PROJECT RESULTS

Comparison of Pushing Canola at Various Stages and Swathing on Canola Yield and Quality

Applicant: 

Tom McCrea

Ag Shield Manufacturing

Benito, Manitoba  R0L 0C0  Canada

Table of Contents:

• Background and Objectives
• Procedure and Project Activities
• Results and Discussion
• Conclusions

Researcher:

Dr. Byron Irvine, Brandon Research Station, Agriculture and Agri-Food Canada

ARDI Project:

#00-429

Total Approved:

$40,000

Date Approved:

March 27, 2001

Project Status:

Completed December, 2003

Background and Objectives:

Canola is windrowed (swathed) to reduce seed loss due to pod splitting and pod drop due to wind.  Ag Shield Manufacturing has created the YIELDSHEILD^TM; a commercial device which artificially lodges the crop at or before the time of swathing.  When the crop is strongly intertwined and does not move with the wind the problem of shattering is eliminated and the crop can then be harvested with a straight cut header.  The commercial machine is capable of a high work rate on heavy crops and since the crop is not cut at the soil level has the potential of improving the yield and quality of canola.  Timing of the pushing operation and direct comparisons of this machine with windrow crop under small plot and field conditions was undertaken by Ag Shield in cooperation with Dr. Byron Irvine.

The objectives of this project were:

• Trial 1:  To determine the impact of time of pushing on yield and quality of canola relative to swathing under field scale conditions in 2001 and 2002.

• Trial 2:  To determine the impact of plant population and time of pushing on yield and quality of canola relative to swathing of the crop.

• Trial 3:  To determine the impact of crop height and lodging tolerance on the effectiveness of pushing and the correct time of pushing.

Procedure and Project Activities:

Trial 1:  Field Scale Comparison of Pushing and Swathing at Different Seeding Rates - 2001

Conquest, Roundup Ready^TM canola was seeded May 16 at 4.4 and 6.2 kg ha^-1 of seed for early and late pushing and a single seeding rate of 6.2 kg ha^-1 for the swathing comparison.  Plots were 18.3 m wide and 500-700 m in length.  The soil at this site was a Newdale clay loam.  The plots were pushed August 8 and August 16.  The plots were pushed with a 9.1 m wide commercial pusher and swathed 7.62 m wide commercial swather on August 16.  Full swaths were combine harvested September 10 and 12; areas harvested determined using a combine mounted area meter and the grain harvested from each plot weighed using a commercial grain cart to the nearest 20 kg.  This site had significant levels of sclerotinia which made determination of maturity and thus swathing time difficult.  The first pushing date was about the time of the start of seed color change in the more advanced areas of the field and the second date at about 40-50% brown seed on the main stem.

Samples of kinked and non kinked plants and sclerotinia and non sclerotinia infected plants were taken from selected plots and seed weight determined.

Trial 1:  Field Scale Comparison of Swathing vs. Pushing - 2002

Four fields were selected and 3-5 replicate randomized complete block trials were established.  The treatments were pushing about 7 days prior to predicted swathing, and pushing and swathing on the same day.  Site one had Clearfield canola, site two was Roundup Ready^TM, site three was Invigor and site four was Nexera canola.  Crops were harvested near the end of September when the producer deemed the crop ready and the material was dry.

Trial 2:  To Determine the Impact of Plant Population and Time of Pushing on Yield and Quality of Canola Relative to Swathing of the Crop

Invigor2273 canola was planted into cereal stubble (zero till) with a disc seeder.  Planting was delayed until June 6 due to wet soil conditions.  The soil at this site was a Newdale clay loam.  Plots were seeded with a disc seeder into wheat stubble 6 rows 30.5 cm apart and 10 m long with 8 replications.  The design of the trial was a complete factorial with seeding rates and time of pushing as the main factors.  Swathing occurred at only 2 dates and direct harvest only at the time of harvest of the pushed or swathed plots.  The target plant populations were 70 and 140 plants m^-2.  The plots were grown with less than 60 kg/ha of total nitrogen to simulate a dry growing season when plants were less vigorous and pushing more difficult.  The crop was pushed at 5 dates, swathed at 2 dates and direct harvested on one date.  Fifty pods were taken at the time of swathing or pushing and frozen.  If differences in yield occurred these were to be examined for stage of development.

