IN TEXAS TEXAS AGRICULTURAL EXPERIMENT STATION - - - TEXAS AGRICULTURAL EXTENSIUN SERVICE College Station, Texas IN COOPERATION WITH THE UNITED STATES DEPARTMENT OF AGRICULTURE The Plant ............................................................................... .. Uses of Castorbeans .............................................................. .. Adaptation ............................................................................ .. Varieties for Texas ....................... ......................................... .. Cultural Practices .................................................................... .. mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmu Seedbed Preparation ........................................................ .. Planting ............................................................................ .. c 0 N T E N T S Fertilizer Requirements .................................................... .. lrrigation .......................................................................... .. Weed Control .................................................................... .. lnsects anol Diseases .............................................................. .. Harvesting .............................................................................. .. Costs anol Returns .................................................................. .. l Cropping Sequences .............................................................. .. l Caufion .................................................................................. ..l Mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmummmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm iw- became established as a competi- crop for farmers of the Texas High ring the late 1950’s, after develop- high-yielding dwarf varieties and harvester-hullers. Acreage expanded jfew hundred acres in 1957 to over . "1959, with strong indications that ywould be greatly expanded in this Qthe immediate future. is a large and increasing demand for for industrial purposes; the United p presently the largest importer and of castor oil, taking 35 to 45 per- ilihe total world production. Domestic nsupplied only 10 to 18 percent of ted States consumption during the Texas became the leading state in n production in 1959. are produced in Texas for the its‘ contain approximately 50 percent mills or processing plants are located te, and all castorbeans produced are iYby rail to a large plant in Bayonne, Tsey, for crushing. Other plants are éin the Los Angeles and San Francisco igfpthese plants currently crush castor- YOduced in New Mexico, Arizona and r} ' a.» ' . ercial production of castorbeans the central part of the United States » as 1850, but sporadic production ills eventually to locate on the east i‘ coasts to crush imported castorbeans. ars I and II stimulated attempts to our own domestic supply of castor- ce the oil was classed as critical ma- <§During the Korean conflict, renewed esulted in increased production, and Silas one of the chief states producing p1 ns for the government-sponsored program. Commercial production Psince 1955 has centered around Plain- rere a private company maintains a l; point and personnel to assist farmers jcing castorbeans. Another company ntracting acreage in early 1960. All acreage in this area is irrigated. rflely, research agronomist, Crops Research Agricultural Research Service, United States ent of Agriculture; and extension agron- iiTexas Agricultural Extension Service, The & M. College System. Castorbeans in Texas Raymond D. Brigham and Ben R. Spears* THE PLANT The term “castorbean” is used commonly to refer to both the plant and seed of Rzcmus communis L., a member of the Euphorbiaceae, or spurge,_family. It is not a legume as the name implies. Castorbean also has been called “Palma Christi,” or mole bean. Castor oil, one of the oldest commercial products, was used in lamps by the Egyptians more than 4,000 years ago, and castorbeans have been found in their ancient tombs. Castorbeans, considered by most authorities to be native to tropical Africa, may have originated in Abyssinia. Castorbean plants are potential trees. They grow perennially in the tropics and sub- O ° Immature racemes \" o ,) i1 d s" O l ‘(F/ O ° l F O O0 I l 0° . ° ° l‘ ° ° Ternary racemes o o 0° . O 0 Q thlrd set- 'Yo "\\ ,// O Secondary racemes O ~ . second set-mature 0 , Q . Q ---- Primary raceme, or spike 0 first set—mafure O Seed capsule ' O fi \ ...._.. Petioles, or leaf stems Infernode Node I I l JZV. Fig. I. Defoliated castorbean plant (schematic drawing). 