Can sugar beet yield be influenced by planter down force, planting depth or planted population?

Results from the Crop Tour sugar beet plot 2018 on Swiss Future Farm in Tänikon.

Precision Planting - Feature
March 25, 2019 by AGCO

Can sugar beet yield be influenced by planter down force, planting depth or planted population?

Results from the Crop Tour sugar beet plot 2018 on Swiss Future Farm in Tänikon.

During the season of 2018 on AGCO’s Swiss Future Farm, we have been investigating how planter row unit down force and its variation during planting can effect yield in sugar beets. Additionally, we have analyzed the yield response of different planting depths and planted populations.
For this Crop Tour sugar beet trial plot, we have been using a Precision Planting test planter with 3 meters working width, 6 rows and 50 cm row spacing that was equipped with DeltaForce, SpeedTube and SmartFirmers by Precision Planting (Figure 1). This planter is using a load pin that enables down force adjustment according to the current soil conditions during planting to ensure consistent planting depth throughout each planter pass. On heavy or compacted soil, down force is increased automatically via the Precision Planting DeltaForce system, whereas it is reduced as soon as the planter is working in lighter soil. In this way, consistent planting depth and even emergence is ensured, while eliminating the risk of a compacted seed furrow.
Figure 1 - Precision Planting

Figure 1 – Precision Planting test planter during sugar beet planting at Swiss Future Farm on 12th April 2018.

On Swiss Future Farm, we were aiming to prove these considerations under commercial farming conditions and set up a strip trial (Figure 2) to demonstrate the effect of these different planter settings on sugar beet yield.
Figure 2 - Precision Planting

Figure 2. AGCO Crop Tour sugar beet trial plot 2018 on Swiss Future Farm – 1: Auto Down Force, 2: Heavy Downforce, 3: Light Down Force, 4: Planting Depth 1 cm, 5: Planting Depth 4 cm, 6: Planting Depth 6.5 cm, 7: Population 150’000 plants/ha.

Even field emergence with higher down force

Crop care was done uniformly for all 7 trial strips. Total fertilizer rates were 86.4 kg N/ha. The planted population was 100’000 plants/ha for 6 trials strips, and in an experimental approach we increased the planted population to 150’000 plants/ha. The trial site is characterized by heavy soils with high clay contents. In the dry year of 2018, precipitation was comparably low with 800 mm/year, compared to the long-time average of 1200 mm/year.
Figure 3 shows the trial strip that was planted with a standard planting depth of 2.5 cm. In this strip, down force was continuously measured and automatically adjusted using the DeltaForce system to ensure consistent planting depth for the entire planter pass. It is clearly evident, that beets emerged very homogenously here (Emergence Score: 80.5% measured with Precision Planting PogoStick).
Figure 3 - Precision Planting

Figure 3. Trial strip 1: Automatic down force at 2.5 cm planting depth.

In Figure 4, the trial strip planted with 2.5 cm planting depth but with heavy downforce is shown. Here, down force was set to the maximum value of constantly 27.5 bar. This trial strip also showed very homogenous field emergence (Emergence Score 88.5% measured with Precision Planting PogoStick).
Figure 4 - Precision Planting

Figure 4. Trial strip 2: Maximum down force (27.5 bar) at 2.5 cm planting depth.

Figure 5 shows the third trial strip, which was planted with minimum downforce of constantly 0 bar at 2.5 cm planting depth. Beets on this trial strip showed very delayed and sparse emergence (Emergence Score 2.3% measured with Precision Planting PogoStick). As a consequence, this trial strip had to be replanted at a later point in time.
Figure 5 - Precision Planting

Figure 5. Trial strip 3: sparse emergence of beets with minimum down force at 2.5 cm planting depth.

Effect of down force on yield

Yield measurements of the sugar beet trial plot were done individually for each trial plot. Each strip was harvested with a 6-row sugar beet harvester, loaded to a trailer and weighed on a scale. Soiling of the beets was low in general, nonetheless 7% soil residue content was deducted from the measured yield.
Diagram 1 shows, that highest yield was measured in the trial strip that was planted with maximum down force of 27.5 kPa. Interestingly, no remarkable differences were found yet during field emergence in comparison to automatic down force. The exceptionally low precipitation in Spring 2018 and a comparably cloddy seedbed favored this setting. Consequently, the trial strip with maximum down force showed higher yield in comparison to the trial strip with automatic down force setting that was adjusted according to sensor measurements.  This result must be interpreted with caution, as too much down force under normal seedbed conditions will cause compaction in the seed furrow and severely affect root development, resulting in significant yield decrease. Therefore, we will repeatedly evaluate this comparison of down force settings in upcoming crop cycles.
Diagram 1 - Precision Planting

Diagram 1. Fresh mass yield (tons/ha) for the sugar beet trial strips on Swiss Future Farm.

