Winter canola yield and nitrogen use efficiency in a semiarid irrigated condition

Authors: PAYE, WOOIKLEE - New Mexico State University; Begna, Sultan; GHIMIRE, RAJAN - New Mexico State University; ANGADI, SANGAMESH - New Mexico State University; SINGH, PARAM - New Mexico State University; UMESH, MATHADA - University Of Agricultural Sciences; DARAPUNENI, MURALI - New Mexico State University

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/21/2021
Publication Date: 1/27/2021
Citation: Paye, W., Begna, S.H., Ghimire, R., Angadi, S., Singh, P., Umesh, M., Darapuneni, M. 2021. Winter canola yield and nitrogen use efficiency in a semiarid irrigated condition. Agronomy Journal. 113(2):2053-2067. https://doi.org/10.1002/agj2.20611.
DOI: https://doi.org/10.1002/agj2.20611

Interpretive Summary: Winter canola is a potential alternative and economical crop for the semiarid Southern Great Plains (SGP) of USA. Acreage under winter canola has increased in recent years but an independent guideline on fertility recommendation is lacking in the SGP. Our study evaluated growth, forage quality, seed yield, and nitrogen use efficiency with different timings of nitrogen (N) applications under semiarid irrigated conditions in winter canola. Two canola varieties and four N application timing treatments were examined in the study. Nitrogen timing treatments, included 100% of N applied in fall and in spring,respectively, 50% in fall and in spring (fall-spring split),respectively, and 25% in fall, spring and before flowering,respectively. Winter dry matter accumulation was greater with fall N application, while forage quality was better with fall-spring split treatment. Similar seed yields were obtained with spring (100% N), fall-spring split and 25% N (in fall, spring and before flowering) application. Nitrogen use efficiency was the highest under the 25% N treatment using 25% less N. Fall-spring split application was the most efficient N application timing when winter biomass accumulation, seed yield, and seed oil contents were considered. Fall-spring split application can be used as an effective and efficient fertility management strategy to enhance canola production and acreage in the SGP.

Technical Abstract: Winter canola (Brassica napus L.) has the potential to be an economically viable alternative crop for the semiarid Southern Great Plains of the USA. Although acreage under winter canola has increased in recent years, an independent guideline on fertility recommendation is not available for the Southern Great Plains. This study aimed to evaluate N application timing on growth, yield components, and nitrogen use efficiency in a semiarid irrigated condition for winter canola. A two-year study was designed with two canola varieties (Riley and 46W94) and four N application timing treatments. Nitrogen treatments, included F100 (100% of N applied in fall), S100 (100% of N applied in spring), FS50 (50% of N applied in fall and 50% in spring), and FSB25 (25% of N applied in fall, 25% in spring and 25% before flowering). The winter dry matter accumulation was greater with the fall N application, while the forage quality was better with FS50 treatment. The highest seed yield of 2539 kg ha/1 was obtained with S100, which was not significantly different from FS50 and FSB25. The N use efficiency was the highest under FSB25 that uses 25% less N, followed by S100, FS50, and F100 treatments, respectively. The FS50 with 50% of N application in fall and 50% in spring was the most efficient N timing treatment when winter biomass accumulation, seed yield, and seed oil and protein contents were considered. Fall-spring split application can be used as an effective and efficient fertility management strategy to enhance canola production and acreage in the SGP.