3 t Fig. 2. Mature castorbean raceme (spike). Three seeds usually are contained in each capsule, but two to four may occur. tropics to heights of 30 to 40 feet. However, castorbeans behave as an annual in the tem- perate areas of the World where frost kills the plant. The dwarf-internode commercial types grown in Texas vary in height from 3 to 5 feet; the normal-internode types formerly grown commercially were 6 to 12 feet tall. Soil conditions may cause much variation in height within varieties. Castorbeans have a tap root, but prominent lateral roots are pres- ent a few inches below the soil surface. The large leaves, palmately lobed similar to cotton, are born more or less alternately on the stems, except for two opposite leaves at the node just above the two cotyledonary leaves. The petioles, or leafstalks, which attach the leaf to the stem, usually are several times as long as the long axis of the leaves. The main stem is terminated by the first raceme (com- monly called a “spike”) which often is the largest on the plant. The first (or primary) raceme of early dwarf-internode varieties grown in Texas usually occurs after the sixth to tenth nodes. On later varieties, the first raceme may occur after the eighth to six- teenth nodes. In introductions from other countries, dwarf-internode types flowering after 40 or more nodes are known. After the first raceme appears, branches originate at the nodes below it, Figure 1. The number of branches depends on plant spacing and in some cases on the variety. Under field conditions, two or three branches occur at almost the same time, but generally in the fol- 4 lowing order: the first branch at the node immediately beneath the primary raceme; the second at the second node; and the third at the third node below the primary raceme. Each of these branches, usually after four or five nodes have formed, ends in a raceme. The § first racemes formed on the branches are l commonly called the “second set” of racemes. Subsequent branches arise from the nodes just beneath the racemes of thenslecond set. This sequence of development continues as long as i the plant remains alive and growing actively. Thus, the development of racemes along any one axis is sequential, making it possible for ,1 a plant to have racemes in all stages of de-_ velopment from bud stage to complete ma?) turity. In a typical plant (and present vari- l eties are of this type), the racemes usually bear female flowers on the upper 30 to 50 per- a cent and male flowers on the lower 70 to 50! percent of the raceme. Commercial hybrid varieties, when available, may be of this type. l Other promising hybrids may bear only fe- male flowers along the entire raceme, but planting seed of these hybrids will contain a small percentage that will produce sufficient pollen-shedding plants to insure seed set of the pistillate plants in the commercial field. Number and proportion of male to female flowers can vary greatly. The flowers, both male and female, are without petals. After“ the pollen is shed, the male flowers dry up and usually drop. The pollen, which is discharged forcibly from the anthers, is carried to the stigmas of the female flowers mainly by wind. Fig. 3. Top left, dry filled capsules; top right, segmen (carpels) of a capsule that contain the seed; bottom left clean seed; bottom right, hulls from capsule. ’ ilization, the female flowers devel- ‘piny capsules, though spineless types ' At maturity, the hull (pericarp) psule may split along the outside _rsal suture) of each of the three cap- ents- (carpels). If the splitting is ias in wild types, the seed will be d scattered on the ground around This type of splitting (dehiscence) esent in the commercial varieties r mechanized production; seed of arieties are held within the capsule l weeks after frost with no appreci- f current varieties grown in Texas ize from 1,400 to 1,600 per pound. ranges from light to dark brown, ous mottling patterns. The seed coat gabout 25 percent of the weight of the - content averages 50 percent, on a 1S. VF CASTORBEANS .10il is used in ever-increasing quan- g chemurgic raw material. Its largest A is by the protective coatings indus- J1 produces paints, varnishes and lac- iery small quantities are used in the most castor oil undergoes one or f.“ processes to adapt it to a par- Table 1. More than 175 deriva- ‘ tor oil are offered by one company. esidue remaining after the oil has _ cted from the seed is known as castor find-is used widely as organic fertil- ‘use is restricted largely to areas of jjj» west coasts. Because a poisonous t, ricin, remains in the pomace after j, of the oil, the pomace cannot be ivestock feed. Processes are known ying the toxic nature of ricin, but firresently economical for commercial TION igh Plains area appears to be well ,r growing castorbeans. Highest f? produced under irrigation on fine (-textured soils. Most of the soils Plains are in three general groups: extured soils (Pullman silty clay p; related soils, commonly called “hard ffthe medium-textured soils (mostly ‘and Portales sandy loams, commonly ixed lands”) and the coarse-textured ,a._s Brownfield sands, commonly ‘litly lands”). _ ta 140-day growing season is re- __rom planting until first killing frost) ice satisfactory yields in the High Table 1. Uses of and products resulting from proc- essing castorbeans and castor oil Adhesives Alkyds Artificial leather Asphalt tile Bactericides Belt dressings Brake fluids Brake linings Candles Carbon paper Castor oil Caulking compounds