By Ashirley
What is ESSP? How Does It Differ from Traditional Full-Season Soybeans?
Traditional soybeans for south Georgia involve determinate varieties that are usually planted mid-May through early June, cultured through the summer, and harvested in early fall. Determinate varieties are very photoperiod sensitive, they have a distinct vegetative growth period (that lasts until late July-early August) that is followed by a distinct reproductive (pod development) period. Maturity date of determinate soybean varieties, adapted to South Georgia, ranges from late September to late October. The growing season for adapted determinate varieties is usually 145-160 days. These varieties usually grow and yield poorly if planted before early May.
In contrast, ESSP for South Georgia involves planting early maturing indeterminate soybean varieties (MG 4.6-5.0) in late April or early May. These varieties are also moderately photoperiod sensitive, but after the first 6-7 weeks, they grow both vegetatively and reproductively at the same time. ESSP varieties adapted to South Georgia mature late August through early September. ESSP varieties usually begin flowering in early June and pod fill by mid-June; their total growing season is usually 120-135 days. With good cultural practices, ESSP may out-yield traditional determinate soybeans 10-20 percent or more. Market price of ESSP or other beans delivered to local elevators before mid-September may be $0.50-$1.00/bushel higher than price of later deliveries. Early planting, select varieties, close rows, pre-plant nitrogen, irrigation, harvest aid, and timely harvest, along with all good basic soybean cultural practices, are needed for high ESSP yields. Poor seed quality can be a critical issue if ESSP beans are not harvested soon after maturity.
10 STEPS TO HIGH YIELDING ESSP BEANS
- Use Good Crop Rotation and Productive Soils: A weakness of most ESSP varieties is lack of root-knot nematode resistance. Planting ESSP beans in fields which are below economic thresholds of root-knot nematodes is critical to achieving high yields. Field history of nematodes should be taken into consideration and fields in question should be sampled for root-knot nematodes. Those with significant root-knot populations should not be planted to ESSP beans or should be treated with fumigant nematicide. ESSP beans should be grown on fertile, productive soils. Avoid ESSP on eroded clays, deep sands, and poorly drained Atlantic Flatwoods soils.
- Fertilize for High Yields: Start with a soil test. Lime, if needed, to get soil pH to 6.0-7.0. In addition, seek to get soil calcium and magnesium levels to 1200 and 400 lbs/A, respectively. Based on soil test results, apply enough phosphorus and potassium to raise these to high soil test levels. To stimulate early season soybean growth, apply 30 lbs/A pre-plant nitrogen. If soybeans have not been grown in recent years, apply a viable soybean nitrogen-fixing bacteria inoculant, either in-furrow or as seed treatment. Apply 10-20 lbs/A sulfur for soils with less than 1 ½ percent organic matter. For sandy soils, plan to apply ¼ – 1/3 lb/A boron as a foliar spray at beginning pod fill (R3). At beginning pod fill, around mid-June, begin collecting soybean leaf samples (uppermost fully developed leaves) weekly for tissue analyses. Monitor especially the potassium level. If this drops to a low level (below 2 percent) by late July or early R5 (full bean stage), a supplemental application of potassium may be beneficial. A supplemental application of nitrogen at this stage may also be beneficial if striving for high yields (80-100 bu/A).
- Plant in Close Rows: The objective should be to get full canopied soybeans (those with a leaf area index of 5+). When following above practices, this can usually be accomplished with row spacings of 30 inches or less, or by planting in twin rows if planting on a 36 inch bed.
- Till to Get Deep Rooting: If not using long term no-till, use in-row subsoiling or some form of deep tillage to help insure getting deep rooted soybeans. Care must be taken not to re-compact soil during seed bed preparation, planting and culture. For many farm operations using twin row planters with in-row subsoiling (on a 36” bed) may be the best way of getting the benefits of close rows and avoiding soil re-compaction. If planting in close rows (less than 24”), field traffic lanes should be established to minimize compaction and soybean plant destruction during field traffic operations.
