Manitoba Management Plus Program

Canola on Canola - Your Fields Say it Doesn't Work

by Anastasia Kubinec, Oilseed Business Development Specialist, MAFRI

There was a lot of canola in Manitoba in 2008 — almost three million acres, our largest planting ever. For 2009, canola still pencils out as a good crop to grow. So maybe you’re thinking that your 2008 field of canola, should be canola again in 2009.

Hold that thought for a moment.

An excellent free “risk management” resource from Manitoba Agricultural Services Corporation (MASC) may add new insight to your cropping choices. The MASC database, created with data submitted from your annual harvest reports, holds thousands of real-life yield responses across the province of how crop A planted on stubble B (or C, D, E, F) yielded.

This can help reduce risk on your operation is by removing some of the guessing game over how canola on canola might yield, or whether wheat on canola would be better.

The information from the database is already available for 1994 to 1998, and offers a snapshot of the impact of the previous years stubble type on present year crop yields. Looking at information
on the MASC website, “Crop On Crop — How Common?”, it shows canola yielded only 88% of the average in those years when planted on canola stubble. Compared to other crop choices, the canola-on-canola rotation had the poorest yield potential.

The data is older and may not be as relevant to present-day varieties with better hybrid yield potentials. To take a look of how crop yields are responding to stubble today, the table has been updated and expanded with the assistance of the Manitoba Agriculture, Food and Rural Initiatives (MAFRI) crop specialists at the Crops Knowledge Centre.

The longer-term and more current database (from 1998 to 2007) tells the same story (Table 2). Canola planted on canola stubble results in an 83 per cent potential yield, a five per cent decline from the 1994 to 1998 data set. We could speculate that the further yield decrease may be due to increased disease pressure, such as blackleg, but do not know for sure, as yield-limiting factors are not a part of the information collected in the MASC harvest reports.

In brief, Table 2 is a crop rotation chart, one planting season at a time. The table provides the potential yield of a crop on stubble combination, as compared to the average yield for the planted crops on all stubble types in Manitoba from 1994 to 2007. The table includes both the major and minor acreage crops currently being grown in Manitoba; forage crop information has not been presented. Personal common sense should also be used when reading the table. Many crops are presented, but some crops are better suited to specific areas and regardless of rotation will not perform in other areas. The table and all of the combinations are to provide interested producers with an additional tool to determine crop sequences and their yield risks.

The MASC database also provides information on the frequency that a specific crop on stubble rotation is practised (Table 1). This information on “how many farmers actually do this” can indicate what works by chance and what sequences enjoy good success. For example Hard Red Spring wheat (HRS) planting on navy bean stubble looks like a fantastic rotation option with the HRS yielding 124 per cent over average HRS yields, but only one per cent of farmers reported using that rotation sequence. With that low of frequency, you may not want to put all your HRS on navy bean land, but this may be an idea to try one or two fields to find out if those results work on your farm.

Cases where there are a yield benefit (over 100 per cent of average) in combination with a high frequency of farmers using the crop on stubble sequence like flax on HRS stubble or HRS on canola stubble, are more likely to also be reflected on your farm.

In summary, if you are wondering how a crop will work on last year’s stubble, this spreadsheet may be of value to you and could give you some confidence in trying out a new crop sequence combination or reinforce some of the trends you see on your own farm. This is a very limited view of what happens, but with 15 years of information from actual fields, it does provide some potential combinations that consistently do not work. Avoiding them could be a simple step towards improving your yields.

This article originally appeared in the 2009 edition of Yield Manitoba.