Coated fabrics Condenser oils Corrosion inhibitors Cosmetics Crayons Cutting oils Dielectric compounds Drawing compounds Duplicating stencils Emulsion paints Emulsion polishes Enamels Leather dressings & coatings Lubricating oil additives Linoleum Motor fuel additives Nylon Oil cloth Packin gs Paints Paper coatings Perfume intermediates Pharmaceuticals Pigment grinding compounds Pigment suspension compounds Plastisols Polishes Plasticizers Polyesters Potting compounds Putties Rubber accelerators Rubber compounds Fertilizers Rust inhibitors Fertilizer fillers Shock absorber fluids Fungicides Soap preparations Gasket pastes Strippable coatings Germicides Textile processing Greases compounds Hydraulic fluids Urethane foams Inks, duplicating Varnishes Inks, printing Vinyl compounds Insecticides Waxes Lacquers Plains area, and a 150 to 160-day season is more desirable. Castorbeans are adapted to most other areas of Texas where cotton is grown, and where rainfall or irrigation water is adequate, but diseases are limiting factors where high relative humidities prevail. Areas where soils are infested with the cotton root-rot fungus should not be considered for growing castor- beans, because the plants are highly susceptible to this disease. VARIETIES FOR TEXAS Dwarf-internode varieties have been grown almost exclusively for commercial production since 1957. These varieties were developed especially for mechanical harvest. They grow only 3 to 4 feet tall and are highly resistant to seed shattering and capsule losses from wind. Resistance to wind is important, since castorbeans may stand in the field several weeks after a killing frost before they are harvested. Oil content of the available vari- eties averages 50 percent by weight. BAKER 296 is early maturing and pro- duces many small to medium racemes. It is extremely resistant to shattering, and mod- erately resistant to bacterial leaf spot. How- ever, it is very susceptible to Alternaria leaf 5 Fig. 4. Dwarf castorbean varieties are similar in height -t0 grain sorghum, and are well adapted to mechanical harvesting. spot, and is difficult to hull because of a thick capsule wall. Baker 296 comprised most 0f the acreage in 1958 and 1959. It yielded more than 3,000 pounds per acre in 1958 where moisture and fertilizer were optimum; yields over 2,000 pounds per acre were common. DAWN is a late-maturing variety that pro- duces a few large racemes. It is highly re- sistant to shattering, hulls easily, has resist- ance to Alternaria leaf spot and is moderately resistant to bacterial leaf spot. Yields of more than 2,700 pounds per acre have been produced under favorable conditions. Baker 296 is favored over Dawn in the Plainview area be- cause of its earlier maturity and less likelihood of frost damage before the seed mature. Sev- eral hundred acres of Dawn were grown in 1957 but an early frost seriously reduced yields; only small acreages of the variety were planted the following 2 years. Further field testing of the variety may show it has desirable characteristics under more favorable condi- tions. Plant breeders of commercial companies, the United States Department of Agriculture and state agricultural experiment stations strive cooperatively to develop improved vari- eties. Dwarf-internode hybrids appear prom- ising, but the only hybrids presently available in quantity are tall-growing types (normal- Table 2. Yields per ac_re_ of two dwarf-internode castorbean varieties grown for, 3 years in replicated yield trials at Plainview Pounds per acre‘ Variety 1957 1958 1959 Baker 296 2064 2438 1829 Dawn 1757 2376 2231 ‘Average of four replications 6 internode) which are grown commercially in California and Arizona. A commercially pro- a duced dwarf-internode hybrid was planted on a small acreage in 1960. CULTURAL PRACTICES Seedbed Preparation. Seedbed preparation is much the same as for cotton. Deep tillage, i such as chiseling 8 to 12 inches deep, encour- a ages development and deeper}; penetration of the tap root. Castorbeans usually are planted in a furrow by opening a bed with a lister-type a planter. Beds usually are irrigated before planting by running water down the furrows- Castorbean land should be prepared for inch rows, since most harvesters used in Texas are made for that row spacing. Planting. 