The Changing Face Of Manitoba Crop Rotations Doug Wilcox, Manager, Program Development - Insurance Manitoba Agricultural Services Corporation Presentation to the Manitoba Agronomists Conference U of M, Winnipeg, Dec 12, 2012
The problem In recent years more and more Manitoba producers are increasingly willing to face the additional risk resulting from shorter than recommended crop rotation break periods with the objective of improved short-term revenue potential.
Changing Face. The extent and impact of this changing face of crop rotation on several major annual spring crops grown in Manitoba has been quantified over the years using annual crop acreage and yield records reported by AgriInsurance clients to MASC
Data Analyzed MASC has been collecting client information for decades and the acreage of crops insured by MASC in most years is over 85 per cent of all annual crop acres grown in Manitoba, making the database very representative and useful.
Data Analyzed All summary results are based on MASC database field histories from fields 120 acres or larger tracked over the relevant periods. Analysis is limited to larger fields as MASC does not track field positions within quarter sections.
Some Historical Analysis 16%+ MASC wheat yield data, 1982-93 8%+ 11%+ Bourgeois, L. and Entz, M. H. 1996. Influence of previous crop type on yield of spring wheat: Analysis of commercial field data. Can. J. plant sci. 76: 457459.
Observations Rotational benefits recorded in small plot trials are also observed in commercial crop production. Results should encourage producers to grow spring wheat in sequence with noncereal crops.
Some Historical Analysis Wheat yield deviation 1997-2006 Avg 24 bu/ac diff between best & worst stubble yield D. Wilcox. 2008. Rotation still has a big influence on yield. Grainews March 10, 2008 pg 6-7.
Some Historical Analysis Canola yield deviation 1997-2006 10 bu/ac diff between best & worst stubble yield D. Wilcox. 2008. Rotation still has a big influence on yield. Grainews March 10, 2008 pg 6-7.
Observations For both wheat and canola, the same four types of stubble at planting resulted in the highest average yields: White pea beans, Potatoes, Fababeans, Grain corn Cause not determined high residual fertility? Fall rye stubble resulted in lowest yields.
Observations Wheat on wheat Average yield 90% of average. Wheat on cereals generally below avg ylds Canola on canola Average yield 93% of average. Canola on broadleaved crops generally below average yields Below average yields when planted on alfalfa hay stubble and fallow fields Alfalfa allelopathy? Fallow lower fertility?
Some Stubble Analysis Fields A. Kubinec 2009. Canola on canola your fields say it doesn t work. Yield Manitoba, Feb 2009, pgs 22-23 & D. Wilcox 2000. Manitoba Crop Rotation Information. Yield Manitoba, Feb 2000, pg 14
Main stubble @ planting Canola Sp Wheat (53%) Sp Wheat Canola (58 %) Soybean Sp Wheat (25%), Oat (17%), Canola (10%) G Corn G Corn (13%), Wheat (12%), Canola (11%) Navy Bean Sp Wheat (44%), Canola (16%) Field Pea Sp Wheat (59%) Flax Sp Wheat (54%) Barley Canola (35%), Sp Wheat (23%)
Cereals less crop on crop Crop 1994-98 vs 1998-07 Sp wheat 30% vs 11% Barley 15% vs 10% Oat 9% vs 4% Canola 2% vs 3% Other crops not done in 98 or NSD
Some Stubble Analysis Yields A. Kubinec 2009. Canola on canola your fields say it doesn t work. Yield Manitoba, Feb 2009, pgs 22-23 & D. Wilcox 2000. Manitoba Crop Rotation Information. Yield Manitoba, Feb 2000, pg 14
Best Crop on Crop Yields
Observation Canola on Canola yield decline Crop 1994-98 vs 1998-07 Canola 88% vs 82% Cereal crops not much change
Note These are average observations not recommendations Similar observations are more likely to be obtained in a particular farm operation if Significant yield difference & High frequency of farmers reporting result
Recently took analysis of observations to next level Moved from stubble (one year) to break period analysis (0, 1yr,. 4+yrs)
Recent Analysis Average % acres by break period for major crops 2000-2010 D. Wilcox 2012. The crop rotation break interval effect in Manitoba. Yield Manitoba, Feb 2012, pgs 10-13.
Good Break Periods Greater than 50% of fields with 4 or more years between plantings
Tight Break Periods Red - Greater than 10% of fields with 0 years Green Approx ½ acres with <=1 year
Recent Analysis Average % Yield deviation by break period for major crops 2000-2010 D. Wilcox 2012. The crop rotation break interval effect in Manitoba. Yield Manitoba, Feb 2012, pgs 10-13.
Textbook Responses 4-0 Yield Diff Flax 6 bu/ac Field Peas 8 bu/ac Oats 18 bu/ac
Almost Textbook Responses 3-0 Yld Diff Barley 9 bu/ac Grain Corn 19 bu/ac Canola 5 bu/ac RS Wheat 6 bu/ac
Cause of 4 th Year decline Natural data variability (statistical significance not determined) or confounding unidentified variables (management, regions, weather) Perhaps if choosing to grow these crops less frequently these producers have less experience/less interest in these crops and in turn are less successful?
Asymetric Responses Non-oil sunflowers & soybeans bounceall-over Perhaps b/c limited data (sunf) and limited experience (soy)
Recent Analysis Note that even textbook crops can be nontextbook in some years.. Flax 2004 D. Wilcox 2012. The crop rotation break interval effect in Manitoba. Yield Manitoba, Feb 2012, pgs 10-13.
Canola Lots of recent interest in canola rotations Certainly tight rotations are increasing
1.2 Effect of Crop Rest Periods on Canola Yield 1 0 1 2 3 4 0.8 Yield (tonnes/ac) 0.6 0.4 0.2 0 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Year
Other crops are also at risk
MASC "No-Break" Rotation Summary (2000-2010) DESCRIPTION % Field # % Of Avg Yield GRAIN CORN 13.2% 89% RED SPRING WHEAT 11.6% 90% SOYBEANS 11.6% 97% BARLEY 11.3% 88% OATS 4.7% 85% CANOLA 3.8% 87% FLAX 0.4% 80% NON-OIL SUNFLOWERS 0.2% 101% FIELD PEAS 0.1% 88%
MASC Data "No-Break" Rotation Summary (2011) DESCRIPTION % Field # % Of Avg Yield GRAIN CORN 5.7% 87% RED SPRING WHEAT 2.1% 79% SOYBEANS 16.0% 94% BARLEY 6.0% 85% OATS 9.3% 76% CANOLA 13.0% 88% FLAX 0.8% 112% NON-OIL SUNFLOWERS N/A N/A FIELD PEAS N/A N/A
Crop Insurance. MASC has the authority to deny coverage for improper rotations under the contract: 5.01 Uninsured Causes. This Contract does not insure against any loss or damage, resulting from one or more of the following:.(j) improper crop rotation,
Crop Insurance Regardless of the cause, MASC has insurance mechanisms to incorporate the negative crop production experience of producers when they have lower than average yield potential (e.g. IPI system) and/or higher losses than normal (e.g. Discount/Surcharge system).
Summary comments MASC client records confirm that for many crops there is a positive yield response associated with increasing crop rotation break intervals in commercial fields. MASC client records also demonstrate that in the real world the positive crop rotation yield response is not always text-book and can vary by crop, break interval, and year.
The challenge The challenge faced by those making field rotation decisions is to use MASC observations and other extension information to continually re-determine the 'best' crop rotation for each field according to individual problems, circumstances and commodity prices.
Thank-You dwilcox@masc.mb.ca