On-farm trials show whether postponing termination until soybean planting gives rye longer growing periods
When it comes to understanding rye cover crop termination timing before soybeans, it can be difficult to know whether to plant green or brown.
Postponing termination until soybean planting allows rye to have more time to grow in the spring, but it is uncertain if planting soybeans “green” into rye can influence yields, a Monday Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) field crop report
To better understand if “green” soybeans can affect rye yields when planted, the Brant County Soil and Crop Improvement Association conducted a series of on-farm trials. The trials compared soybeans grown after early-terminated rye to soybeans “planted green” into rye, the report said.
Four on-farm trials took place between 2017 and 2018, with sites having between two and four field-length duplicates of early and late rye termination. Results from the trials are shown in the field crop report chart below:
Rye biomass increased, on average, by “4.3-times when terminated at time of soybean planting compared to 2 weeks prior,” across all four sites, the report said, as shown in the following chart.
Brantford 2018, the site with the largest amount of rye biomass, allowed for an additional two weeks of growth which resulted in over eight times extra plant material. Additional biomass helps to increase soil organic matter and contributes to a long-lasting mulch.
Late termination at the Brantford 2018 site further produced an extra 48 lbs./acre of nitrogen scavenged by the cover crop, from 12 to 60 lbs./acre. When taken up by rye, nitrogen is gradually released throughout the season, reducing the chance of it being lost to the environment.
Postponing the termination of rye is risky, however, as some soybean stands were reduced in some sites because of the delay.
Planting into moisture is crucial to make sure seed trenches are closed. If conditions are excessively dry prior to planting, producers should terminate rye in advance to evade having to plant in even drier conditions.
Soybeans in later-terminated rye had delayed development. Plants were consistently one growth stage behind in the “plant green” plots across all four sites in 2018, and at the Brantford site, soybeans planted green into rye had “an equal or greater number of pods per plant and seeds per pod compared to those in the early-terminated rye,” the report said.
Farms.com has reached out to the Brant County Soil and Crop Improvement Association for comment.
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