60 degrees Fahrenheit at 8-inch depth at 8. a.m. This usually coincides with cotton plant- ing time on the High Plains. Cool nights in late April and early May tend to keep soil tem- ; peratures too low for satisfactory germination,- but May 5 to 25 usually is satisfactory for planting in the Plainview area. Castorbeans should not be planted after June 10 in that area. Only seed of high germination and of good quality should be planted, since poor seed oftenf produce poor stands or weak seedlings. Test weight, color, plumpness and lack of cracks in the seed coat are evidence of seed quality. a Arasan or Captan, at the rate of 1 to 2 ounces per bushel, is satisfactory for seed treatment. A planting furrow 3 to 4 inches deep nor- mally permits the seed to be in contact with moist, firm soil when planting after a pre- planting irrigation. Deeper planting furrows may delay emergence and increase the prob- ability of replanting after hard, washing rain- storms. Early varieties tend to set the first spike low, and this spike may not be harvested with the present mechanical harvesters if a deep planting furrow is used. Castorbean seed are large and slow to germinate; emergence - of the seedlings may take 7 to 14 days, but more often it takes 10 days. For uniform germination and emergence, the seed require moist soil over a longer period than do corn or cotton seed. Castorbean seed should be planted 21/2 to 3 inches deep, depending on the texture and condition of the soil. If press wheels are used in contact with the seed, care should be taken that they do not crush the seed. Castorbeans should be planted in 40-inch rows, with a seeding rate of 12 to 14 pounds? per acre. A plant spacing of 8 to 10 inches within the row is considered satisfactory. Castorbeans should be planted when the soil is warm—a 10-day average of With careful planting, thinning is not neces- sary. Special care should be taken t0 prevent crushing the fragile castorbean seed in the planter box. An inclined-plate planter is ideal, but a cotton planter box can be used if properly modified. The seed pawl or leveler should be replaced by a wire or brush-type leveler, and the plate should have enough holes so that it will turn at a slow speed and still plant at the desired rate. Plates for current varieties should be 5/ 16-inch thick, with 9/ 16-inch round holes in the center-drop plates, or 9/ 16 by 1/ 4- inch cells in the edge-drop type. Oil and crushed seed may clog the plates and prevent the seed from dropping evenly. If this occurs, empty the the planting box and wash it with kerosene. A handful of corn meal or coarsely ground grain sorghum mixed with each hopper of seed will help prevent this problem. Fertilizer Requirements. Adequate amounts of nitrogen and phosphorus must be available to produce high yields of castorbeans. Most soils in the High Plains area are low in nitro- gen, and nitrogen fertilizer usually must be applied to produce good yields. To fertilize castorbeans properly, first determine the need for nitrogen and phosphorus by having the soil tested; then apply the kind and amount of fertilizer recommended in the soil test report. When a soil test and past cropping history show a field is deficient in nitrogen, 60 to 120 pounds of nitrogen usually are needed for maximum yields of castorbeans. It is possible to overfertilize with nitrogen, producing rank vegetative growth and weak root systems. For that reason, split applications of nitrogen are recommended. The second application can be made by sidedressing nitrogen between the rows at about the last cultivation, while avoid- ing root damage as much as possible. The application of phosphorus to soils low in this element will produce more vigorous plants, hasten maturity and generally increase seed set. On deficient soils, 20 to 60 pounds of available phosphoric acid (P205) may be needed, and can be applied before or at planting time. Soils of the High Plains generally are well supplied with potassium. Irrigation. Preplanting furrow irrigation should wet the soil profile to caliche on shallow soils or to a depth of 5 or 6 feet on deep soils to supply subsoil moisture for castorbean plants throughout the growing season. Except on sandy soils, wetting the soil more than 3 feet during the growing season is not practical. Adequate preplantiigg""irrigation insures suffi- cient subsoil moisture during peak periods of water use. Excessive irrigation of heavy soils during the growing season results in damage from “water-logging” or poor soil aeration. Fig. 5. Inclined-plate planters, such as shown above, are ideal for planting castorbeans. However, modified cotton planters can be used. In years of normal rainfall, the first irriga- tion water usually is applied in late June or early July, just before the first raceme ap- pears on the plant. The peak water require- ment period usually is during late July and through August, when the plants are fruiting heavily. The top 2 feet of soil should be watched closely to determine the amount of useful soil moisture remaining. Irrigation is needed when approximately half the total available soil moisture has been used. A chart for estimating soil moisture is available from county agricultural agents. Irrigation should begin early enough that the last plants to be irrigated will not reach a moisture stress. The capacity of the well or delivery from other sources should be known to plan the watering schedule properly. Castorbeans have a high water requirement during critical periods, and the acreage grown should be limited to the amount that can be irrigated adequately. If low rainfall, high temperatures and high winds occur during the peak growing and fruiting period, irrigation may be required each 7 to 10 days to maintain high yield potentials. Under more normal conditions, 