Spring-Interseeded Winter Rye Seeding Rates Influence Weed Control and Organic Soybean Yield

Abstract

Field research in 2002 and 2003 evaluated spring-interseeded winter rye (Secale cereale L.) at 67, 134, or 200 kg ha −1 at two soybean (Glycine max (L.) Merr.) row spacings (19-and 76-cm) on weed control, yield, and gross margins. Based on regression analysis, wide-row (76-cm) soybean grain yield and gross margins were greatest when winter rye was interseeded at 114 and 106 kg ha −1 , respectively. Yields and gross margins for wide-row soybean were 8 to 55% greater than narrow-row (19-cm) soybean seeded at 494,000 or 742,000 seeds ha −1 which was probably due to flexibility for implementing cultivation. As interseeded rye rates increased from 67 to 200 kg ha −1 , yields and gross margins for narrow-rows decreased. Soybean row spacing had minimal impacts on specific weed species and total weed biomass or density. The use of wide-row soybean and spring-interseeded rye at 67 kg ha −1 was more cost-effective compared to narrow rows.

Spring-seeded winter rye living mulches enhance crop biodiversity and promote reduced tillage organic soybeans

“…Therefore, organic producers are seeking adaptive management strategies to achieve weed suppression while maintaining reduced tillage systems without relying on fall-planted covers. Interseeding winter rye simultaneously with soybeans as a living mulch has been demonstrated as an alternative weed control approach that minimizes soil disturbance in organic soybean production (Thelen et al, 2004;Uchino et al, 2009;Nelson et al, 2011), would not rely on operational timing in the fall, and could even enable stale seedbed techniques in the spring prior to planting.…”

“…While spring-seeding winter rye as a living mulch in soybean production systems was initially proposed in the 1950's, knowledge on agronomic best management practices remains limited. Explorations into variations on rye seeding rate (Ateh and Doll, 1996;Nelson et al, 2011), soybean seeding rate (Thelen et al, 2004), rye and soybean planting dates (Thelen et al, 2004;Nelson et al, 2011), and soybean row spacings (Nelson et al, 2011) have been examined in the literature. High soybean seeding rates and narrow rows have been recommended as cultural weed control strategies that can result in earlier canopies and greater direct competition with weeds (Holshouser and Whittaker, 2002;Mortensen et al, 2012;Datta et al, 2017).…”

“…High soybean seeding rates and narrow rows have been recommended as cultural weed control strategies that can result in earlier canopies and greater direct competition with weeds (Holshouser and Whittaker, 2002;Mortensen et al, 2012;Datta et al, 2017). However, planting soybeans on narrow rows increases risk as it precludes the opportunity to perform cultivation if weed control from the rye living mulch becomes inadequate (Uchino et al, 2009;Nelson et al, 2011). Planting rye prior to soybean planting has been seen as impractical as rye growth competes strongly with soybeans for resources (Robinson and Dunham, 1954;Uchino et al, 2009).…”

“…Given the potential utility of spring-seeded rye as a reduced tillage weed control measure in organic agriculture, further research is required to optimize management and address yield losses (Uchino et al, 2009;Nelson et al, 2011). The objectives of this study were to understand potential risks and benefits from (1) interseeding winter rye with soybeans and (2) delaying soybean planting date within the context of a spring-seeded rye system on weed prevalence and soybean production in the Upper Midwest to further guide adaptation of organic weed management strategies.…”

Management impacts on GHG emissions and yield for an organic soybean crop||Management impacts on GHG emissions and yield for an organic soybean crop

“…The distribution of organic matter in the soil profile can be changed as the soil is mixed and aeration increases . These negative effects are especially apparent in areas of highly-erodible soil types, where producers are concerned about topsoil loss from erosion due to greater tillage intensity (Nelson et al, 2011).…”