Cereal rye cover crop seeding method, seeding rate, and termination timing effects corn development and seedling disease

Abstract

Cover crops decrease nutrient leaching from high-input cropping systems and improve soil quality. In Iowa, cereal rye (CR, Secale cereale L.) is the most adopted species due to its winter hardiness, high biomass productivity, and low cost. Field management of CR is still not completely understood, and as its adoption brings more complexity to farmers, especially with the uncertain effects on corn (Zea mays L.) yields, adoption is slow. Additionally, cover crops immobilize N and increase the inoculum of pathogens such as Pythium spp. A 2-year field experiment was conducted at three locations in Iowa investigating the effect of two seeding methods, three seeding rates, and two termination timings (one location only) of CR on CR biomass and corn growth, root disease, and yield. Cereal rye biomass and consequently corn growth and development were not affected by seeding rate but by seeding method and termination timing. Broadcast CR produced an average of 3.5 times more biomass but 7.2% less corn yield than the drilled CR. Cereal rye when terminated late (3 days before planting [DBP]) produced 2.1 times greater biomass but 4.1% less corn yield compared to early termination (14 DBP). In general, greater root rot incidence and more Pythium clade B were detected in corn seedlings sampled from broadcast CR than drilled CR. Radicle rot incidence of corn was also greater in the late-terminated plots in 1 year. Farmers should be careful using broadcast seeding and later termination of CR cover crop when planted before corn.

Does grazing winter cereal rye in Iowa, USA, make it profitable?

“…The agronomic data used for the present study include kg of cereal rye biomass in November and on the date of termination; as well as corn planting date, harvesting date, and yield. The full agronomic experiment is described in detail in Marcos et al (2023).…”

“…Private net returns to cereal rye in no-till corn enterprise Agronomic data from six location-years Marcos et al (2023) and price data were used to evaluate the net returns to cereal rye preceding no-till corn in a partial budget framework. Treatment factors for the agronomic experiment included planting date-method, seeding rate, and target termination date.…”

“…The agronomic data used for the present study include kg of cereal rye biomass in November and on the date of termination; as well as corn planting date, harvesting date, and yield. The full agronomic experiment is described in detail in Marcos et al (2023). Table 2 lists the relevant prices and costs from 2018 to 2020 used in our analysis.…”

“…We conducted the evaluation in two stages. First, the net returns to cereal rye in the crop system were calculated using experimental agronomic data from Marcos et al (2023) and local average prices in a partial budget framework. Partial budgets captured the differences between total profits from no-till corn production in fields planted to cereal rye in the fall, and total profits from no-till corn production in fields left fallow over the winter.…”