12 to 14 days between irrigations may be sufficient. If the leaves are allowed to wilt at any time during the morning, blasted or poorly filled seed cap- sules will result and some leaves will be lost as a result of the moisture stress. Castorbeans require approximately 20 to 24 acre-inches of water annually to produce high yields, depending on climatic variations. The time of last irrigation usually is from Septem- ber 1 to 10, according to the growing season. Weed Control. Castorbean seedlings emerge slowly, and annual weeds and grasses often are a problem until the plants make some growth and begin to shade the area between the rows. Cultivation is much the same as for controlling weeds in cotton. Rotary hoes often are used before or after the plants emerge to 7 control small annual weeds and grasses. Proper timing of this operation often can eliminate or reduce hand hoeing. Castorbean plants are tap-rooted, but they also have a shallow, wide-spread fibrous root system that appears to be much more impor- tant than the tap root in obtaining moisture and nutrients from the soil. For this reason, cultivations should be as shallow as possible, and only as often as necessary to control weed growth. During the last cultivation, front cultivator sweeps should not be set close to the plants in the row or the shallow lateral roots may be damaged. INSECTS AND DISEASES The castorbean plant is not toxic to most insects. Infestations of thrips, corn earworms, armyworms, spider mites, leaf miners, lygus bugs, green stink bugs and false chinch bugs sometimes appear in castorbean fields. Only infestations of the false chinch bug have be- come serious enough to warrant control meas- ures on the High Plains, and then only in scattered fields. Webworms, caterpillars, grasshoppers and leafhoppers also have been observed in castorbean fields. To date, insects have not been a serious problemon the High Plains. However, as the acreage increases and production extends over several years, popula- tions of certain insects may build up and make control measures necessary. Diseases usually are present on castorbeans in the High Plains area, but often do little damage, because the low relative humidity, together with sparse rainfall during a normal growing season, is generally unfavorable for their development. However, there are sev- eral diseases that can cause serious economic loss when conditions are optimum for their development. Proper cultural practices should be followed to produce vigorous plants, because they are more resistant to disease than weak plants. a Various soil and seedborne fungi can cause damping-off of young seedlings, but they can be controlled largely by fungicidal seed treat- ment. A seedling disease similar to sore shin of cotton occurred in 1960 when early planted castorbeans germinated and emerged in cold, wet soils. Later plantings in warmer soils were not affected. This appears to be a satis- factory control for this seedling disease. Alternaria leaf spot, caused by Alternaria rieini (Yoshii) Hansford, has resulted in varying degrees of defoliation of castorbeans on the High Plains. The leaf spot usually is visible first on the lower, older leaves of the plant as light-brown spots made up of con- centric rings around the point of infection. Diseased leaves dry and curl and drop pre- 8 .5 i? s § a i z i Fig. 6. Bacterial leaf spot of castorbeans can ca defoliation and lower yields. maturely. Losses in yield have ranged fro negligible to serious. Damage from Alternari leaf spot in 1958-59 was moderate to heavy i, fields of Baker 296, and the incidence of th. disease appeared to be connected with disease‘ damaged roots, which weakened the plants an made them more susceptible to leaf infections A capsule mold, caused by the same fungus occurs on the High Plains but usually is no a problem; however, it is very serious in area of high rainfall and high humidity. Capsule are attacked when half to full size, and ligh or unfilled seed often result when infectio occurs early in the development of the ca; sules. Capsules attacked early usually wil and turn bluish-purple; those attacked late may turn brown. After periods of high hu midity, the fungus produces spores abundantl on the surface of the infected capsules, and 1 black, smutty appearance results. Pedicels o the capsules also are attacked, and capsul often drop from the plant. Some varieties as pear to be affected less severely than other but no immune or highly resistant varieti are yet available. In years of normal rainfa_ on the High Plains, Alternaria capsule mol likely will present no difficulties with castor; bean production. Bacterial leaf spot, caused by Xanthomo j ricinieola (Elliott) Dowson, occasionally h . caused serious damage to castorbeans in Texa The last serious outbreaks were during "195, 54 when highly susceptible normal-interned,» varieties were grown. The disease was mo severe in northeastern Texas, but was prese on the High Plains, with serious economic lo occurring in some fields. The disease oftei is