Sorghum:Guidelines
GUIDELINES: SORGHUM PRODUCTION
Contents
STATISTICS
OUTLINE OF MANAGEMENT ACTIVITIES
Cultural Practices
_____ Test soil for nutrient status and pH every year. Maintain records of test results and fertilizer applications. _____ Side-dress applications of nitrogen must be applied prior to the boot stage. _____ Good soil moisture is required as seeds germinate and grow slowly. _____ Early weed control is necessary to eliminate competition for sunlight, nutrients, and water.
Pesticide Management
_____ Use approved and registered pesticides according to label. _____ Maintain application records including date, location, applicator, target pest, pesticide name, EPA registration number, formulation, rate and number of acres treated are maintained. _____ All sprayers are calibrated at the start of the season. _____ Minimize pesticide drift. _____ Develop and implement a resistance management plan. _____ Select pesticides which will preserve natural enemies of pests. _____ Use separate sprayers for herbicides and insecticides. _____ Check sprayer(s) calibration at least once during the season. _____ Recalibrate each sprayer as needed. _____ Maintain records of planting dates for treated fields. _____ Keep records of stage of crop of treated field. _____ Use water-sensitive spray cards to test coverage of leaf surfaces.
Insect Pest Management
_____ Scout "SUSPECT INSECTS" .. Aphids .. Armyworms .. Black Grass Bug .. Corn Leaf Aphid .. Cucumber Beetles .. Cutworms .. English Grain Aphid .. Grasshoppers .. Greenbug .. Mites .. Range Crane Fly .. Rose Grass Aphid .. Spider Mites .. Stink Bugs .. Thrips .. Wheat Stem Maggot .. Wireworms
_____ Identify major insect pests. _____ Keep a scouting record. _____ Identify control measures and implement according to thresholds.
Disease Pest Management
_____ Identify major diseases. _____ Keep a scouting record. _____ Identify control measures and implement according to thresholds.
Weed Pest Management
_____ Scout "SUSPECT WEEDS" .. barley, hare (Hordeum murinum ssp. leporinum) .. barnyardgrass (Echinochloa crus-galli) .. bassia, fivehook (Bassia hyssopifolia) .. bindweed, field (Convolvulus arvensis) .. bluegrass, annual (Poa annua) .. brome, ripgut (Bromus diandrus) .. burclover, California (Medicago polymorpha) .. buttercup, crowfoot (Ranunculus sceleratus) .. canarygrass, hood (Phalaris paradoxa) .. canarygrass, littleseed (Phalaris minor) .. chamomile, mayweed (Anthemis cotula) .. chickweed, common (Stellaria media) .. fiddleneck, coast (Amsinckia menziesii var. intermedia) .. filarees (Erodium spp.) .. foxtails (yellow and green)(Setaria spp.) .. goatgrass, jointed (Aegilops cylindrica) .. goosefoot, nettleleaf (Chenopodium murale) .. groundsel, common (Senecio vulgaris) .. henbit (Lamium amplexicaule) .. johnsongrass (Sorghum halepense) .. knotweed, prostrate (Polygonum aviculare) .. kochia (Kochia scoparia) .. lambsquarters, common (Chenopodium album) .. lettuce, prickly (Lactuca serriola) .. mallow, little; cheeseweed (Malva parviflora) .. milkthistles (Silybum spp.) .. lettuce, miner's (Claytonia perfoliata) .. mustards (Brassica spp.) .. nettle, stinging (Urtica dioica) .. nutsedge, yellow (Cyperus esculentus) .. oat, wild (Avena fatua) .. oxtongue, bristly (Picris echioides) .. pigweed, redroot (Amaranthus retroflexus) .. pimpernel, scarlet (Anagallis arvensis) .. pineapple-weed (Chamomilla suaveolens) .. polypogon, rabbitfoot (Polypogon monspeliensis) .. radish, wild (Raphanus raphanistrum) .. redmaids; desert rockpurslane (Calandrinia ciliata) .. rocket, London (Sisymbrium irio) .. ryegrass, Italian (Lolium multiflorum) .. shepherd's-purse (Capsella bursa-pastoris) .. smartweed, swamp (Polygonum coccineum) .. sowthistle, annual (Sonchus oleraceus) .. sowthistle, spiny (Sonchus asper) .. nettle, burning (Urtica urens) .. spurry, corn (Spergula arvensis) .. starthistle, yellow (Centaurea solstitialis) .. stickleafs (Mentzelia sp.) .. sunflower (Helianthus sp.) .. tarweeds, coast (Hemizonia corymbosa) .. tarweeds, hayfield (Hemizonia congesta) .. thistle, Russian (Salsola tragus)
_____ Prepare weed maps in mid-to-late season, indicating significant weed species and their location. _____ Use last year's scouting records to begin this year's scouting. _____ Base all herbicide rate, selection and spot or strip sprays on weed survey results. _____ Weeds may be controlled by cultivation, with no herbicide applied. _____ Use reduced rates of herbicide through banding of herbicides and cultivation. _____ Do not use herbicides of the same class on the same field in succeeding years. (Use crop rotation and corresponding herbicide selections.) _____ Prevent weeds within the field, alleys and roadways from going to seed. _____ Use an experimental plot to test different weed management techniques and record the results.