Previous Crop (stubble) distribution (%) of large acreage fields (120 acres or more) sown to major field crops in Manitoba (1998 - 2007)

Previous Crop	Crop Planted
	Winter Wheat	Spring Wheat	Barley	Oats	Canola	Flax	Peas	Soybeans	Corn
Winter Wheat	1	NSD	4	3	4	5	8	6	3
Spring Wheat	2	11	23	21	53	54	59	25	12
Barley	3	2	10	6	12	11	10	4	4
Oats	4	3	6	4	9	9	5	17	4
Canola	51	58	35	35	3	5	4	10	11
Flax	1	7	5	5	2	NSD	1	2	NSD
Peas	2	4	2	1	NSD	NSD	NSD	NSD	NSD
Soybeans	NSD	2	2	7	1	1	NSD	9	7
Corn	NSD	NSD	NSD	1	NSD	NSD	NSD	4	13

* NSD - No Sufficient Data

Yield Response (% of 1998 - 2007 average) of major Manitoba crops sown on large (120 acre or more) fields of various previous crops (stubble) in rotation

Previous Crop	Crop Planted
	Winter Wheat	Spring Wheat	Barley	Oats	Canola	Flax	Peas	Soybeans	Corn
Winter Wheat	76	NSD	100	102	94	105	98	102	79
Spring Wheat	91	90	101	101	103	102	102	107	96
Barley	91	92	88	91	100	99	97	92	82
Oats	97	93	91	85	95	97	93	104	101
Canola	104	103	105	104	83	90	93	99	98
Flax	102	98	104	102	98	NSD	79	58	NSD
Peas	90	100	104	105	101	NSD	NSD	NSD	NSD
Soybeans	NSD	109	98	89	84	NSD	NSD	72	93
Corn	NSD	NSD	NSD	107	NSD	NSD	NSD	84	92

* NSD - No Sufficient Data

Crop On Crop - How Common?

Previous crop (stubble) distribution (%) of large acreage fields (>120 acres) sown to the major field crops in Manitoba during the period 1994-1998.

Stubble Crop	Crop Sown
	RS Wheat	Barley	Oats	Argent. Canola	Flax	Field Peas
	Percentage of Sown Acreage
All Wheats	30	40	32	68	72	75
Barley	4	15	7	14	11	10
Oats	2	3	9	6	5	4
Canola	44	30	30	2	8	4
Flax	11	6	13	4	1	3
Field Peas	3	2	1	1	0	0
Other	6	4	8	5	3	4

Type on Type - How Common?

Previous crop class (stubble) distribution (%) of large acreage fields (>120 acres) sown to the major field crops in Manitoba during the period 1994-1998.

Stubble Crop	Crop Sown
	RS Wheat	Barley	Oats	Argent. Canola	Flax	Field Peas
	Percentage of Sown Acreage
Cereal Crops	39	60	52	90	90	90
Broadleaved Crops	61	40	48	14	11	10

Crop Rotation Bushel Yields

5-year (1994-1998) average yield of major Manitoba crops sown on large (>120 acre) fields of various previous crops (stubble) in rotation.

Crop Sown	Previous Crop (Stubble)
	RS Wheat	Barley	Oats	Arg. Canola	Flax	Field Peas
	Five Year Average Yield (Bu/Ac)
RS Wheat	31	33	34	36	35	37
Barley	60	52	56	62	64	64
Oats	81	74	71	88	87	82
Arg. Canola	28	28	29	25	29	32
Flax	21	21	20	19	14	NSD*
Field Peas	33	33	30	29	26	NSD*

* NSD - No Sufficient Data

Crop Rotation Relative Yields

Relative yield response (% of 1994-1998 average) of major Manitoba crops sown on large (>120 acre) fields of various previous crops (stubble) in rotation.

Crop Sown	Previous Crop (Stubble)
	RS Wheat	Barley	Oats	Arg. Canola	Flax	Field Peas
	Relative Yields (% of Average)
RS Wheat	90	98	99	106	103	108
Barley	101	88	97	105	107	107
Oats	99	90	87	108	107	100
Arg. Canola	100	101	103	88	104	113
Flax	102	102	101	92	69	NSD*
Field Peas	101	101	93	89	82	NSD*

* NSD - No Sufficient Data