evident on cotyledonary leaves of emergin seedlings; water-soaked spots (lesions) appe- and gradually turn black upon drying of t cotyledons. Water-soaked spots of the sam p} ar on young leaves and frequently nd form large, blackened areas. Heavy tion results in yellowing and prema- 88f’, drop. Blasting of immature capsules king over of girdled racemes and c_e=~ occur in very severe cases. The iii is seedborne but also may over- ‘fin diseased plant material. It is iefly by hard, blowing rains. Hot, {her following infection often prevents bedspread of the disease; the infected p and new leaves are produced by The present dwarf-internode vari- moderate resistance to bacterial leaf llother castorbean diseases have been win Texas, but are not problems in the production area. Gray mold, caused tinia ricini Godfrey, is a serious prob- castorbeans are grown on the Gulf ce it destroys the racemes in all . development. The disease may occur areas during periods of high rainfall. fgno effective control. Although vari- er markedly in tolerance, no immune . resistant varieties are yet available. root rot, caused by Phymatotriehum (Shear) Duggar, attacks castor- f== the plants should not be grown on soils. There has been no indication pl resistance to the disease. “ern blight, caused by Sclerotium cc., and Cercospora leaf spot, caused Qspora ricinetla Sacc. & Berl., have rved in isolated spots in Texas. Char- caused by Macrophomina phaseoli i s Ashby, has been reported on castor- i College Station, but can occur in as. STING -internode castorbeans usually are harvest about 10 days after a killing .1. w .. $7 dLelft, USDA-type harvester, tractor-mounted; right, a harvester (factory-built) mounted on a self-propelled combine. frost, if normal drying weather prevails. Cap- sules should be dry enough for the seed to hull when rubbed between the hands. One two-row harvester-huller can harvest 300 to 500 acres per season, if favorable weather prevails. The present harvesters shake the dry cap- sules from the standing plants, hull the seed and elevate the clean seed to a holding bin. Rotating beaters hit the plants about 6 to 8 inches above the ground and induce low-fre- quency vibrations that knock the capsules from the racemes. Hullers are of two types: the USDA-designed huller has a horizontal rubber- covered disc and the other, a rubber-covered cylinder. The seed are emptied from the holding bin into a truck and hauled to the receiving point. Harvesters used during the 1958-59 harvest were manufactured largely in Plainview by a local machine shop. They were mainly two- row, tractor-mounted machines patterned after the USDA-designed castorbean harvester. Two four-row machines (one tractor-mounted and one combine-mounted) also were made in Plainview in 1958. torily with cylinder-type hullers. One com- mercial firm operated a combine-mounted ex- perimental two-row castorbean harvester in 1957-58. In 1959, this company manufactured three two-row attachments for one of its self- propelled combines, and these were sold to growers in the Plainview area. Five four-row attachments also were made by the local ma- chine shop for the same type of combine. These combine attachments for harvesting castor- beans can be taken off and replaced with the original grain header and threshing cylinder for harvesting small grain or grain sorghum. Cost of a two-row machine shop manufactured combine attachment in 1960 was approximately $3,200; cost of the four-row attachment was about $5,800. :/.___ g2 f‘ - \\ 9 Both operated satisfac-e Fig. 8. Four-row harvester (machine shop built) mount- ed on a self-propelled combine. Combines and trucks used to harvest and haul castorbeans must be cleaned thoroughly before being used for other agricultural prod- ucts. Since castorbeans are poisonous to hu- mans and livestock, contaminated grain cannot be sold. Castorbeans store well. Castorbeans in storage for 2 years have yielded oil that met Fig. 9. Close view of harvesting mechanism. A rotary beater (1) shakes the capsules from the plant. Brushes (2) seal around the base of the plants and augers (3) move the capsules to a series of vertical augers for delivery to the hullen-Courtesy L. D. Schoenleber, USDA. 10 national stockpile specifications for No. 1 castor oil. The oil from cracked and broken seed was slightly lower in free fatty acid than that from sound whole seed. Freshly hulled, seed with not more than 6 percent moisture and 5 percent cracked and broken seed should not deteriorate significantly in storage for at least 2 years. cosTs AND RETURl§l§ The cost of producing an acre of high- yielding, dwarf-internode castorbeans under irrigation on the High Plains is $45 to $60 per acre. This estimate includes cost of lan preparation, planting, irrigation, fertilizefii cultivation, insect control, mechanical har- vesting and hauling. It does not include a cost for land use. i Castorbeans are bought at a price related‘, directly to the world market for castor oil and castorbeans, with a freight deduction f0 a moving them from the production