Sunflower Variable-Rate Seeding: Experiment
on 50 Fields
Reading time — 5 minutes
Short notes
I have been experimenting with variable-rate sunflower seeding since 2017. I've already talked about some of my field tests in the blog. Most often, my experiments ended up as follows: a decrease or increase in the seeding rate were compensated by the size of the sunflower head. But I had to conduct experiments on a large number of fields to come to an accurate conclusion.
In order to make precise recommendations for variable-rate sunflower seeding, I decided to conduct a large-scale experiment. In 2020, I set up field trials on 50 fields in Russia and Ukraine. The fields were different in area and were located in different soil and climatic conditions. Five agricultural holdings and eleven farms participated in the experiment. In this article, I'll tell you about my conclusions and answer the main question: does it make sense to do variable-rate seeding with sunflowers?
In order to make precise recommendations for variable-rate sunflower seeding, I decided to conduct a large-scale experiment. In 2020, I set up field trials on 50 fields in Russia and Ukraine. The fields were different in area and were located in different soil and climatic conditions. Five agricultural holdings and eleven farms participated in the experiment. In this article, I'll tell you about my conclusions and answer the main question: does it make sense to do variable-rate seeding with sunflowers?
Usevalad Henin
Usevalad is an expert in GIS and agricultural chemistry. He has been developing precision farming tools since 2013. He is also the co-founder of OneSoil.
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Usevalad Henin
Usevalad is an expert in GIS and agricultural chemistry. He has been developing precision farming tools since 2013. He is also the co-founder of OneSoil.
I have been experimenting with variable-rate sunflower seeding since 2017. I've already talked about some of my field tests in the blog. Most often, my experiments ended up as follows: a decrease or increase in the seeding rate were compensated by the size of the sunflower head. But I had to conduct experiments on a large number of fields to come to an accurate conclusion.
In order to make precise recommendations for variable-rate sunflower seeding, I decided to conduct a large-scale experiment. In 2020, I set up field trials on 50 fields in Russia and Ukraine. The fields were different in area and were located in different soil and climatic conditions. Five agricultural holdings and eleven farms participated in the experiment. In this article, I'll tell you about my conclusions and answer the main question: does it make sense to do variable-rate seeding with sunflowers?
In order to make precise recommendations for variable-rate sunflower seeding, I decided to conduct a large-scale experiment. In 2020, I set up field trials on 50 fields in Russia and Ukraine. The fields were different in area and were located in different soil and climatic conditions. Five agricultural holdings and eleven farms participated in the experiment. In this article, I'll tell you about my conclusions and answer the main question: does it make sense to do variable-rate seeding with sunflowers?
Here're the locations where my seeding prescriptions were used
Experimental setup
Experiments on all 50 fields were conducted under the same scheme.
Yield productivity zones
For the experiment, I selected fields with different soils: chernozem, grey forest, chestnut, and sod-podzolic soils. In low-productivity areas, the yield was most often limited by moisture redistribution and soil erosion. It turned out that relief was the limiting factor in most of the fields. Fields with low acidity and salinity also occurred, but rarely.
I also experimented on fields where irrigation was used.
I also experimented on fields where irrigation was used.
Sunflower seeding rate
In all the experimental fields, I tried to set three seeding rates for each productivity zone. Seed rate of sunflower per hectare varied from field to field. On some farms, I tested a wide range of 40 to 70 thousand seeds. On others, I used 56 to 62 thousand seeds.
You can create prescription maps for any crop in the OneSoil web app
Sunflower seed germination
After planting, together with the agronomists of the farms that participated in the experiment, we monitored plants' development, evaluated the germination rate, measured the heads' diameter, moisture, and grain weight. At that step, I had already made several conclusions.
The sunflower germination rate decreases as the seeding rate increases.
The difference in germination between seeding rates of 40 and 65 thousand seeds was about 8% on average. I couldn't fully understand why this happened. It's unlikely that the soil type, climate conditions or the hybrid choice were the reason. This question should be investigated deeper.
Variability of head diameter in sunflower
The head diameter depends on the seeding rate. As the seeding rate increases, the head diameter decreases. The opposite is true for decreasing the seeding rate.
I noticed this pattern for both high and low productivity zones. The soil type also had no effect on this pattern: both on sod-podzolic soils and on chernozem, the relationship between the seeding rate and head size remained the same.
During ripening, grain moisture is higher in zones with low seeding rates than in zones with high seeding rates.
I noticed this pattern in all productivity zones. The difference, if it was visible, was 0.5-1%.
Conclusions and recommendations
Let me remind you that seeding rates in the experiment were different for all fields: from 40 to 62 thousand seeds. All the fields were harvested by combines with yield monitoring systems, and yield maps were quite accurate.
Nevertheless, on none of the fields I recorded the impact of seeding rates on the sunflower yield.
Sunflowers are not sensitive to seeding rate. Therefore, I would recommend reducing the seeding rate for sunflower. The money you save can be spent to buy a better sunflower hybrid. With the same expenses, the yield will be higher.
Nevertheless, on none of the fields I recorded the impact of seeding rates on the sunflower yield.
Sunflowers are not sensitive to seeding rate. Therefore, I would recommend reducing the seeding rate for sunflower. The money you save can be spent to buy a better sunflower hybrid. With the same expenses, the yield will be higher.
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