Establishment and Function of Cover Crops Interseeded into Corn

Abstract

Cover crops can provide ecological services and improve the resilience of annual cropping systems; however, cover crop use is low in corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotations in the upper Midwest due to challenges with establishment. Our objective was to compare three planting methods to establish cover crops (winter rye [Secale cereale L. ‘Rymin’], red clover [Trifolium pretense L. ‘Medium’], hairy vetch [Vicia villosa Roth], field pennycress [Thlaspi arvense L. ‘MN‐106’], and a mixture of oat [Avena sativa L.], pea [Pisum sativum L.], and tillage radish [Raphanus sativus L.]) (MIX) in corn at the seven‐leaf collar stage. Planting methods included directed broadcast into the inter‐row (DBC), directed broadcast with light incorporation (DBC+INC), and a high‐clearance drill (DRILL). The DRILL method achieved greater fall biomass than DBC for all species except pennycress, and DRILL and DBC+INC increased red clover and hairy vetch spring biomass compared with DBC. Cover crops did not affect corn grain or silage yield and reduced yield of the subsequent soybean crop by 0.4 Mg ha−1 (10%) only when poor termination of hairy vetch occurred at one site. Cover crops with >390 kg ha−1 of spring biomass reduced soil nitrate‐N compared with the no‐cover control. These results support that cover crops can be interseeded into corn at the seven‐leaf collar stage in the upper Midwest to reduce soil nitrate‐N while maintaining corn and subsequent soybean yields; however, effective cover crop termination is critical to avoid competition with the subsequent soybean crop.

Interseeding cover crops in corn

“…It was evident that cover crops were not competitive with corn or summer annual weeds at the densities established at our research sites. Our research used broadcast interseeders, which results in lower densities of cover crops compared with drilled interseeders (Noland et al., ). Further research is necessary to explore the competitiveness of higher densities of cover crops seeded from V2–V5 in corn, since annual ryegrass drill interseeded prior to V4 produced over 1500 kg ha −1 , nine times greater than average biomass production in our research, and reduced corn grain yield (Curran et al., ).…”

“…and crimson clover seeded as a single species and in mixtures (Abdin et al., , ; Belfry & Van Eerd, ; Caswell, Wallace, Curran, Mirsky, & Ryan, ; Curran et al., ; Grabber, Jokela, & Lauer, ; Scott, Mt. Pleasant, Burt, & Otis, ; Youngerman, DiTommaso, Curran, Mirsky, & Ryan, ; Zhou, Madramootoo, MacKenzie, Kaluli, & Smith, ), and oilseed radish ( Raphanus sativus L.) interseeded as a single species in Pennsylvania and Ontario, Canada (Belfry & Van Eerd, ; Roth, Curran, Wallace, Ryan, & Mirsky, ) and in a mixture in Minnesota (Noland et al., )…”

“…Furthermore, Noland et al. () reported no reduction in corn yield when cover crops were interseeded at the V7 corn growth stage, regardless of interseeding method (drilled, broadcast, broadcast and incorporation). There is no research that directly compares interseeding success at each of the V2–V7 corn stages.…”

“…and crimson clover seeded as a single species and in mixtures (Abdin et al, 1997(Abdin et al, , 1998Belfry & Van Eerd, 2016;Caswell, Wallace, Curran, Mirsky, & Ryan, 2019;Curran et al, 2018;Grabber, Jokela, & Lauer, 2014;Scott, Mt. Pleasant, Burt, & Otis, 1987;Youngerman, DiTommaso, Curran, Mirsky, & Ryan, 2018;Zhou, Madramootoo, MacKenzie, Kaluli, & Smith, 2000), and oilseed radish (Raphanus sativus L.) interseeded as a single species in Pennsylvania and Ontario, Canada (Belfry & Van Eerd, 2016;Roth, Curran, Wallace, Ryan, & Mirsky, 2015) and in a mixture in Minnesota (Noland et al, 2018) A major concern with interseeding is whether cover crops will act as weeds and compete with corn (Hall, Swanton, & Anderson, 1992). The competitiveness of weeds in corn depends on the time the weeds emerge in relation to corn emergence, weed species, and weed density.…”

A critical review of the impacts of cover crops on nitrogen leaching, net greenhouse gas balance and crop productivity

“…A review by Tonitto et al (2006) reported a 10% reduction in grain yield of primary crops under legume cover crops. Noland et al (2018) found that to reduce soil NO 3 while maintaining corn and subsequent soybean yields, cover crops should be inter-seeded into corn at the seven-leaf collar stage. Dozier, Behnke, Davis, Nafziger, and Villamil (2017) and Marcillo and Miguez (2017) found non-legume cover crops had no effects on the grain yield of corn, especially in the short term.…”