Stacked crop rotations and cultural practices for canola and flax yield and quality

Canola (Brassica napus L.) and flax (Linum usitatissimum L.) are important oilseed crops, but improved management practices to enhance their yields and quality are needed. We studied the effect of stacked versus alternate‐year crop rotations and traditional versus improved cultural practices on canola and flax growth, seed yield, oil concentration, and N‐use efficiency from 2006 to 2011 in the northern Great Plains, USA. Stacked rotations were durum (Triticum turgidum L.)‐durum‐canola‐pea (Pisum sativum L.) (DDCP) and durum‐durum‐flax‐pea (DDFP). Alternate‐year rotations were durum‐canola‐durum‐pea (DCDP) and durum‐flax‐durum‐pea (DFDP). The traditional cultural practice included a combination of conventional tillage, recommended seed rate, broadcast N fertilization, and reduced stubble height. The improved cultural practice included a combination of no‐tillage, increased seed rate, banded N fertilization, and increased stubble height. Canola stand count was 36–123% greater with the improved than the traditional cultural practice in 2006, 2009, 2010, and 2011. Canola pod number and oil concentration were 3–36% greater in the improved than the traditional practice in 2007 and 2010, but trends reversed by 5–19% in 2008. Flax stand count was 28% greater with DFDP than DDFP in 2007 and 56% greater in the improved than the traditional practice in 2010. Flax pod number, seed weight, seed yield, N content, N‐use efficiency, and N‐removal index varied with crop rotations, cultural practices, and years. Canola growth and oil concentration increased with the improved cultural practice as well as flax growth, yield, and quality enhanced with alternate‐year crop rotation and the improved cultural practice in wet years. Disciplines Agriculture | Agronomy and Crop Sciences | Soil Science Comments This article is published as Sainju, Upendra M. , Andrew W. Lenssen, Brett L. Allen, Jalal D. Jabro, and William B. Stevens. "Stacked crop rotations and cultural practices for canola and flax yield and quality. " Agronomy Journal 112 (2020): 2020-2032. doi: 10.1002/agj2.20176. This article is available at Iowa State University Digital Repository: https://lib.dr.iastate.edu/agron_pubs/643 Received: 19 September 2019 Accepted: 4 February 2020 Published online: 14 April 2020 DOI: 10.1002/agj2.20176 A R T I C L E Crop Economics, Production, & Management Stacked crop rotations and cultural practices for canola and flax yield and quality Upendra M. Sainju1 Andrew W. Lenssen2 Brett L. Allen1 Jalal D. Jabro1 William B. Stevens1 Northern Plains Agricultural Research Laboratory, USDA-ARS, Sidney, MT 59270, USA Department of Agronomy, Iowa State University, Ames, IA 50011, USA Correspondence USDA-ARS, Northern Plains Agricultural Research Laboratory, Sidney, MT 59270, USA. Email: upendra.sainju@usda.gov Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by USDA. The USDA is an equal opportunity employer. Abstract Canola (Brassica napus L.) and flax (Linum usitatissimum L.) are important oilseed crops, but improved management practices to enhance their yields and quality are needed. We studied the effect of stacked versus alternate-year crop rotations and traditional versus improved cultural practices on canola and flax growth, seed yield, oil concentration, and N-use efficiency from 2006 to 2011 in the northern Great Plains, USA. Stacked rotations were durum (Triticum turgidum L.)-durum-canola-pea (Pisum sativum L.) (DDCP) and durum-durum-flax-pea (DDFP). Alternate-year rotations were durum-canola-durum-pea (DCDP) and durum-flax-durum-pea (DFDP). The traditional cultural practice included a combination of conventional tillage, recommended seed rate, broadcast N fertilization, and reduced stubble height. The improved cultural practice included a combination of no-tillage, increased seed rate, banded N fertilization, and increased stubble height. Canola stand count was 36–123% greater with the improved than the traditional cultural practice in 2006, 2009, 2010, and 2011. Canola pod number and oil concentration were 3–36% greater in the improved than the traditional practice in 2007 and 2010, but trends reversed by 5–19% in 2008. Flax stand count was 28% greater with DFDP than DDFP in 2007 and 56% greater in the improved than the traditional practice in 2010. Flax pod number, seed weight, seed yield, N content, N-use efficiency, and N-removal index varied with crop rotations, cultural practices, and years. Canola growth and oil concentration increased with the improved cultural practice as well as flax growth, yield, and quality enhanced with alternate-year crop rotation and the improved cultural practice in wet years.