Trial 3: To Determine the Impact of Crop Height and Lodging Tolerance on the Effectiveness of Pushing and the Correct Time of Pushing

Canola was planted in 6 row plots (1.8 m x 20m) into cereal stubble (zero till) with a disc opener on May 14, 2002.  Four varieties of Roundup Ready canola were planted at 120 seeds/m² (~5 l/ac).  The trial was a 3 replicate complete factorial with 6 pushing dates and a single swathing date for each variety.  These varieties differed in maturity and lodging resistance.  Pushing commenced for both trials on August 1, approximately 18 days before optimal swathing time for the majority of the varieties and continued up to time of swathing.  Pushing was done by an Ag Shield manufactured plot pusher.  Swathing was done at 20-30% seed color change.  All plots were harvested using a plot combine.

Data collected:  plant numbers, moisture content of the seeds in the pod at the time of pushing, pushing ease (1-5).  Ratings were also done on the number of stems in a given area that were kinked vs. bent.  To document changes in staging at each pushing date and at the time of swathing pictures were taken of each plot.  For each plot yield, dockage, moisture content, green seed and oil content was collected.

Results and Discussion:

Trial 1 - 2001

Early pushing and swathing had similar yields and these were 6% lower than the later pushed canola (at the same time as swathing).  However, these were not statistically different (Table 1).  Seed size was the same for early and late pushing and both of these were greater than the swathed crop by over 20%.  This should have translated into increased yields but uncertainty in measuring yields of the swathed plots resulted in an inability to determine if this is an actual difference.  Oil content of the swathed crop was greater than that of the early pushed crop and the oil contents were similar at the late pushing date and the swathed crop.  This is likely due to increased shattering losses at the late date eliminating some of the sclerotinia infected seeds at the later date.  Improvements in plot layout will be implemented in 2002 and only one seeding rate used.  It is clear that when there is uneven ripening in the field the decision to push is much easier than the decision to swath.

Table 1.  Effect of Seeding Rate and Stage of Crop at Pushing on Seed Yields and Seed Quality at Site One: Trial 1 – 2001

While lower seeding rates tend to create larger stalks which kink easier, the level of kinking does not reduce seed size.  Factors such as the direction in which the crop was leaning had a much larger impact on the ease of pushing than did seeding rate.  Kinking of the stem did not affect seed weight in this trial (kinked stems 3.451 vs. 3.482 grams per 1000 seeds). 

Trial 1 - 2002

Canola yield at site one was about 1% greater when pushing occurred at the same time as swathing and 4% lower when pushing occurred one week earlier than swathing (Table 2).  Oil content was identical when the crop was pushed on the same day as swathing occurred.  This site had yields of over 40 bu/ac and very little of the crop sprang back after pushing.

At site two, canola pushed a day earlier than swathing occurred yielded 13% more than canola which was swathed (Table 2).  However, pushing one week earlier than swathing caused an 11% yield reduction.   Oil contents did not differ.  Very little of the crop sprang back but the pushed plots had greener stalks.

Table 2.  Yield and Oil Content of Replicated Field Scaling Pushing Trials: Trial One - 2002 

Canola yields and oil contents were identical for pushed and swathed treatments at site 3 (Table 2).  Almost no crop sprang back. 

Site four had a very thin stand and some of the canola sprang back after being pushed, resulting in a non significant reduction in yield of 10% (Table 2).  Oil content of the pushed stand was numerically greater but this was not statistically significant.

Trial 2

While there were numerical differences in yield due to time of pushing or pushing vs. swathing these were not related to pushing time in a consistent way and yield differences could not be detected (Table 3).  This was despite the fact that seed weights increased as the time of pushing was delayed; with an 8% increase from date 1 to date 5.  Green seed numbers were significantly different but were due more to random chance than time of pushing as dates 1, 2 and 5 had more green seeds than dates 3 and 4.  Oil content did not differ when plots were pushed or swathed at similar times.  There was an increase in oil content of 1.8% from early to late pushing; however it is unclear as to the significance of this since there was less than a 0.5% difference between August 27 and Sept 4. 

Higher plant populations made pushing easier at any pushing date.  Pushing became more difficult as the season progressed with plants pushed near the time of normal swathing having a tendency to bounce back and thus be susceptible to shattering.  Since the goal of pushing is to prevent movement of the pods due to wind it is important that plants remain close to the soil surface and thus pushing prior to the date of normal swathing is desirable.

Table 3.  Impact of Seeding Rate and Time of Pushing of Canola Yield and Quality - 2001