
 
 digestible 
 nutrients 
 
 Flax straw 
 
 Oat straw 
 
 Barley straw . . . 
 Linseed meal 
 
 (o.p.)t 
 
 Linseed meal 
 
 (s.p)t 
 
 Cottonseed 
 mealf 
 
 per cent 
 
 92.8 
 
 89 8 
 
 90 
 
 91.0 
 90.1 
 92.8 
 
 per cent 
 
 7.2 
 4.1 
 
 3.7 
 
 35 1 
 
 36 6 
 43 3 
 
 per cent 
 
 3.2 
 2.2 
 1.6 
 
 4.5 
 
 1.0 
 
 5.1 
 
 per cent 
 
 42.5 
 36 3 
 37.7 
 
 9.0 
 
 9.3 
 
 11.0 
 
 per cent 
 
 32 9 
 40 9 
 41.0 
 
 36 7 
 
 38 3 
 
 27.4 
 
 per cent 
 
 7.0 
 6 3 
 6 
 
 5 7 
 
 5.8 
 
 6 
 
 per cent 
 
 5.8 
 7 
 0.7 
 
 30 5 
 
 30.7 
 
 35 9 
 
 per cent 
 
 38.1 
 44.8 
 42.2 
 
 75 3 
 
 70 3 
 
 72 6 
 
 * Morrison, F. B. Feeds and Feeding. Morrison Publishing Co., Ithaca, N.Y. 1956. 
 t o.p. — old process, using hydraulic press or expellers; s.p. — solvent process. 
 | 43 per cent protein grade. 
 
 [23] 
 
poisonous amounts of prussic acid. The 
 danger is greater if the immature flax is 
 frozen. Volunteer flax appearing after 
 harvest may be unsafe as pasture. 
 
 Seed flax straw — 
 a source of fiber 
 
 Large amounts of straw of seed flax 
 are processed each year in the United 
 States to obtain the fiber. One processing 
 plant is located in the Imperial Valley. 
 The yield of straw from seedflax is 
 around % to % ton per acre. The fiber 
 content is about 10 per cent of the straw 
 weight. 
 
 The company processing the straw for 
 fiber in Imperial Valley takes the straw 
 from the best fields only — those which 
 have a dense and uniform stand of flax, 
 and are free from weeds. Grasses are the 
 most troublesome weeds because it is 
 difficult to separate the grass straw from 
 the flax fibers during processing. After 
 harvesting the flax for seed, the straw is 
 raked into windrows. If the combine had 
 been set very high, it may be necessary 
 to mow the field prior to raking. Enough 
 straw is baled and piled near the proc- 
 essing plant to keep it in operation for 
 an entire year. The price for the deliv- 
 ered straw varies between $13.00 and 
 $15.00 per ton. 
 
 Processing equipment consists of a 
 combination of corrugated rollers that 
 
 break and crush the woody stems, and 
 shakers that separate the broken woody 
 portions from the long tangled fibers. 
 The fiber is baled and shipped to a paper 
 mill in North Carolina. There the fiber 
 is manufactured into high-grade types 
 of paper such as cigarette paper, Bible 
 paper, carbon paper, and air-mail bonds. 
 
 Fiber flax 
 
 Linen, one of the finest of fabrics, is 
 made from flax developed for that pur- 
 pose. Such flax has long fine stems that 
 produce a high-quality fiber. 
 
 A fiber-flax industry is not feasible in 
 Imperial Valley because the extraction 
 of fiber requires more hand labor and 
 time than is justified by the returns. The 
 yield of fiber probably would not exceed 
 400 pounds per acre, with the price being 
 not much above 40^ per pound. 
 
 The flax plants must be pulled by hand 
 or by machines especially designed for 
 this purpose. The pulled plants are tied 
 into sheaves, and allowed to dry. Then 
 the sheaves are soaked in a tank of water 
 until the non-fibrous portions of the stem 
 have "retted" — rotted in part. The retted 
 sheaves are dried and stored for proc- 
 essing. Processing is similar to that de- 
 scribed for the extraction of fiber from 
 seed flax, except that all the fibers must 
 be kept parallel and must not be per- 
 mitted to tangle. 
 
 Production costs 
 
 Costs of producing flax in Imperial 
 Valley, as detailed below, are about 
 $30.00 per acre higher than they are for 
 barley. Minimum costs would be about 
 $75.00 per acre. With the price of flax 
 
 ranging between $3.00 and , $4.00 per 
 bushel, it is understandable why many 
 farmers feel that they cannot afford to 
 grow flax unless they obtain at least 30 
 to 40 bushels per acre. 
 
