Early Season Production System (ESPS) Still Fit Mississippi Production?
The issue of planting date, variety selection and seeding rate of soybean has been discussed and/or argued for many years. The pioneering work of many Mid-South soybean researchers with the Early Season Production System (ESPS) and its validity has been well documented in both research plots and producer fields for many years. Simply put, this system encourages the use of early maturing varieties, typically MG IV in Mississippi, planted early to avoid late season stress from heat, drought, insects, etc.
As soybean varieties change and new traits and germplasm are brought forward it would stand to reason that the tried and proven ESPS still fits today’s practices. To test this hypothesis a study was recently conducted at the Miss. State University, Delta Research and Extension Center, in collaboration with Pioneer Hi-Bred International, to evaluate several soybean maturity groups at different plant populations and planting dates. The varieties evaluated were Pioneer 93Y92, 94Y40, 94Y70, 94Y80, 95Y01 and 95Y10. All varieties were planted on 30†rows at two seeding rates, 100,000 and 150,000 seeds/acre. Target planting dates were April 15 and May 15 with actual planting occurring on April 18, 2011 and May 16, 2011. All seed received a fungicide and insecticide seed treatment. All plots were irrigated as needed.
Data collected at harvest included total node counts, plant height and yield. The results indicate that planting date had a significant impact on each of these variables (Table 1). On average, the total number of soybean nodes were roughly 3 nodes greater for May planted soybean (20 nodes) than those planted in April (17 nodes). Similarly, plant height was influenced, where May planted soybean were, on average, 5†taller than April planted soybean at 37†and 32â€, respectively. The real story, however, is with soybean yield where April planted soybean yielded 68 bu/acre across varieties whereas May planted soybean averaged 55 bu/acre. One interesting observation was that Pioneer 93Y92 had comparable yields at both planting dates. This preliminary data suggests more research is needed to determine the best fit for modern MG III soybean cultivars in the ESPS. Also of note, plant population did not have a significant impact on soybean total nodes, plant height or yield. The lack of differences observed among plant populations could have been attributed to soybean being cultivated on 30†raised beds, established on a well-drained soil with excellent fertility.
In summary, planting soybean in the ESPS can significantly increase soybean yields. There will always be exceptions and other commercially available varieties would likely fit into this model as well. It has been and all ways will be recommended to try new and unproven varieties and/or new production practices on a limited acreage on your specific farm to determine what program or varieties work best for you.
Very nice study Tom. I was especially interested that you found no significant difference in yield among populations. I agree this is probably the case with beans planted in rows; but I believe you will find that with drilled beans in spacings even as wide as 15 inch the high populations will tend to lodge fairly early into their maturation period, thereby limiting yield and increasing tendency toward disease and insect problems since light can’t penetrate the canopy and the plants remain wet well past the time when erect plants would dry off after dew or rain. Also, control measures are not as easily done and products can’t penetrate into the canopy well enough to produce their best results. This is a complex issue; and is greatly complicated by all the various practices used by producers.