Due to total crop failure, there were no yield measurements possible for the trial strips that were planted with minimum down force at 0 bar and with a planting depth of 1 cm. After only sparse emergence, these trial strips were replanted later in the season and yield results are not comparable to the original trial strips.
In the very dry year of 2018, deeper planting depths proved to be advantageous in sugar beets. When comparing the trial strips planted with automatic down force, both 4 cm and 6.5. cm planting depth showed higher yields than the normal planting depth of 2.5 cm.
Figure 6 shows hand-harvested beets from the three trials strips with increased planted population of 150’000 plants per hectare, DeltaForce automatic down force control, and excessive down force, respectively.
Figure 6 - Precision Planting

Figure 6. Hand-harvested sugar beets from the three different trials strips on Swiss Future Farm.

Analysis of sugar content

For analysis of sugar content, 20 beets were collected per trial strip. Results for sugar content of beets from the different trial strips are shown in Diagram 2. Highest sugar content was found in beets planted at 4 cm planting depth, whereas lowest sugar content was found in beets sampled from the trial strip with a planted population of 150’000 plants per hectare.
Diagram 2 - Precision Planting

Diagram 2. Sugar content (%) for the sugar beet trial strips on Swiss Future Farm.

Revealing the final results – sugar yield

Final assessment of the ROI in sugar beets has been made for sugar yield as a result of fresh mass yield and sugar content. Diagram 3 shows a comparison of sugar yield in tons per hectare for the different trial strips.
Diagram 3 - Precision Planting

Diagram 3. Sugar yield (tons/ha) for the sugar beet trial strips on Swiss Future Farm.

Down Force Study: Highest sugar yield under the trial conditions in 2018 was obtained from beets planted with heavy down force at 2.5 cm planting depth (Diagram 4). As already mentioned above, this result must be interpreted with caution, as too much down force under normal conditions will cause compaction in the seed furrow and severely affect root development. In this individual case with a cloddy seedbed for planting in the season of 2018, heavy downforce may have enabled closer soil contact of the seed, higher capillary action in the soil and therefore more uniform moisture in the furrow to enable beet emergence.  However, in well prepared seedbeds, the higher downforce may have adverse effects.
Diagram 4 - Precision Planting

Diagram 4. Down Force Study – sugar yield in tons/ha. Sugar yield was higher for the Heavy Down Force trial strip, but has to be interpreted with caution, as these results were generated in a cloddy seedbed. Heavy or maximum down force will have adverse effects in a find, crumby seedbed.

Planting Depth Study: Regarding different planting depths, the results shown in Diagram 5 demonstrate that in that dry year of 2018 beets planted at 6.5 cm planting depth were placed closer to the moisture horizon and could accumulate more sugar than beets planted at usual planting depth for sugar beets of 2.5 cm. The ascending yield level at deeper planting depth shows that the moisture horizon was located deeper under this year’s conditions.
Diagram 5 - Precision Planting

Diagram 5. Planting Depth Study – sugar yield in tons/ha. Sugar yield increased with deeper planting depth that was closer to the moisture horizon.

Population Study: Our results show that a higher planted population of 100’000 vs. 150’000 plants per hectare increased sugar yield by 2.3 tons (sugar yield 19.1 vs 16 tons/ha). In our case, this increased the revenue from CHF 6722 to CHF 7171 per hectare (+ CHF 449). The higher planted population of 150’000 plants/ha resulted in additional seed costs of CHF 152 (CHF 333 vs. CHF 485 for the different populations). This analysis demonstrates an advantage of CHF 297 per hectare for a higher planted population of 150’000 beets per hectare.
Diagram 6 - Precision Planting

Diagram 6. Population Study – sugar yield in tons/ha. Sugar yield increased by 2.3 tons comparing planted populations of 100’000 vs. 150’000 per hectare.

Outlook and next steps

During the season of 2019, Swiss Future Farm will continue to investigate the effect of different down force and planting depth settings in sugar beets and corn. Therefore, the trials will be repeated on a different site, in order to gain confidence in the results. As a novel approach, we will investigate how liquid fertilizer application can strengthen sugar beet development in the juvenile stage.

Contact Information:

Nils Zehner, Agricultural Engineer, AGCO Corporation & Swiss Future Farm, nils.zehner@agcocorp.com
On behalf of AGCO, Nils Zehner is working as Farm Manager on Swiss Future Farm, a showcase farm for Fuse Technologies located in Switzerland. Being an Agricultural Engineer, the promising features of Precision Planting technology have profoundly drawn his interest. The Crop Tour plots on Swiss Future Farm enable to explore the functionalities of Precision Planting in corn and sugar beets.

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