Nowadays, producers are well aware of what they need to do to maximize soybean yield potential. However, reminders that can be checked from start to finish of the growing season may prove useful to pinpoint those areas that require special attention every year.
VARIETY SELECTION. Select varieties based on a combination of the below factors.
• Proven Yield Potential. Use variety trial information. Click here for MSSOY variety selection tool and here for links to the Midsouth states’ variety trial information. Click here for links to private company variety trait data, and here for the MSU-ES variety short list.
• Maturity Group. Select based on desired length of growing season and drought and pest avoidance potential. Click here for details. Click here for details about SOYMAP and directions for its use to select appropriate MG for a given location and planting date.
• Resistance to nematodes and diseases. For varietal reaction to pests, click here for Mississippi ratings and here for Arkansas ratings. Univ. of Arkansas ratings for soybean varietal performance in a root knot nematode-infested field can be found here.
• Herbicide resistance traits. Use all available varietal herbicide resistance traits to ensure that the largest number of MOA’s can be used for weed management in soybeans. For ratings of varietal susceptibility to metribuzin which may be applied preemergence in some weed control systems, click here. Click here for issues associated with use of auxin herbicides on resistant soybean varieties.
• Iron Deficiency Chlorosis (IDC). Click here for information about this malady in soybean, on what field sites to expect it, and for variety ratings in Mississippi trials. See the MSPB Scouting Guide, pages 100-101, for pictures of IDC symptoms. Use resistant/tolerant varieties on sites that have soil properties that will result in IDC-promoting conditions. The link to above private company variety trait data will likely be the best source for this information. However, not all varieties within a company list will have IDC ratings.
TILLAGE. Strive for a minimum/no tillage system. Use fall/spring tillage only where needed.
• For HR weed control. Tillage may be the only available remedy to control some HR weeds.
• To correct soil physical problems. Know the soil type/series of a particular field in order to predict physical and/or chemical barriers that may limit expansive root growth.
• Deep tillage may benefit production on some soils, and can offset the amount of irrigation water that will be applied when soybeans grown on those soils are irrigated.
SOIL FERTILITY. Maintain soil fertility levels, especially in high-yield environments, by taking soil samples and following recommendations from test results to re-supply soil nutrients according to previous yields and future yield goals.
• Sample in the fall after harvest. Click here for sampling protocol.
• Especially needed in high yield environments. Consistent high yields will remove significant amounts of fertilizer elements that must be replaced to maintain the soil fertility level needed for continued high yields. Click here for details.
• Tissue testing. Use tissue testing to verify/identify deficiency/sufficiency of major plant nutrients during the growing season so that corrective action can be applied prior to growing a following crop. Results from tissue testing cannot be used to correct nutrient deficiencies during the current growing season, but rather can be used in planning for future nutrient applications, or to validate the current fertility program for a specific crop. Thus, tissue testing for nutrient sufficiency or deficiency should be used in conjunction with results from soil tests.
FALL AND SPRING WEED BURNDOWN. Apply proper mix of spring burndown herbicides.
• Initial phase of HR weed management. Add residual herbicides for HR weed management in fields with known HR weeds. Click here for details.
• Fall-applied herbicides. Click here for details.
• Herbicide MOA. Use burndown and residual herbicides with differing MOA’s prior to crop planting. Click here for MOA details.
PLANTING DATE. Select based on the following factors.
• Last spring frost date. Match early planting time with estimated last spring frost date for a location. Click here for details.
• Drought avoidance. Plant early-maturing varieties (late-MG III–mid-MG IV) early (before ~Apr. 20) to avoid highest summer temperatures and driest summer period.
• Pest avoidance. Plant early to avoid late-season insect and rust infestations. Conversely, late plantings must be scouted more intensely for foliage and pod feeding insects that almost always appear in mid-to late-summer in the Midsouth. When soybean rust appears in the region, it is almost always after early-maturing varieties that were planted early have reached the stage beyond which rust will not adversely affect yield.
SEED TREATMENTS. Select and apply seed treatments based on the following factors.
