Establishing winter annual cover crops by interseeding into Maize and Soybean

Abstract

The limited time available for cover crop establishment after maize (Zea mays L.) and soybean [Glycine max (L.) Merr.] harvest is one of the main reasons for low cover crop adoption in the upper Midwest. Therefore, a 2-yr multilocation study was conducted to evaluate winter annual cover crops establishment, their effect on main crop grain yields, and soil water content when interseeded into standing maize and soybean. Treatments were three interseeding dates (broadcasting at R4, R5, and R6 growth stages for maize, and R6, R7, and R8 for soybean) and three cover crops (win-winter rye [Secale cereale L.] plus a no cover crop control). Cover crop establishment and growth varied with interseeding date across locations and seasons for both maize and soybean systems. Averaged over the years, rye produced more green cover and biomass than the oilseeds in spring. However, at the northern-most site, the greatest (40%) green cover was recorded from pennycress and indicates its potential as a cover crop. Seeding date and cover crops did not negatively affect maize or soybean grain yields or soil water content. Generally, cover crop establishment and growth were better in the soybean system than maize due to better light penetration. Further research is needed to develop better suited cultivars and/or agronomic management practices for interseeding into maize. The results of this study indicate that producers could integrate these covers to diversify and add ecosystem services to soybean production practices.Abbreviations: PAR, photosynthetic active radiation; PC, pennycress; PLS, pure live seeds; PPD, plant population density; WC, winter camelina.

Intercropping and relay cropping to increase productivity, resilience, and long-term sustainability of corn and soybean cropping systems in Iowa

“…Moreover, time of cover crop seeding in fall can influence germination and establishment under the row crop canopy. In this experiment, poor establishment of PC and WC in the fall and low survival during winter (Mohammed et. al., 2020) resulted in overall low oilseed yield for PC and WC in both C-S-C and S-S-C sequences (Table 3 and 4).…”

“…Interseeding of winter annuals into corn and soybean is possible in the NPG and Upper Midwest (Berti et al, 2017b;Johnson et al, 2017;). However, better seeding practices and agronomic management is required to improve yields of oilseed cover crops when used in corn-soybean system (Gesch and Cermak, 2011;Mohammed et al, 2020) and additional environmental (Eberle et al, 2015;Johnson et al, 2017) and rotational benefits of these cover crops require better documentation to increase their adoption by growers.…”

“…Due to incomplete factorial design of the experiments, contrast statements were used for comparing treatments and individual mean comparisons were made using the LSD at P=0.05. Data from the C-S-C sequence at Rosemount were not included in the combined analysis due to smothering of cover crops in the absence of proper corn residue management as described in the related study by Mohammed et al (2020). Data from Prosper site were analyzed for a randomized complete block using a mixed model and presented separately due to use of a different experimental design.…”

“…Cover crop survival after the winter and its subsequent growth and biomass accumulation in spring can be affected by seeding date into standing row crops (Mohammed et. al., 2020).…”

“…Across all locations, mean seed yield of PC across seeding dates was significantly greater than WC in both sequences ( Table 3). The higher yield of PC likely resulted from better fall establishment and winter survival (Mohammed et al, 2020). Mean yield of PC and WC was 344 and 201 kg ha -1 for C-S-C and 763 and 318 kg ha -1 for S-S-C rotation systems, respectively.…”