The Changing Face Of Manitoba Crop Rotations€¦ · trials are also observed in commercial crop...
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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
Transcript of The Changing Face Of Manitoba Crop Rotations€¦ · trials are also observed in commercial crop...
The Changing Face Of Manitoba Crop Rotations
Doug Wilcox, Manager, Program Development - InsuranceManitoba Agricultural Services Corporation
Presentation to the Manitoba Agronomists ConferenceU 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…
MASC wheat yield data, 1982-93
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.
16%+
11%+8%+
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 non-cereal 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…
D. Wilcox 2012. The crop rotation break interval effect in Manitoba. Yield Manitoba, Feb 2012, pgs 10-13.
Average % acres by break period for major crops 2000-2010
“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
Average % Yield deviation by break period for major crops 2000-2010
Recent Analysis…
D. Wilcox 2012. The crop rotation break interval effect in Manitoba. Yield Manitoba, Feb 2012, pgs 10-13.
4-0 Yield Diff Flax – 6
bu/ac Field Peas
– 8 bu/ac Oats – 18
bu/ac
“Textbook” Responses…
3-0 Yld Diff Barley – 9
bu/ac Grain Corn
– 19 bu/ac Canola – 5
bu/ac RS Wheat –
6 bu/ac
“Almost Textbook” Responses…
Cause of 4th 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?
Non-oil sunflowers & soybeans “bounce-all-over”
Perhaps b/c limited data (sunf) and limited experience (soy)
“Asymetric” Responses…
Recent Analysis
D. Wilcox 2012. The crop rotation break interval effect in Manitoba. Yield Manitoba, Feb 2012, pgs 10-13.
Note that even textbook crops can be non-textbook in some years.. Flax 2004
Canola…
Lots of recent interest in canola rotations…
Certainly tight rotations are increasing
0
0.2
0.4
0.6
0.8
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1.2
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
Yie
ld (t
onne
s/ac
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Effect of Crop Rest Periods on Canola Yield
0 1 2 3 4
Other crops are also at risk…
MASC "No-Break" Rotation Summary (2000-2010)
DESCRIPTION % Field # % Of Avg YieldGRAIN 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 YieldGRAIN 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/AFIELD 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).
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.
Summary comments…
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.
