Yield Response to Different Cover Crop Planting Dates

Dordt College

2016 Growing Season

Author: Imanuel Feodor

Introduction

Cover crops are beneficial in a farming system. Their benefits include: preventing erosion, holding nutrients (prevents leaching), and grazing (Clark, 2007). However, most of the time farmers planted these cover crops very late in the season (close to or after harvesting) due to the fear of losing yields if cover crops get planted earlier. Consequently, farmers could not get maximum benefits from the cover crops because they have minimal biomass for forages, or their roots are not adequate to hold the nutrients before the frost comes. Dordt College is experimenting on the yield response of different cover crops related to planting dates in corn.

Materials and Methods

We used annual rye as a cover crop in the corn field with only one variety: Pioneer P0 339 AMXT. The trial was conducted at the Dordt College Agricultural Stewardship Center in Sioux County, Iowa. Annual rye was under-seeded on a 10-acre plot divided into 4 replications of 12 rows.The trial consisted of 3 randomized, complete block designtreatments—early planting, late planting, and control.The first annual rye seeds were broadcast on June 27, 2016 when the corn was in stage V6 (6 visible leaf collars). The second annual rye seeds were broadcast on August 5, 2016 when the corn was in stage R2 (Kernels are very small and white in color). The plots were monitored and managed well to ensure that other factors, such as weeds and insects, would not have an impact on the results of the trial. These managements included 150 pounds of nitrogen and Triplex Flex®, which were applied pre-planting, while Round Up® and Calisto® were applied post planting. We harvested the plot on October 27, 2016 (Table 2 shows the overall data). Each replication was weighed, and moisture tests were conducted separately. The yield was then calculated using a corn yield formula.

Results and Discussion

The results show that there were no significant statistical differences (P=0.79) on yield between the different annual rye planting dates. Table 1 and Chart 1 showed the average yield for corn that was under- seeded annual rye in stage V6, stage R2, and the one without annual rye(control).

Table 1- Average yield

V6 / R2 / Control
Rep 1 / 249.2 / 251.3 / 250.7
Rep 2 / 227.7 / 231.7 / 238.5
Rep 3 / 231.3 / 238.8 / 236
Rep 4 / 244.3 / 243 / 243.4
Ave / 238.125 / 241.2 / 242.15

Although many farmers avoid planting cover crops due to the fear of losing yield, this study suggests that planting cover crops, even as early as V6, does not have a significant difference on yield, compared to the corn that was not under-seeded with cover crops.

In addition, the result of this study can help convince farmers that applying cover crops is not a loss that has to be done in order to sustain the environment. On the contrary, research (Clark, 2007) suggested that cover crops help prevent erosion, prevents nutrient leaching, and is a good source for forages.

Chart 1- Average yield

Table 1- Overall Data

Acknowledgements

Mike Schouten- Agriculture Stewardship Center Manager

Clark, A. (2007). Managing cover crops profitably (3rd ed.). College Park, MD: SARE.