Blackshaw, R.

Gan, Y.

Grant, C.

Harker, N.

Johnson, E.

Lafond, G.

Lupwayi, N.

Malhi, S.

May, W.

McLaren, D.

O’Donovan, J.

St. Luce, M.

Turkington, K.

Zebarth, B.

Ziadi, N.

English

University of Saskatchewan Research Archive

Nitrogen cycling and budget in crop rotations as influenced by preceding crops and N fertilizationM. St. Luce, C. Grant, N Ziadi, B. Zebarth, J. O’Donovan, R. Blackshaw, N. Harker, E. Johnson, Y. Gan, G. Lafond, W. May, S. Malhi, K. Turkington, N. Lupwayi, D. McLarenAgriculture and Agri-Food CanadaSoils & Crops, March 6-7, 2018Global Fertilizer ConsumptionSource: International Fertilizer Industry AssociationNitrogen:▪ most limiting nutrient▪ No.1 source for N2O emissions▪ High cost associatedFate of Added N FertilizerDenitrification & VolatilizationPlant uptakeRun offLake/RiverLeachingClay fixationGround waterImmobilizationN recovery < 50% in application yearPortion derived from SOMIn Canada, 40% of N is either lost or accumulated within the systemSmil 1999; Janzen et al. 2003Alternative and sustainable approaches:▪ Crop rotation with pulses & retaining of crop residues▪ Matching N application with crop demand in space and timeSustainable Production SystemsPulses Walley et al. 2007Hossain et al. 2017kg N ha-1Faba bean 189 68Field pea 83 55Lentil 72 49Dry bean 34 9Chick pea 33 52How does crop rotation & N fertilization interact to influence N cycling under varying soil & climatic conditions?Source: University of MinnesotaTo examine the interactive effects of preceding crops and N fertilization rates on soil N cycling in canola and wheat cropping systems in western CanadaStudy ObjectiveMaterials and MethodsLacombeScottLethbridgeIndian HeadBrandonBeaverlodgeSwift CurrentMelfortMaterials and MethodsMain plots (established in 2010): ▪ Canola (45H73) grown for seed▪ Faba bean (Snowbird) grown for seed▪ Faba bean (Snowbird) grown as green manure▪ Field pea (CDC Golden) grown for seed▪ Lentil (CDC Imperial) grown for seed▪ Wheat (CDC Imagine) grown for seed▪ Field pea (CDC Golden) grown as green manure at one siteSub-plots (N rates in 2011 when wheat was the test crop):0, 30, 60, 90 and 120 kg N ha-1Split-plot experimental designMaterials and Methods▪ Crop N uptake ▪ Spring and harvest soil NO3-N (0 - 60 cm)▪ Apparent in-crop N mineralization (ANM, kg N ha-1)=(N uptake + Harvest NO3-N) – (N fertilizer + Spring NO3-N)▪ Apparent N fertilizer recovery  (ANFR, %)= (N uptake_F – N uptake_C / N fertilizer applied) *100%▪ Economic optimum N rate (EONR, kg N ha-1)N budget = Input – Output (based on some assumptions)Input: Spring NO3-N + ANM + N fertilizerOutput: Above-ground crop N uptakeMeasurementsMaterials and Methods▪ Proc Mixed of SAS was used▪ Analysis was conducted for individual sites and across all sites▪ Differences were considered statistically significant at P < 0.05Statistical AnalysesAbove-Ground Residue N ReturnedSimilar results were observed at individual sitesAdapted from St. Luce et al. 2016Exported in seed60-70114-122100-133 70-9058-70Preceding crop Brandon IndianHeadLacombe Lethbridge Melfort Scott All siteskg N ha-1Canola 12.0b 19.9 24.1c 15.7 7.1 21.2 16.7cFaba-seed 13.1b 19.3 19.7c 20.3 ---- 18.8 18.2bcFaba-GRM 19.5a 19.1 38.7ab 27.4 11.3 31.2 24.5aField pea 24.4a 15.7 28.4bc 18.1 11.3 27.8 20.9abLentil 19.1a 21.2 40.5a 20.2 ---- 33.6 26.9aWheat 10.7b 11.3 23.9c 17.8 11.2 19.9 15.8cField pea-GRM ---- ---- ---- ---- 11.0 ---- ----P value 0.002 NS 0.004 NS NS NS 0.0007At 0-60 cm before wheat was planted in 2011Values followed by the same letter within a column are not significantly differentSt. Luce et al. 2015Spring Soil NO3-N in 2011Apparent N MineralizationSt. Luce et al. 2016Bars with the same letter for each site are not significantly differentUnder wheat in 2011Wheat N UptakeSt. Luce et al. 2016Only N effect at LethbridgeSt. Luce et al. 2016Wheat N UptakeLinear response to NSt. Luce et al. 2016Wheat N UptakePreceding crop Intercept Slope R2Canola 88.2bd 0.55a 0.26Faba bean-seed 106.3c 0.44abc 0.13Faba bean-GRM 128.4a 0.35c 0.12Field pea 116.4b 0.40bc 0.16Lentil 123.1ab 0.43abc 0.12Wheat 81.9d 0.48ab 0.21Linear response to N across sitesAll intercept and slope values were significant (P < 0.05)Fall Soil NO3-N in 2011At 0-60 cm after wheat was harvested in 2011Nitrogen BudgetAdapted from St. Luce et al. 2016Nitrogen BudgetAdapted from St. Luce et al. 2016On average, ANM accounted for 40-60% of crop N uptake;N balance & unaccounted greater after pulsesSummary▪ Pulses can increase soil fertility and enhance soil N cycling▪ Pulse benefit depends on species, seed vs. green manure, and site-specific conditions▪ Faba bean-GRM, field pea and lentil can increase pre-plant soil NO3-N content, ANM and reduce reliance on N fertilizer inputs▪ Up to 78% of crop N uptake may be derived from N mineralized from SOM and crop residues (high labile SOM content)▪ N fertilizer recommendations should consider potential N availability; critical for reducing N surplus and N losses Funding was provided by the SAGES program of Agriculture and Agri-Food CanadaMany thanks to Mike Svistokski, Ray Smith, Randy Shiplack, Jennifer Zuidhof, Ginette Decker, Karen Terry, Lorne Nielson, Arlen Kapiniak, Kevin Willoughby, Orla Willoughby, Larry Michielson, Greg Semach, Liz Sroka, Patty Reid, Irene Murray, Randall Brandt, Duaine Messer and Lee Poppy for excellent technical support.AcknowledgementsThank you!For more information, please contact:mervin.st.luce@agr.gc.ca

Nitrogen cycling and budget in crop rotations as influenced by preceding crops and N fertilization

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Nitrogen cycling and budget in crop rotations as influenced by preceding crops and N fertilization

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