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ARS Home » Plains Area » Sidney, Montana » Northern Plains Agricultural Research Laboratory » Agricultural Systems Research » Research » Publications at this Location » Publication #333990
Title: Soil residual nitrogen under various crop rotations and cultural practices

Author
item Sainju, Upendra
item LENSSEN, ANDREW - Iowa State University
item Allen, Brett
item Stevens, William - Bart
item Jabro, Jalal - Jay

Submitted to: Journal of Plant Nutrition and Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/6/2017
Publication Date: 1/27/2017
Citation: Sainju, U.M., Lenssen, A.W., Allen, B.L., Stevens, W.B., Jabro, J.D. 2017. Soil residual nitrogen under various crop rotations and cultural practices. Journal of Plant Nutrition and Soil Science. 180(2):187–198. doi:10.1002/jpln.201600496.

Interpretive Summary: Soil residual nitrogen ([nitrate + ammonium]-nitrogen) after crop harvest results from inefficient nitrogen uptake by crops due to application of nitrogen fertilizers, manures, and other amendments. Such nitrogen can be lost to the environment through leaching, denitrification, volatilization, surface runoff, soil erosion, and nitrous oxide emissions, a potent greenhouse gas. Improved management practices are needed to reduce nitrogen fertilization rates and soil residual nitrogen by enhancing nitrogen-use efficiency while maintaining crop yields and quality. Producers are increasingly interested in reducing the amounts of nitrogen fertilizers applied to crops because of higher costs of nitrogen fertilization and the associated environmental degradation. We evaluated the effects of stacked vs. alternate-year crop rotations and cultural practices on soil residual nitrogen at the 0-125 cm depth, annualized crop nitrogen uptake, and nitrogen balance from 2005 to 2011 in the northern Great Plains, USA. Stacked rotations were durum-durum-canola-pea (DDCP) and durum-durum-flax-pea (DDFP). Alternate-year rotations were durum-canola-durum-pea (DCDP) and durum-flax-durum-pea (DFDP). A continuous durum (CD) was also included for comparison. Cultural practices were traditional (conventional tillage, recommended seeding rate, broadcast nitrogen fertilization, and reduced stubble height) and ecological (no-tillage, increased seeding rate, banded nitrogen fertilization, and increased stubble height) systems. Compared with other crop rotations, annualized crop biomass nitrogen was greater with DCDP and DDCP in 2007 and 2009, but was greater with DDFP than DCDP in 2011. Annualized grain nitrogen was greater with DCDP than CD, DFDP, and DDFP and greater in the ecological than the traditional practice in 2010 and 2011. Soil ammonium-nitrogen was greater with CD than other crop rotations in the traditional practice at 0-5 cm, but was greater with DDCP than CD and DDFP in the ecological practice at 50-88 cm. Soil nitrate-nitrogen was greater with CD than other crop rotations at 5-10 cm, but was greater with CD and DFDP than DCDP and DDCP at 10-20, 88-125, and 0-125 cm. Nitrate-nitrogen content at 88-125 and 0-125 cm was also greater with the traditional than the ecological practice. Nitrogen balance based on nitrogen inputs and outputs was greater with crop rotations than CD. Increased nitrogen fertilization rate increased soil residual nitrogen with CD, but legume nitrogen fixation increased nitrogen balance with crop rotations. Legume-based crop rotations reduced N input and soil residual N available for environmental loss, especially in the ecological practice, by increasing crop nitrogen uptake and nitrogen immobilization compared with nonlegume monocrop.

Technical Abstract: Crop rotation and cultural practice may influence soil residual N available for environmental loss due to crop N uptake and N immobilization. We evaluated the effects of stacked vs. alternate-year crop rotations and cultural practices on soil residual N (NH4-N and NO3-N contents) at the 0-125 cm depth, annualized crop N uptake, and N balance from 2005 to 2011 in the northern Great Plains, USA. Stacked rotations were durum (Triticum turgidum L.)-durum-canola (Brassica napus L.)-pea (Pisum sativum L.) (DDCP) and durum-durum-flax (Linum usitatissimum L.)-pea (DDFP). Alternate-year rotations were durum-canola-durum-pea (DCDP) and durum-flax-durum-pea (DFDP). A continuous durum (CD) was also included for comparison. Cultural practices were traditional (conventional tillage, recommended seeding rate, broadcast N fertilization, and reduced stubble height) and ecological (no-tillage, increased seeding rate, banded N fertilization, and increased stubble height) systems. Compared with other crop rotations, annualized crop biomass N was greater with DCDP and DDCP in 2007 and 2009, but was greater with DDFP than DCDP in 2011. Annualized grain N was greater with DCDP than CD, DFDP, and DDFP and greater in the ecological than the traditional practice in 2010 and 2011. Soil NH4-N content was greater with CD than other crop rotations in the traditional practice at 0-5 cm, but was greater with DDCP than CD and DDFP in the ecological practice at 50-88 cm. Soil NO3-N content was greater with CD than other crop rotations at 5-10 cm, but was greater with CD and DFDP than DCDP and DDCP at 10-20, 88-125, and 0-125 cm. Nitrate-N content at 88-125 and 0-125 cm was also greater with the traditional than the ecological practice. Nitrogen balance based on N inputs and outputs was greater with crop rotations than CD. Increased N fertilization rate increased soil residual N with CD, but legume N fixation increased N balance with crop rotations. Legume-based crop rotations reduced N input and soil residual N available for environmental loss, especially in the ecological practice, by increasing crop N uptake and N immobilization compared with nonlegume monocrop.