Weather and Crop Monitoring
_____ Monitor weather and crop parameters _____ Keep daily records.
Date: - Min/max temperatures: - Rainfall: - Hours of leaf wetness: - Stage of tree development (by cultivar, weekly):
CULTURAL PRACTICES
Recent technological advancements have tripled the yield of grain sorghum with an average yield of over 60 bushels per acre. The average yield of sorghum produced has increased with new technology with some growers producing more than 180 bushels per acre.
Crop Establishment
The best success will be obtained when a high plant population is established and this can be determined by the fields in which the sorghum will be growing. In fields that exist in dryland areas, the population should be about 50,000 plants per acre and in moist areas the population should be about 100,000 plants per acre. The plants should be spaced in narrow rows 20-30 inches apart and the soil should be loose and moist. It is extremely important that the weeds are controlled while the sorghum seedlings are becoming established, as they do not compete well and the weeds can easily kill the seedlings.
FERTILIZATION
Maintaining a high level of soil fertility is essential for high yields. A soil test should determine the amounts of nitrogen, potassium and phosphorus that the soil requires. However, a rule of thumb for determining nitrogen levels can be used which requires 2 pounds of nitrogen for every 100 pounds of yield goal up to 6,000 pounds per acre. Any yield beyond 6,000 pounds per acre would require three pounds of nitrogen rather than two.
Fertilizer Application
The timing of fertilizer application for sorghum is very important. After the plant has emerged, the plant has taken up most of its fertilizer requirements at 60 days. Therefore, additional nitrogen applications should be made within 30 days after emergence to assure a proper head size. It is important that the plant always has sufficient nutrients available so that the stems and leaves do not have to give their nutrients up for the head.
Fertilizer Economics
Proper fertilizer, good tillage, proper hybrid selection, proper stand, and good pest control are all essential for high grain sorghum yields.
Nitrogen Price Interactions
Research indicates that the highest yields are associated with high nitrogen levels. Fields that use higher fertilizer rates profit more than those that use lower rates, even with the added expense of extra fertilizer. Nitrogen fertilizer also increases protein, which is important as sorghum becomes more valuable in feed rations.
Phosphorus Price Interactions
Phosphorus, along with nitrogen, is needed to obtain high sorghum yields, but no studies have been performed that indicate its productivity.
Potassium Price Interactions
Potassium is also essential for high grain yields and for sturdy stalks. High rates of potassium fertilizer are needed for high, profitable yields.
Summary
One of the best ways to assure high yields and profits with grain sorghum is through adequate fertilization, which should be based upon the needs of the crop for optimal production. Sacrificing profitable yield increases by trying to minimize fertilizer costs is poor economics.
HARVEST
Timely harvest is important to assure a high yield. Sorghum should be harvested when there is 22-24% moisture in the grain and dried immediately to 12-13% moisture for proper storage.
SUMMARY
To maintain high yields, a high plant population, adequate moisture, a high level of fertilizer, good cultural controls, and a timely harvest are all necessary.
