Narrow-Row Production System for Soybeans in Mississippi Delta

Abstract

The majority of irrigated soybean [Glycine max (L.) Merr.] in Mississippi are planted on raised beds spaced 38 to 40 inches apart. Recently, there has been an increased interest in planting soybean in narrower rows due to multiple potential benefits including increased light interception, improved weed control, and greater yield potential. Field studies were conducted at Stoneville, MS in 2016 and 2017 and at Hollandale, MS in 2016 to evaluate the effects of row spacing and seeding rates on irrigated soybean canopy closure, seed yield, and net returns. Row spacing treatments consisted of a single row (one plant row on a 40-inch spaced bed), twin row (two paired plant rows spaced 8 inches apart planted on 40-inch bed), and narrow row (four plant rows spaced 20 inches on an 80-inch wide bed). Each row-spacing treatment was also planted at seeding rates of 100,000, 140,000 and 180,000 seeds acre -1 . Canopy closure was greatest with the narrow-row spacing followed by the twin-and single-row spacing. Seed yield was 12% greater for the narrow-row spacing compared to single-row spacing. Net returns for row spacing followed the same trend as soybean seed yield at both locations. At Stoneville, a $62 acre -1 economic advantage was realized for the narrow-row spacing compared with single-and twin-row spacing. Results indicate that it would be economically beneficial for soybean producers in the Mississippi Delta to switch to either a twin-row or narrow-row spacing production system for furrow irrigated soybean.

Assessing irrigation water use efficiency and economy of twin‐row soybean in the Mississippi Delta

“…The higher LAI measured under TR planting geometry could have been due to improved interception of PAR that enhanced photosynthesis and biomass accumulation, resulting in significant improvement in seed yield production (17.3% in 2018 and 10.9% in 2019) over the SR geometry. It was reported that an early canopy closure in TR and higher interception of PAR led to greater CO 2 fixation, and the accumulation of photosynthates in the pods resulted in higher seed yield (Smith et al., 2019b). In this study, we expect that early canopy closure under the TR system suppressed mid‐season weed‐seed germination and establishment (data not collected), which helped boost crop growth resulting in better yield returns.…”

Water Use Efficiencies of Different Maturity Group Soybean Cultivars in the Humid Mississippi Delta

“…The planter was set to achieve an overall plant population density of approximately 336,000 plants ha −1 . Currently, the Mississippi State University recommends a seeding rate of 345,800 seeds ha −1 for an MG IV soybean planted in April to May on clay soil [20]. Achieved plant populations were estimated at harvest by counting plants in 1 m 2 area in the two center rows at three randomly selected locations in each plot.…”

Profitability of twin‐row planting and skip‐row irrigation in a humid climate

“…Smith, Kaur, Orlowski, Sing, et al. (2019) reported improved TR profitability of $39–188 ha −1 for soybean.…”

“…The TR planting employs the same bed spacing as SR with the same number of seeds planted in two rows spaced between 18 and 38 cm on the same bed (Smith, Kaur, Orlowski, Mahaffey, et al., 2019). The evidence in the agronomic literature indicates that TR planting has the potential to improve profits for cotton and soybean production (Pinnamaneni, Annapalli, Reddy, & Fisher, 2020; Pinnamaneni, Anapalli, Reddy, Fisher, & Quintana‐Ashwell, 2020; Smith, Kaur, Orlowski, Mahaffey, et al, 2019; Smith, Kaur, Orlowski, Singh, et al., 2019; I. Stephenson et al., 2011). Although TR‐planted soybean can increase yields by as much as 23% (Bruns, 2011a, 2011b; Grichar, 2007), the evidence is not conclusive that TR planting in cotton results in consistent yield increases (Boykin & Reddy, 2010; Pettigrew, 2015; Reddy & Boykin, 2010; Reddy et al., 2009; D. Stephenson & Brecke, 2010; I. Stephenson et al., 2011).…”

“…Twin‐row‐planted cotton enhances canopy‐intercepted photosynthetically active radiation (IPAR), which may drive higher yields (D. Stephenson & Brecke, 2010). This effect is also present in TR‐planted soybean with the added benefits of the suppression of late‐season weed germination and establishment due to faster canopy closure, increased plant survival rates, and improved nutrient and water use efficiencies (Bellaloui et al., 2015; Bowers et al., 2000; Bruns, 2011a, 2011b; Grichar, 2007; Smith, Kaur, Orlowski, Mahaffey, et al., 2019; Smith, Kaur, Orlowski, Singh, et al., 2019). The TR planting is robust to planter errors, which reduces the risk in the production process (Smith, Kaur, Orlowski, Mahaffey, et al., 2019).…”