 [24 
 
Costs of Production 
 
 Items 
 
 Land preparation — labor and field power : 
 
 Disc, border, disc, float, fertilize, irrigate, mulch, etc 
 
 Cultural labor and field power : 
 
 Planting across borders 
 
 Fertilizing 
 
 Irrigating — 7 times 
 
 Weed control 
 
 Border and ditch work 
 
 Miscellaneous 
 
 Total 
 
 Materials : 
 
 Irrigation water — 2.5 feet 
 
 Seed— 42 lbs. at 13^ 
 
 Fertilizer— 120 lb. N, and 80 lb. P 2 5 
 
 Total 
 
 Harvesting : 
 
 Combining in bulk 
 
 Hauling 
 
 Shipping costs to Los Angeles 
 
 Total 
 
 Cash overhead : 
 
 General expenses (5 per cent) 
 
 Taxes 
 
 Repairs 
 
 Insurance 
 
 Total 
 
 Depreciation 
 
 Land rent 
 
 Total costs : 
 
 Less returns for straw 
 
 Total . . 
 
 * Data from the Agricultural Extension Service, Imperial County, 1956 
 t Based on a yield of 35 bushels per acre. 
 
 Costs 
 
 Per acre 
 
 Per bushel f 
 
 $10 50 
 
 2 00 
 
 2 00 
 4 20 
 
 3 25 
 2 00 
 2.00 
 
 15.45 
 
 5 00 
 
 5 00 
 
 26.00 
 
 36 00 
 
 9 00 
 2.00 
 5.10 
 
 16.10 
 
 113.85 
 
 $0 30 
 
 44 
 
 1 03 
 
 46 
 
 3 90 
 
 
 2 00 
 
 
 1.00 
 
 
 40 
 
 
 7 30 
 
 21 
 
 2.50 
 
 07 
 
 30 00 
 
 86 
 
 117.85 
 
 3 37 
 
 4 00 
 
 0.11 
 
 3 26 
 
 [25] 
 
Goals for research 
 
 Flax research in California is con- 
 ducted by many departments within the 
 University of California and the United 
 States Department of Agriculture, in- 
 cluding the Imperial Valley Field Sta- 
 tion, the Southwestern Irrigation Field 
 Station, the Agricultural Extension Serv- 
 ice of Imperial County, and the Univer- 
 sity at Davis and Riverside. In most 
 instances the research is cooperative 
 among personnel of the various agencies, 
 and often research information from 
 other states, such as Minnesota and 
 North Dakota, is utilized. Here is a list 
 of current research projects that will 
 benefit flax production in Imperial 
 Valley: 
 
 Development of improved varie- 
 ties: Resistance to Fusarium wilt greater 
 than that of Punjab 53 and New River is 
 being added to the varieties Punjab 47 
 and Imperial. A search is being made 
 for resistance to curly top and Rhizoc- 
 tonia wilt. 
 
 Inheritance studies: Studies are 
 under way on the inheritance of such 
 items as resistance to Fusarium wilt, re- 
 sistance to rust, oil content and quality, 
 and tolerance to 2,4-D. Such studies put 
 plant breeding on a more precise or sci- 
 entific basis. 
 
 Culture: Some research is being done 
 on the fertilizer and irrigation require- 
 ments of flax, but more is necessary. Un- 
 fortunately results from such research 
 are often applicable only in the field or 
 area where the research is done. 
 
 Pest control by chemicals: Con- 
 stant experimentation is necessary to 
 keep abreast of developments in herbi- 
 cides, insecticides and fungicides. 
 
 Improvement in linseed oil: Re- 
 search in this field will permit linseed 
 oil to compete more effectively with other 
 vegetable oils of commerce. It is hoped 
 that flax varieties may be found that will 
 provide widely different types of linseed 
 oil. 
 
 California ranks low in the United States as a flax-producing state, but seed yields 
 per acre greatly exceed those of other states as shown in the table below: 
 
 Comparison of U. S. Flaxseed Producing States, 1945-1954* 
 
 
 Acreage 
 harvested 
 
 Yield 
 
 Production 
 
 Price per bu 
 
 North Dakota 
 
 1,000s 
 
 1,869 
 1,218 
 610 
 136 
 105 
 94 
 158 
 
 bu/Af 
 
 7 9 
 10 2 
 
 8 6 
 6 7 
 6 2 
 
 23 
 11.7 
 
 1,000 bu 
 
 14,780 
 
 12,377 
 
 5,233 
 
 911 
 
 650 
 
 2,164 
 
 1,844 
 
 $3 98 
 
 Minnesota 
 
 South Dakota 
 
 4 00 
 3 97 
 
 Texas 
 
 Montana 
 
 California 
 
 Other states 
 
 3 74 
 3 86 
 
 4.42 
 
 
 
