Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/18/2011
Publication Date: 6/29/2011
Citation: Bruns, H.A. 2011. Planting date, rate and twin-row vs single-row soybean in the mid south. Agronomy Journal. 103:1308-1313. Interpretive Summary: Twin-row soybean production is becoming popular with producers in the Mid South with increased seed yields being reported, especially when used in conjunction with the Early Soybean Production System. The effects of planting in twin-rows versus single-rows of an MG IV variety planted in April, May, and June at populations of 20, 30, 40, and 50 seed per square meter were evaluated on a sandy loam soil and a heavy clay both common to the Mississippi Delta. Twin- rows yielded more than single-rows on both soils. This was probably due to there being more established plants per row in the twin-rows than the single- rows. The number of pods per plant did not differ between twin-rows and single-rows. Though the experiment was irrigated, drought and high temperatures likely reduced yields in 2010 compared to 2009. Delayed planting on both soils resulted in decreased yields and increasing seeding rates above 30 seed per meter resulted in no increases in yield. Though twin-rows resulted in higher seed yields the increase was worth only about $75.00 (US) per hectare making it necessary to consider a twin-row planter’s usefulness in other crops such as corn and cotton before investing in it for soybean production.
Technical Abstract: Comparisons of twin-row vs. single-row production of an irrigated MG IV soybean (Glycine max (L.) Merr.) on a sandy loam soil and a clay indigenous to the Mississippi Delta were conducted in 2009 to 2010 at Stoneville, MS. Seeding rates of 20, 30, 40, and 50 seed m-2 were planted in four row plots spaced 102 cm apart and 9 m long using both a single-row plot planter and a twin-row planter. Three planting dates, mid-April and mid-May, representing the ESPS and a mid-June planting common to double-crop soybean were made. Data included plants at growth stage R4, nodes and pods plant-1, yield, seed bulk density, and seed weight. Twin-rows yielded more than single-rows on both soils (3.8 Mgha-1 vs. 3.6 Mgha-1 on the sandy loam; 4.2 Mgha-1 vs. 4.0 Mgha-1 on the clay). Yields in 2010 were less due to drought and heat stress. Delayed planting decreased yields on both soils while increasing seeding rates had no affect. Twin-rows on both soils had higher numbers of plants m-2 than single-rows at all seeding rates. Differences in nodes plant-1 were noted but did not affect to yield. Pods plant-1 did not differ between row configurations on either soil. Seeding rates above 30 seeds m-2 are not economically beneficial. Seed bulk densities and weights differed slightly. Delayed planting will result in decreased yields. The small yield increases combined with equipment costs makes it important to consider a twin-row planter’s usefulness in other crops before investing in it for soybean production.