• Soil pest problems. Select materials that control diseases, insects, and nematodes that pose a potential threat to production in individual fields; i.e., know a field’s history of pest infestations in order to use only those seed treatment pesticides that are warranted. Click here for seed treatment materials to use for common seed- and soil-borne pests. Be aware that using the proper fungicide seed treatment is the most important issue to consider.
• First line of defense. Seed treatments will ensure that the effect of early-season pests are minimized and that an intended stand and maximum early-season growth are realized so that the advantage from planting early is realized.
EARLY-SEASON WEEDS. Manage for early season weed escapes, especially of HR weeds.
• Control soon after planting. This is needed to ensure minimum weed competition and maximum yield potential. Check each post-emergence herbicide’s label for maximum allowed weed size to assure optimum control. Rotate herbicide MOA’s when possible.
CONTROL INSECTS AND DISEASES. All Midsouth soybean plantings are subject to infestation/infection by one or more insect and/or disease pests.
• Time of insect infestation. Many of the Midsouth’s invasive insects are only problematic after the onset of reproductive development in later plantings. Thus, intense scouting for insect management should occur after R1 or beginning bloom in these plantings.
• Treatment thresholds. Use thresholds for insect treatment decisions. Click here and here for up-to-date information about the treatment thresholds for various insects and for insecticide products that are available to treat for insects when thresholds are reached.
• Disease calendar. Click here for a calendar that will provide assistance in preparing for disease management decisions during the growing season.
• Foliar fungicides. Click here for a guide that provides information about foliar fungicides that can be used to manage/control common diseases that infest soybeans in the Midsouth.
• Disease management. Click here for general guidelines and resources that should be consulted for managing soybean diseases.
NEMATODES. Take soil samples to determine presence and species in order to determine control measures.
• Sampling time and protocol. Click here for protocol that includes the best time to collect samples and proper sample collecting and handling procedures. Click here for tips to consider if sampling is delayed until spring.
• Variety Trials. Select varieties with known resistance to species and race/type that are present.
• Crop Rotation. Plan a rotational cropping system to avoid yield reductions. The three nematodes of concern that affect soybeans in the Midsouth are the soybean cyst, root-knot, and reniform. Each of these has different alternate host crops that will affect the choice of a rotational crop.
PESTICIDE APPLICATION. Consider nozzle type, tank-mix options, weather conditions, and time of day when applying all pesticides. Pesticide labels will specify the criteria for most of these factors.
• Herbicide drift and spray nozzles. Click here to access two White Papers that have information about selecting the spray nozzle that will produce the appropriate droplet size to both control targeted pests and reduce drift.
• Calibration of pesticide application equipment. Click here to find guidelines presented in an MSU-ES publication to ensure proper sprayer calibration based on spray equipment factors.
• Spraying time. Click here to access what is known about the optimum time of day to spray foliar-applied herbicides on soybeans to realize their maximum efficacy against targeted weeds.
IRRIGATION. Use all available tools to ensure the most efficient application and use of irrigation water.
• Irrigation setup. Dr. Jason Krutz, former Irrigation Specialist at MSU-DREC, and Dan Roach co-authored an article entitled “Pipe Planner: the Foundation Water Management Practice for Furrow Irrigated Soybeans“. This article provides a summary of results from the MSPB-funded RISER project that defines the water savings that can be gained by using Pipe Planner, the computerized hole selection program that was developed to supplant NRCS’s PHAUCET irrigation management tool. Also, use other methods to install setups that will result in water conservation.
• Soil Moisture Sensors. Use soil moisture sensors to accurately schedule irrigations according to plant stage and available water in the soil.
HARVEST AIDS. These materials may be needed to make soybean harvest more efficient and/or to desiccate weeds that emerged and grew after in-season weed control activities were completed.
• Materials and time of application. Click here for guidelines about desiccation products and when they should be applied to soybeans to maintain yield potential and ensure pre-harvest interval.
The topics listed above are those that should be considered as the 2018 production season approaches and progresses. The content in the linked resources shown for each topic will provide up-to-date information that can be used to maximize soybean yield and economic return.
Composed by Larry G. Heatherly, Mar. 2018, email@example.com