1995
REPORT OF THE CONSERVATION TILLAGE PRODUCTIVITY |
Center-
LaSalle, Manitoba
Keith Murphy, RAg.
1995 was the first growing season for the Conservation Tillage Productivity Center- LaSalle (CTPC), with a full compliment of tests and demonstrations in place. During 1994, wheat and flax were grown and 1.5 acre blocks were marked out.
FALL 1994 TREATMENTS
The fall 1994 treatments consisted of:
Burn and Work
The fall treatments were completed, in spite of wet ground conditions in the fall of 1994.
SEEDING 1995
Seeding of the 1995 trials took place in late May under very hot air temperatures, but with good soil moisture conditions. The relative success of the seeding operations varied with implement. Seeding with the airseeder resulted in an acceptable seed bed, and harrowing after the airseeder improved the seedbed conditions. The disker resulted in increased soil disturbance as compared with the airseeder. Depth of seed placement, especially under minimum and zero till conditions, was more difficult with the disker, as there were difficulties in penetrating the soil surface. This resulted in seed being closer to the surface than recommended. The Concord direct seeder, fitted with Anderson boots with fertilizer spikes, did not perform well under the seeding conditions in 1995. The soil did not close behind the seed boot, which resulted in a significant amount of uncovered seed in the furrow. In order to attempt to compensate for the lack of soil covering behind the boot, the direct seeding trial was split into two treatments- one was left as is, the other was harrowed twice in an attempt to close the furrow. However, since the fertilizer spike on the Anderson boot is set to penetrate 3.5 inches deep, relatively large chunks of soil were brought to the surface, and were not broken down by the two harrowing operations. The choice of the Anderson boot was made on the basis of experience in red river clay soils. The addition of the fertilizer spike seemed to cause most of the problems with seed bed establishment.
1995 GROWING SEASON
After seeding, the growing conditions could best be categorized as drought. No significant rainfall was recorded until late August. The high soil moisture conditions in the spring resulted in the production of a harvestable crop, although yields were well below average.
1995 RESULTS
l. Residue Management
One objective of the CTPC is to examine the effects of different agronomic practices on the amount of residue cover. The goal of the residue management trials was to examine the % cover that resulted from each operation. 30% cover was used as the threshold for soil conservation. Results of residue cover after seeding into wheat stubble appear in Figure l. The results indicate that the burn and work fall treatment on the wheat stubble reduced the amount of trash cover on the field. Prior to spring seeding, there was 33.5% trash cover. After seeding, 15% or less of the original cover remained. The conventional fall tillage treatment left more residue prior to seeding, but the post-seeding residue levels approached the 30% minimum threshold. Minimum till and zero till treatments maintained high residue levels both before and after seeding.
The maintenance of crop residue after production of a low residue-producing crop such as flax is an important component to the Residue Management research at the CTPC. Flax was used as a model for a low-residue producing crop. Figure 2 illustrates that preseeding levels of residue cover were sufficient to prevent soil erosion. However, there was less than 20% residue cover after seeding with all seeders. Differences among the seeders were evident. The disker left very low levels of residue after seeding, followed by the airseeder and the direct seeder. The addition of a harrow operation to the direct seeder resulted in less residue cover. The low levels of residue left after seeding on the flax stubble indicate that additional work is required in order to determine the best method of seeding into low residue land. In order to better examine this trend, a low disturbance direct seeder will be added to the seeder array in 1996.
2. Plant Populations
Measurements of plants per unit area were used to quantify the results of the different treatments Figure 3 illustrates the observations during seeding concerning seed bed preparation. The plant population seeded with the air seeder was highest, followed by the disker and the direct seeder. Of note is the finding that the plant populations for the direct seeder and disker were very similar, even though there was exposed seed in the direct seeding operation.
Measurements of plant height resulted in similar results to plant population (Table 1).