area to the processing plant. There are now no acreag controls and no price-support programs. Dis- regarding abnormally high wartime markets, prices fluctuated from 4.5 to 6.5 cents pe pound from 1947 to 1959, but are expected t‘ fluctuate less as domestic production is stabil- ized. Yields were approximately 1,000 t‘ 2,500 pounds per acre during the first 8 year) of commercial dwarf-internode castorbean pro duction. An overall average of 1,800 pound per acre was produced in 1958. Lower yield were produced in 1957 and 1959. Gross incom from an acre of castorbeans which produce 1,800 pounds per acre, marketed at 5 cent per pound, would be approximately $90, wit an adjusted return after deducting productio costs, but not land costs, of approximately $3 to $45 per acre. Before growing castorbeans, arrangemen ~ should be made for seed of an adapted variety and for marketing the crop. A custom oper ator also should be engaged tentatively to harf vest the crop, if the grower does not own . harvester. More harvesting machines shoul soon solve this problem. Companies currentl buying castorbeans in Texas have their re ceiving points located at Plainview. Castor beans are bought by weight on a clean-bea basis. Grower contracts currently specif a that the grower will receive a minimum pric or the market price at delivery, whichever higher. CROPPING SEQUENCES Present mechanical harvesters leave 5 to 1 percent of the castorbean seed in the field This loss presents a problem for crops tha follow. Since castorbean seed germinate f» -- the following spring, a pasture or p should not be planted after castor- Castorbean plants are unpalatable to 1 k, but some might be consumed with the stand could be toxic if taken in sufficient ies. Although castorbeans sometimes pgnted after castorbeans to escape the r problem, this practice is not recom- because losses from disease usually n sorghum and cotton most commonly castorbeans in the Plainview area. orghum is probably the most suitable f, proper precautions are taken. Grain should not be planted earlier than Qne so that a high percentage of the r castorbean plants can be destroyed by jtion before and at planting. Any castor- plants that emerge after planting and cultivation should be removed by hand royed by herbicidal sprays, such as ibefore the grain sorghum reaches the ge. One castorbean plant in a grain field at harvest time could result in ‘Qconsequences. A lot of grain sorghum ntains only a few fragments of the plant will be classed as sample j the Grain Division of the Agricultural 'ng' Service, USDA. Such contamina- euld result in losses where the grain is ivestock. one-may follow castorbeans, but more may be encountered in controlling castorbean seedlings early in the sea- “n with grain sorghum. Since cotton y is planted earlier than grain sorghum, ‘ little opportunity to destroy volunteer Nan seedlings prior to planting. Hand QLOr replanting may be necessary where i number of volunteer castorbean seed- erge with the cotton. Once the cotton established, volunteer castorbean seed- ually are eliminated in normal cotton ion operations. harvesting castorbeans, care should gen in preparing the land for the suc- In; Fig. 10. After castorbeans are unloaded at a receiving point, they are graded and bought by weight on a clean- bean basis. ceeding crop in order to control volunteer castorbean plants more easily. The shattered seed should remain near the soil surface; plowing with moldboard or disc plows to depths of 6 to 8 inches should be avoided. Chisels can be used for deep tillage without turning the soil, and a disc harrow will put the top few inches of soil in good condition. Seed- bed preparation for the following row crop then can be completed by listing the land. In this way, germination of shattered castorbean seed will occur in a relatively short period the next spring, and the seedlings can be destroyed more quickly than where seed were turned under several inches deep and emergence ex- tended over a prolonged period. Castorbean crop residues are valuable sources of organic matter and plant nutrients when returned to the soil. The stalks are broken easily by mechanical stalk cutters or stalk shredders, and the plant residues decom- pose readily when incorporated into the soil. The hulls have proved slightly better than dairy manure in fertilizer value, and they are scattered over the field during harvest, 11 Castorbean seed are poisonous to man 1 animals. The toxic substance is called ricin Results of feeding experiments with leav a». and stems are conflicting as to the presence o a poisonous substance, but contamination o, grain and forage with these plant parts shoul be avoided. The plant is unpalatable to live, stock, and most animals avoid eating it unlesi deprived of desirable feed. Allergens also are contained in the see? These substances, separate and distinct fro_ the toxic constituents, can cause strong allergi‘ reactions in some people.» Texas Agricultural Experiment Station, R. D. Lewis, Director, College Station, Texas s; um 01