Legume Crops Grown in Rotation Enhance Canola and Barley Productivity in Western Canada

Legume crops grown in rotation enhance canola and barley productivity in western Canada John O’Donovan, Agriculture & Agri-Food Canada, Lacombe, Alberta

Collaborating scientists • Cynthia A. Grant, Robert E. Blackshaw, K. Neil Harker, Eric N. Johnson, Yantai Gan, Guy P. Lafond, William E. May, T. Kelly Turkington, Newton Z. Lupwayi, F. Craig Stevenson, Debra L. Mclaren, Mohammad Khakbazan, Elwin G. Smith •

Background • High costs of fertilizer in western Canada have generated interest in alternative N sources • Legume crops have the potential to reduce the requirement for inorganic N in subsequent crops, particularly cereals • Little or no research has been conducted with hybrid canola (Brassica napus L.), a major western Canadian cash crop, and a strong consumer of nitrogen

Background • Barley is commonly grown in rotation with canola and malting varieties usually predominate • However, less than 25% of the barley grown is usually accepted for malting grade annually with excess protein (>125 g kg-1) being a frequent cause for sample rejection • Some growers are reluctant to grow malting barley in rotation with legumes since doing so may contribute to excess protein concentration

Objective • To determine the effect of different rotational crops (including legumes) established in 2009 on yield and oil concentration of hybrid canola grown in 2010, and yield and protein concentration of malting barley grown after canola in 2011

Western Canadian Study Locations Locations Western Canadian Study 60ยบ N Lat. Fort Vermillion

Saskatchewan

Saskatchewan Alberta

Alberta

Manitoba

Manitoba Canadian Shield

Beaverlodge Vegreville Lacombe Scott

Lethbridge

49ยบ N Lat.

Swift Current

Indian Head

USA

Brandon

Gray Dark Gray Black Dark Brown Brown

Crop sequence • 2009: Field pea, lentil, faba bean, canola and wheat harvested for seed, and faba bean grown as a green manure were direct-seeded to provide crop residues for treatments in 2010 and 2011 • The legumes received little or no N; wheat and canola were fertilized according to the soil test recommendation • 2010: Hybrid canola was seeded across the experimental area • 2011: Malting barley was seeded across the experimental area • 2010 and 2011: Nitrogen (urea) was applied at 0, 30, 60, 90, 120 kg ha-1

Experimental design in 2010 (canola) and 2011 (barley) • The experiment was a split-plot with 4 replicates • The 6 crop residues (established in 2009) were assigned to main plots, and 5 inorganic nitrogen rates were assigned to sub-plots

Data analysis • Data were analyzed using PROC MIXED of SAS • Crop residues and N rate were considered as fixed effects • Locations, replicates within locations, and their associated interactions with fixed effects were considered as random effects, allowing for general conclusions and recommendations to be made on the relative merits of the treatments • Differences were deemed significant at P < 0.05

P values for the effect of crop residue, N rate and their interaction on canola and barley agronomic variables Crop residue (C) Crop Canola (2010)

Barley (2011)

Variable

N rate (R)

CxR

P values

Yield

<0.001

<0.001

0.995

Oil

<0.001

<0.001

0.968

Yield

<0.001

<0.001

0.925

Protein

0.005

<0.001

0.999

Effect of crop residue (averaged across N rates) on canola yield and oil concentration in 2010 Crop residue

Canola yield (kg ha-1)

Canola oil (g kg-1)

Wheat

2289

469

Faba bean (GRM)

2906 (27%)*

463 (-1%)*

Faba bean (seed)

2346 (NS)

471 (NS)

Field Pea (seed)

2517 (10%)*

467 (NS)

Lentil (seed)

2521 (10%)*

466 (NS)

Canola (seed)

2097 (-8%)*

470 (NS)

*Indicates significantly different from wheat residue (p < 0.05) NS indicates not significantly different from wheat residue (p > 0.05)

Response of canola yield to crop residue kg ha N and N rate 90 Lentil residue = 2760 kg ha -1

-1

Pea residue = 2690 kg ha-1 120 kg ha-1 N Wheat residue = 2660 kg ha-1

Response of canola oil concentration to crop residue and N rate

Effect of crop residue (averaged across N rates) on barley yield and protein concentration in 2011 Crop Residue

Barley yield (kg ha-1) Barley protein (g kg-1)

Wheat

4270

113

Faba bean (GRM)

4872 (14%)*

117 (3%)*

Faba bean (seed)

4460 (NS)

112 (NS)

Field Pea (seed)

4508 (6%)*

114 (NS)

Lentil (seed)

4579 (7%)*

116 (3%)*

Canola (seed)

4431 (NS)

113 (NS)

*Indicates significantly different from wheat residue (p < 0.05) NS indicates not significantly different from wheat residue (p > 0.05)

Response of barley yield to crop residue kg ha N and N rate 90 Lentil residue = 5010 kg ha -1

-1

Pea residue = 5060 kg ha-1 120 kg ha-1 N Wheat residue = 5020 kg ha-1

Response of barley protein concentration to crop residue and N rate

Conclusions • Compared to wheat, all legume crops (except faba bean grown for seed), produced higher canola and barley yields • Faba bean green manure produced the highest yields but this would be uneconomical due to lack of crop revenue in the green manure year (replacement for fallow??)

• In western Canada, annual legume crops such as field pea and lentil would most likely be grown as cash seed crops rather than as a green manure

Conclusions • There was a 10% increase in hybrid canola yield (2010) and 6-7% increase in barley yield (2011) when field pea or lentil were the preceding crops compared to the more common wheat-canola-barley rotation • Basing N management on a target yield, 25% less fertilizer N was required to maintain a given canola or barley yield when canola and then barley followed field pea or lentil rather than wheat • The lowest canola yield (-8%) occurred when canola was grown on canola residue – no disease pressure evident • The legume crops increased yield without having a major negative impact on canola oil or barley protein concentration – more likely with inorganic N

Acknowledgements â&#x20AC;˘ Funding for this project was obtained under Agriculture & AgriFood Canadaâ&#x20AC;&#x2122;s Canola/Flax Cluster and Barley DIAP. Industry partners involved in the Cluster and DIAP were the Canola Council of Canada, Alberta Canola Producers Commission, Saskatchewan Canola Development Commission, Manitoba Canola Growers Association, Alberta Barley Commission, RAHR Malting, and the Barley Malting and Brewing Research Institute. We thank Larry Michielsen, Greg Semach, Jennifer Zuidhof, Liz Sroka, Patty Reid, Irene Murray, Randall Brandt, Orla Willoughby, Randy Shiplack, Lee Poppy and Mike Svistovski of Agriculture & Agri-Food Canada for excellent technical support; Lori Oatway of Alberta Agriculture & Rural Development for the NIRS barley protein analysis