3. Yield
Seed yield results confirmed the fact that the lack of rainfall during the growing season was a major limitation on crop production (Table 2A). Crop yields from the various treatments were based on a harvest sample of 16 m2. Within crop variability was high, which necessitated a comparison between the 'best' parts of the block, rather than random samples. Average yield for the wheat blocks was 19.6 bu/acre. The average yield of the 'best' portions of each block was 24.8 bu/acre. A similar comparison method was used for the flax blocks, with the result that the average yield was 6.9 bu/acre, and the average of the 'best' portions was 7.6 bu/acre.
The yield results for HRSW indicated differences among seeders, as well as small differences between fall tillage treatments. The plant population differences appeared to be reflected in the final yields, with the air seeder having the highest yield of the seeders. There was little difference between yields from the disker and direct seeded crops. Yield differences due to harrowing after direct seeding were slight.
Flax yields also showed differences between seeders. The air seeder had the highest yield, followed by the disker and the direct seeder. There appeared to be approximately I bu/acre difference between the disker and the direct seeder.
Fall tillage treatments had only a slight effect on final yields. Some general trends, however, were observed. The conventional and minimum tillage treatments had a slight yield advantage over both the burn and work and the zero till treatments. Of interest is the difference between minimum and zero till treatments. The only difference between the minimum and zero till is the fact that the minimum till had a fall banding of fertilizer with knives 12" apart. It would appear to be advantageous for producers in the Red River valley if fall tillage could be reduced to a single banding operation with Knives, providing fertilizer for the next year and leaving sufficient residue to prevent soil erosion. The fall banding operation merits further study.
4. Crop Rotation
Rotations did not appear to play a major role in crop yield results at the CTPC. The wheat on wheat rotation yielded slightly higher than the wheat on flax rotation. The higher residue levels for the wheat on wheat may have helped retain some of the soil moisture, which may have enhanced the yield. Only low levels of leaf diseases were evident in the wheat.
SUMMARY
Progress was made in 1995 in assessing residue management systems on clay soils. The drought conditions made it difficult to detect any effects on yield of crop rotations and tillage regimes. The air seeder appeared to perform bettor than the direct seeder and the disker in I 995.
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Wheat Flax
Flax Wheat
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Table 2. Crop yields for wheat on wheat stubble at the CTPC, 1995
| Seeder | Burn | Convention | Minimum | Zero Till | Average |
| Concord | 22.7 | 22.3 | 24.0 | 23.8 | 23.2 |
| Concord/H | 22.6 | 23.2 | 27.3 | 25.0 | 24.5 |
| Air Seeder | 31.6 | 32.9 | 34.0 | 29.2 | 31.9 |
| Disker | 19.6 | 20.2 | 29.0 | 20.3 | 22.3 |
| Average | 24.1 | 24.6 | 28.6 | 24.6 | 25.5 |
Table 3. Crop yields for wheat on flax stubble at the CTPC, 1995
| Seeder | Burn | Convention | Minimum | Zero Till | Average |
| Concord | 22.6 | 25.8 | 21.7 | 19.8 | 22.5 |
| Concord/H | 20.4 | 27.2 | 23.8 | 19.1 | 22.6 |
| Air Seeder | 28.4 | 26.6 | 26.2 | 26.8 | 27.0 |
| Disker | 25.2 | 26.7 | 22.0 | 22.4 | 24.1 |
| Average | 24.2 | 26.6 | 23.4 | 22.0 | 24.0 |
Table 4. Crop yields for flax on wheat stubble at the CTPC, 1995
| Seeder | Burn | Convention | Minimum | Zero Till | Average |
| Concord | 6.8 | 6.6 | 6.6 | 6.0 | 6.5 |
| Concord/H | 6.8 | 6.8 | 5.9 | 6.6 | 6.5 |
| Air Seeder | 10.0 | 8.7 | 10.9 | 9.0 | 9.6 |
| Disker | 6.8 | 7.8 | 9.0 | 7.0 | 7.6 |
| Average | 7.6 | 7.5 | 8.1 | 7.2 | 7.6 |