 Total 
 
 4,190 
 
 9.0 
 
 37,959 
 
 3 99 
 
 * USD A Agricultural Statistics. 
 
 t The bushel weight for flax is 56 pounds 
 
 [26] 
 
Scientific names 
 
 Weeds 
 
 Wild oats Avena jatua 
 
 Canary grass Phalaris minor 
 
 Wild mustard Brassica kaber 
 
 Field mustard Brassica campestris 
 
 Sour clover Melilotus indica 
 
 Hubam clover Melilotus alba annua 
 
 Redweed Polygonum argyrocoleon 
 
 Indian mustard Sysimbrium irio 
 
 5-hook bassia Bassia nysspoijolia 
 
 Nettle-leafed goosefoot 
 
 Chenopodium murale 
 
 Lambsquarter Chenopodium album 
 
 Pigweed Amaranthus powellii 
 
 Wild sunflower Helianthus annuus 
 
 Wild beets .Beta maritima 
 
 Water grass Echinocloa crusgalli 
 
 Insects 
 
 Cutworms Family Noctuidae 
 
 Beet armyworm 
 
 Laphygme exigua (Hbn.) 
 Darkling ground beetles 
 
 Family Tenebrionidae 
 
 Crickets Family Gryllidae 
 
 Beet leafhopper 
 
 Circulifer tenellus (Baker) 
 Salt marsh caterpillar 
 
 Estigmene acraea (Drury) 
 Thrips Frankliniella sp. 
 
 Diseases 
 
 Wilt Fusarium oxysporum f. lini 
 
 Seedling blight Rhizoctonia solani 
 
 Anthracnose Colletotrichum lini 
 
 Botrytis blight Botrytis cinerea 
 
 Rust Melampsora lini 
 
 Pasmo Sphaerella linorum 
 
 Browning Polyspora lini 
 
 In order that the information in our publications may be more intelligible, it is sometimes 
 necessary to use trade names of products and equipment rather than complicated descriptive or 
 chemical identifications. In so doing, it is unavoidable in some cases that similar products which 
 are on the market under other trade names may not be cited. No endorsement of named prod- 
 ucts is intended nor is criticism implied of similar products which are not mentioned. 
 
 Co-operative Extension work in Agriculture and Home Economics, College of Agriculture, University of California, and United States Department of Agriculture 
 co-operating Distributed in furtherance of the Acts of Congress of May 8, and June 30, 1914. George B. Alcorn, Director, California Agricultural Extension Service. 
 
 7*m-7,'59(A759)JF 
 
 [27] 
 
AGRONOMY TRAINING 
 
 leads to many careers 
 
 AGRICULTURAL INDUSTRIES 
 
 RESEARCH ORGANIZATIONS 
 
 GOVERNMENT AGENCIES 
 
 FARMING 
 
 Agronomy deals with the production and 
 improvement of field crops, pastures, and 
 rangelands. 
 
 Agronomic crops are grown on more than 
 half of California's agricultural land. 
 
 Trained agronomists are needed to 
 produce more foodstuffs, 
 handle speciality crops, 
 develop improved varieties, 
 devise and apply scientific methods. 
 
 Training at Davis has special advantages: 
 Instructors who are leaders in their fields, 
 and are active in research on today's farm 
 problems. 
 
 The University farm, for practice and ex- 
 periment in one of the nation's richest farm 
 areas. 
 
 Modern facilities, for better study and re- 
 search. 
 
 An uncrowded campus, with many new 
 buildings. 
 
 Letters and Science college on the same 
 campus, broadening the scope of education. 
 
 FOR FURTHER INFORMATION 
 
 on agronomy write to Maurice L. Peterson, 
 opportunities chairman, agronomy depart- 
 ment. 
 
 on entrance write to Howard B. Shontz, 
 requirements office of the registrar. 
 
 on college see your County Farm Ad- 
 opportunities visor for college entrance 
 counsel. 
 
 University of California * Davis, Calif. 
 
 CAREERS IN 
 
 farm management 
 
 farm operation 
 
 seed processing 
 
 seed marketing 
 
 agricultural industry 
 
 farm supply houses 
 
 farm service houses 
 
 teaching 
 
 research 
 
 Agricultural Extension 
 
 Service 
 
 crop improvement 
 
 associations 
 
 departments of agriculture 
 
 STUDY INCLUDES 
 
 management 
 
 adaptation 
 
 plant breeding 
 
 culture 
 
 utilization 
 
 processing of cereals 
 
 oil crops 
 
 cotton 
 
 sugar beets 
 
 beans 
 
 hay crops 
 
 range plants 
 
 irrigated pastures 
 
 distribution 
 
 variety improvement 
 
 soil management 
 
 weed control 
 
 crop diseases 
 
 animal husbandry 
 
 agricultural machinery