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Organic Field Crop Production and Marketing in North Carolina

     
Organic No-till Roller System
Alternative Grain Crops
2011 Organic Canola Seeding Rate Report

Fall 2010 – Spring 2011
Chris Reberg-Horton and Carrie Brinton

Canola is a fairly new and promising crop to North Carolina.  There is market demand for organic canola, and organic farmers are looking to diversify their crop rotation.  We planted 3 canola varieties at 5 seeding rates – 3, 6, 9, 12 and 15 lb/acre.  Conventional seeding rates are typically between 3 and 6 lbs per acre.  A major concern for organic producers is weed management so our bias is often to use as much seed as possible to aid competition with weeds.  Our goal was to investigate whether higher seeding rates led to negative consequences such as higher disease pressure due to less airflow or increased lodging.  No pre- or post-herbicides were applied during the growing season; however, we did use a desiccant at harvest in Salisbury to prevent shattering until we could arrive with the combine.  This study was planted at Cherry Research Farm in Goldsboro, NC and Piedmont Research Station in Salisbury, NC.

Table 1.  Field management throughout the season.

 

Goldsboro, NC

Salisbury, NC

 

Date

Rate

Date

Rate

Planting Dates

November 2, 20101

 

September 20, 2010

 

Fall N (lb/A)

November 20, 2010

32

-

*

Spring N (lb/A)

February 28, 2011

83

February 18, 2011

58

Spring S (lb/A)

February 17, 2011

26

February 18, 2011

17

Stand Counts

March 9, 2011

 

March 7, 2011

 

Dessicated with Paraquat

-

-

June 2, 2011

1

Harvest

June 3, 2011

 

June 20, 2011

 

*No pre-plant N was applied in Salisbury because these fields receive dairy lagoon waste on a regular basis.  Experience has proven that fall N applications tend to cause lodging in crops. 


Table 2.  Harvest data for seeding rates across all varieties.

Goldsboro, NC

Salisbury, NC

Rate

Moisture

Yield*

Yield**

Test Weight

Moisture

Yield*

Yield**

Test Weight

%

lb/ac

bu/ac

lb/bu

%

lb/ac

bu/ac

lb/bu

3

7.12

1933

32

54.4

4.32

3981

66

56.1

6

5.98

2215

37

58.6

3.78

4145

69

55.9

9

5.21

2377

40

58.5

5.28

4267

71

56.8

12

6.11

2167

36

55.3

4.37

3961

66

55.8

15

6.13

2227

37

57.5

4.11

4045

67

55.4

ANOVA

------------------------------------------------      Prob > F    ----------------------------------------------------

rate

0.12

0.10

NS

NS

NS

NS

NS

linear

0.25

.14

 

 

 

 

 

 

 

quadratic

0.03

.06

 

 

 

 

 

 

 

* Yield data corrected to 8.5% moisture. 
**Yield calculated at 60 lb/bushel.

Seed size varies among these varieties.  Flash has much smaller seed than Virginia, with 33% more seed per pound.  Hornet is also smaller than Virginia, although only 12% more seed per pound. 

The canola crop in Salisbury reached growth stage 2.6 – 2.7 before the first night at 25°F in early November.  The Goldsboro site was originally planted in mid-October, but due to problems with the planter, needed to be replanted.  There were a couple nights at 31°F shortly after planting, but temperatures did not fall below 25°F until 5-WAP. 

Moisture – There was no significant moisture difference among varieties or seeding rates in Salisbury where we applied Paraquat to desiccate the crop prior to harvest.  However, in Goldsboro, where desiccant was not applied, moisture differences were observed across seeding rates.  The lowest moisture was at the 9 lb/ac seeding rate, while the highest moisture was at the lowest seeding rate.  At the lowest seeding rate we observed late emerging branches that filled in the light gaps in the canopy.  The late branches were greener at harvest than the bulk of the crop and likely contributed to the higher moistures.

In Goldsboro, a small difference in moisture due to variety (p = 0.07, data not presented) was detected. 
We did not collect data on varietal maturity, but visual observation at both locations throughout the spring indicated Virginia flowered first and dried down earlier, while Flash was still a bit green when we harvested.  Data from the 2009 National Winter Canola Variety Trial showed maturity of Virginia, Flash and Hornet all within 6 days of each other at the Virginia, Georgia and Alabama locations.

Yield – No varietal differences were detected.  No significant differences were observed in yield across seeding rates in Salisbury, however there were significant differences in Goldsboro.  In Goldsboro, there was a large yield gap between the lowest seeding rate and all the other seeding rates.  The 9 lb/acre seeding rate produced the highest yields at both locations.  Yields were higher at Salisbury for each seeding rate, 44% - 51% greater than Goldsboro. 

Seeding rate and moisture graph

canola yield and seeding rate graph

Conclusions
So far we have seen no evidence that higher seeding rates are a problem for diseases or lodging.  However, this is only one year of data and disease pressures were low on winter crops this year.  Extreme caution is needed with one year of data, but so far 9 lbs of seed appears to be an appropriate seeding rate.  We are attempting to plant this study on weedy sites this year to do a better job of quantifying the impact increased seeding rates has on weed control. 

This project has been generously funded by the NC Tobacco Trust Fund Commission.
Any opinion, finding, conclusion, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view and policies of the North Carolina Tobacco Trust Fund Commission.

TTF logo

This project has been generously funded by the NC Tobacco Trust Fund Commission.
Any opinion, finding, conclusion, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view and policies of the North Carolina Tobacco Trust Fund Commission.

 

 

 

     

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