- Plant 140-150 Thousand Seed/A: Adjust planters to plant 8-10 seed per foot for 30 inch rows. If planting in closer rows, adjust seeding rate per row downward according to row width. If planting a tall growing variety, use the lower seeding rate. Be careful not to overseed, as this can result in lodging and reduced yield potential. Seed should be placed 1-1 ¼ inches deep in moist soil. Irrigation may be needed to help insure getting a good uniform stand, and/or to activate preemergence herbicide.
- Plant Before May 15: In order for ESSP beans to have high yield potential, they need to be planted before mid-May (April 15-May 15). Planting date studies have given variable results, depending on the year and location, but best farm successes usually occur with April 20- May 1 plantings. Make sure soil temperature (2” depth) has warmed to at least 68° F before planting. Planting too early may result in reduced vegetative growth and poor seed quality. ESSP beans appear to have no yield advantage over traditional determinate soybeans when planted after mid-May. Seed should be treated with a fungicide when planting in mid-April or cool soils. An in-furrow fungicide may also be beneficial when planting in adverse conditions.
- Select ESSP Varieties Known to Have High Yield and Good Seed Quality: Getting the right ESSP variety is crucial to success. There is much to be learned about which ESSP varieties are best for South Georgia, but at present, it appears that indeterminate MG IV 4.6-MG 5.0 soybean varieties perform best for the management practices prescribed for this system. Not all MG IV varieties will have good seed quality when planted before early May. Check with seed companies to see which soybean varieties they recommend.
- Control Weeds Early: Weed management strategies for ESSP should generally be no different than those for traditional full-season soybeans. The one exception is that all weed management treatments, wherein possible, should be made before mid-June, the time when ESSP beans begin pod fill. There are high yielding Roundup Ready and Liberty Link ESSP soybean varieties. Select varieties with the herbicide tolerance trait that best fits your needs, and build a weed control program around them. The Georgia Extension Pest Management Guide is an excellent guide for developing weed management and other pest management strategies.
- Monitor and Control Insects and Diseases: Early planted soybeans will be a magnet for early season insects such as 3-cornered alfalfa hopper, kudzu bugs and stink bugs. Begin scouting ESSP soybeans early and plan for control measures when economically damaging levels occur. Be especially watchful for pod feeding insects in mid-June since this is the time when pods will start forming. Keep in touch with UGA Extension Service for updates on the presence of soybean rust disease. At R3 (around mid-June), apply the protective Dimilin/boron/fungicide spray. Repeat this spray in mid-July, as many new unprotected leaves will have developed during this four week period. Continue scouting and apply any necessary control treatments until late August, the time of physiological maturity for ESSP.
- Irrigate as Needed for Good Growth and High Yield: ESSP soybeans are not recommended for dry land production in South Georgia due to risk of poor seed quality and/or low yields. The critical period (R3-R6.5) when ESSP beans must have adequate soil moisture for top performance is mid-June through early August. Plan to supplement rainfall with irrigation during this period so that soil moisture deficit is “zeroed out” every 3 to 5 days. In dry seasons, an irrigation application before or after this period may be needed. Use a soil moisture monitoring device to determine amount of water to apply for each application.
- Use a Harvest Aid After Physiological Maturity: This treatment helps get rapid dry down and the timely harvest critical to ESSP success. For early planted MG IV varieties, the timing for this treatment will usually be the last 10 days of August. Look for all soybean leaves and pods to have turned from dark green to very light green to yellow. Check uppermost pods (the youngest) to see if they have reached this stage. Be careful not to apply harvest aid too early as such cannot only reduce yield but also significantly reduce seed quality. Remember, the soybean grain market is for yellow soybean seed. You can be docked for delivering premature green seed. See the UGA Pest Management Guide for harvest aid chemicals and application instructions.
- Plan for Timely Harvest: ESSP beans will be mature by early September, a time when day and night temperatures are usually warm enough that seed test weight and quality decline rapidly with extended field exposure. This will be especially true if frequent rains and/or high humidity continue after maturity. For this reason, plan harvest, wherein possible, by 10 days after dry down.
Source:uga.edu