Potential of Rainfed Canola as a Double Crop in a Corn-Soybean Rotation in Mississippi

Investigators: Gurbir Singh, Gurpreet Kaur, Jagmandeep Dhillon

Date: 2021

Project Summary

Introduction

Currently, the most predominant winter crop grown in Mississippi for profit is wheat. Most of the research or demonstrations currently being cited have reported no economic return of growing wheat in Mississippi. Canola offers a potential alternative that could be grown during the same time frame as wheat and could work into a double-crop/cover-crop scenario and provide a harvestable and potentially profitable crop. The objectives of this research were to evaluate yield potential, oil seed quality, and nutrient uptake of canola grown as a double crop after corn in a corn-soybean rotation; to determine nitrogen (N) requirement and nitrogen use of canola grown in Mississippi; and to determine the economic implications of the cultural practices of canola.

Materials and Methods

The study was conducted at three locations (Locations 1, 2, 3) at the National Center for Alluvial Aquifer Research, Stoneville, MS, and one location at R. R. Foil Plant Science Research Center, Starkville, MS (Location 4). The soil series selected for these research locations were Bosket very fine sandy loam (Location 1), Commerce very fine sandy loam (Location 2), Commerce silty clay loam (Location 3), and Catalpa silty clay loam (Location 4). The experiment was designed as a randomized complete block with four replications. Nitrogen rate treatments were 30, 60, 90, 120, and 150 lb/ac N applied as urea. Nitrogen was split applied, with 30 lb/ac N at planting and the remainder at stem elongation stage during the first week of February 2021. A non-treated control with no N applications was also included in the study. Additionally, to compare the effects of double-crop canola on corn-soybean rotation, we added a winter fallow treatment where no cover crop or canola was added to a corn-soybean rotation. To determine the economic implications of the cultural practices for cover crop management with both harvestable and non-harvestable covers, we added a cover crop treatment that was planted with hairy vetch. A seed drill was used to plant canola and hairy vetch in 13 ft × 30 ft plots. Roundup Ready canola variety Star 930W was grown at all four locations at a seeding rate of 8 lb/ac. The seeding rate for hairy vetch was 20 lb/ac. Locations 1, 2, 3, and 4 were planted on 10/2/2020. 10/23/2020, 10/23/2020, and 11/6/2020, respectively. A postemergence application of Roundup at 22 oz/ac for winter weed management was applied on 12/16/2020. Data collection included plant heights and plant populations measurements at the beginning ripening growth stage. Canola aboveground biomass samples were collected before harvesting to estimated nutrient uptake in stalk and seed. Canola was harvested in Stoneville on 5/21/2021 and in Starkville on 5/27/2021 from an 80 inch swath width with a Kinkaid 8XP plot combine (Haven, KS) equipped with a harvest master grain gage (Juniper Systems, Logan, UT). Seed samples were collected during harvesting for seed quality analysis including oil, moisture, test weight and seed index. On 6/1/2021 at a seeding rate of 140,000 seeds/ac, soybean variety Asgrow 48X9 was planted in Stoneville while soybean variety Asgrow 48X0 was planted in Starkville. Soybean planted after canola in Stoneville was maintained as irrigated whereas at Starkville it was non-irrigated. Soybean was harvested on 10/8/2021 in Stoneville and on 10/11/2021 in Starkville. Soybean yield, test weight, harvest moisture, and soybean grain quality were collected at harvest in 2021. Data were analyzed using the GLIMMIX procedure in SAS 9.4 (SAS Institute, Cary, NC).

Results and Discussion

Averaged over four locations, canola seed yield was 16 to 57% greater for 120 and 150 lb/ ac N treatments compared to all other N rate treatments (Figure 1). Seed yields were similar for 120 and 150 lb/ac N treatments when average over four locations; therefore, no additional benefit was observed from 150 lb/ac N application. Maximum yield potential for the canola variety Star 930W was achieved by an N rate of 120 lb/ac N (Figure 1). There were no significant differences in oil content and plant population among N rate treatments (Table 2). Test weight ranged from 48.5 to 49.9 lb/bu and was highest for 120 lb/ac N treatment. The seed index was calculated based on the weight of 400 seeds. Non-treated control and 30 lb/ ac N had the highest seed indices of 1.75 and 1.73 grams per 400 seeds, respectively, among all treatments. Seed moisture ranged between 13.0 to 16.5 % and decreased with increasing N rate. Aboveground biomass dry weight was 1587 and 1608 lb/ac for 120 and 150 lb/ac N treatments, respectively, which was 31-50% greater compared to 0, 30, and 60 lb/ac N treatments (Table 3). Nitrogen uptake in the aboveground biomass was similar among 90, 120, and 150 lb/ac N treatments and ranged from 22.4 to 26.2 lb/ac. Sulfur uptake in the aboveground biomass was similar among 120 and 150 lb/ ac N treatments (Table 3). Sulfur uptake in the aboveground biomass was 8.8 lb/ac for the 150 lb/ac N treatment which was at least 2 lb/ac higher than the 0, 30, 60, and 90 lb/ac N treatments. Canola yield from four sites in Mississippi was at least 4.5 bu/ac lower compared to the national average yield of 37.8 and 35.5 bu/ac for 2018 and 2019, respectively (USDA-NASS, 2020).

Conclusion

Maximum yield potential for the canola variety Star 930W was achieved by an N rate of 120 lb/ac N. At an average selling price of $22/ bu, the estimated gross return of canola was $682/ac. Soybean was planted after harvesting canola in May 2021 and average yield of soybean from all four locations was 53 bu/ac. The soybean gross return was $716/ac when average selling price was estimated to be $13.50/ bu.

References

USDA-NASS. (2020). Crop Production 2019 Summary. https://www.nass.usda.gov/ Publications/Todays_Reports/reports/cropan20. pdf

Project Photos

• Crop Type:
• Corn
• Soybean

• Topic:
• Cover Crops
• Technologies