Which type of corn hybrid should be selected for a variable rate seeding?

Are all hybrids of maize react to the change in the rate of seeding equally well? Last year, together with Ukrainian agropromholding ASTARTA-Kyiv, we in OneSoil decided to test it in practice and conducted a field experiment.

Five hybrids were chosen for experience: КВС 4484, КВС 381, МАС 24.С, ДКС 3730, GRAND 6. As the experiment passed and what strategy of sowing turned out to be the most successful for each hybrid, I will tell in this material.

ASTARTA-Kyiv is a large agricultural holding in Ukraine. Land bank – about 230 thousand hectares. The Holding is engaged in agricultural production, sugar production, soya processing, and dairy cattle breeding.

ASTARTA-Kyiv cooperates with AgriChain Company, which develops an information portal for agribusiness management. With its help, the holding company monitors the production processes, the land bank, and the crops. Also, AgriChain constantly studies and tests technologies and equipment that can improve the efficiency of agro-companies. Proven field-proven AgriChain technologies recommend to their customers and integrate into their tools. Experiments with Astarta started with AgriChain initiative.

The first of them was held in Poltava and Vinnytsia regions. The soil in these regions is mainly as follows: Black earth is insulated, black earth is typical low-humus and gray forest.

How that experience happened.

First of all, I studied areas of productivity in holding fields in both regions. Done so in the OneSoil web application. It happened as follows: I chose an interesting field on the map, opened the tab “sowing”, and filled in the sowing. A few minutes later, the plugin analyzed the selected field and built a zone of productivity for it.

Here is how you can select areas of productivity in your field. It’s free
It was then important to assess the stability of the productivity zones in all fields. For this purpose, I compared the vegetation maps for the last 3-4 years in the key phases of plant development. Under the key phenological phases, I mean the stages when the data of vegetation and actual yield are maximally connected. If the figure from year to year roughly coincides, the zones of productivity on the field can be considered stable, if very different – no. For the experiment, I chose fields with stable zones of productivity. Why is it so, let us say a little below.

To see how the vegetation zones on the field have looked on any day in the last 3-4 years, you can see them in the OneSoil web application. Will have a little sweat, but it is worth it.
Once the fields for experience were selected, it was possible to move to the card tasks. The standards for testing were: 65 thousand, 77 thousand, and 90 thousand seeds per ha. For all fields, they were selected by agronomists “Astarta-Kyiv”. My task was to divide these norms into productive zones so that three norms of clearance were put into each zone. It is on this principle that seed maps were built.

This is a task map for the sowing of the hybrid of BC 381. I created it in the QGIS plugin
The next stage is the analysis of yield maps after harvest. For this purpose in each zone of productivity, I have allocated homogeneous zones. These are small areas, with an area of up to 0,4 hectares, with approximately the same rate of cut and yield at each point. From experience, this area includes two passes of the combine. For each homogeneous zone, I calculated the average yield value and then estimated the tendency to increase or decrease the yield.

look like this homogeneous zones in one of the fields

What was important to take into account in the field research?

Zones of productivity in the fields of experiments should be stable. If from year to year the zones of productivity are located on the field equally, therefore, field productivity does not depend on the peculiarities of culture and climatic conditions. With this approach, climatic factors will not affect the results of the experiment and you can assess the role of the hybrid in increasing or decreasing crop yield.

It is important to calibrate the combine and use the yield monitoring systems. Otherwise, it will not be possible to track the impact of the seeding rate on the planting result. Or you will get an inauthentic yield value that cannot be relied upon.

How did the hybrids react to the change in the norm?

KVS 4484. In all areas of productivity, the yield increased with a reduction in the cutting rate to 65 thousand seeds per hectare. In the future, the norm of height for this hybrid can be safely reduced.

KVS 381. In low- and medium-productivity areas, the yield also increased with a reduction in the cutting rate. In areas of high productivity – with an increase of up to 90 thousand seeds. It turns out that the strategy of sowing this hybrid will depend on the zone of productivity.

MAC 24.C. In the areas of average productivity, the rate of seeding virtually did not affect the yield. In low-productivity areas, crop yields have decreased. In areas of high productivity, the yield has increased with an increase in the rate of seeding.

COP 3730. In the areas of medium and low productivity, the yield has increased with a reduction in the cutting rate. In areas of high productivity, on the contrary: At a rate of 65 thousand seeds per hectare, the yield decreased. At the rate of 77 and 90 thousand differences in yield were not. It turns out that in the zone of high productivity this hybrid could be used medium rate.

GRAND 6. In areas of high productivity, the yield increased with an increase in the rate of seeding to 90 thousand seeds per hectare. In areas with average productivity, the average cutting rate worked best. In low-productivity areas, the rate of production did not change.

Comparative table of yield in zones of productivity

Results of the experiment and recommendations

In my experience, I confirmed that the technology of differentiated corn sowing works and can increase the profitability of production. But different hybrids in different ways react to differential sowing. I have observed this in this particular experience, as well as in other agricultural holdings of Ukraine and farms all over the world.

If you plan to bet on the increase in profitability due to differentiated maize crop, it is important to test different hybrids and choose one of them, which is on your field and in your climatic conditions will give a greater increase in yield. The results of this experiment are suitable only “Astarta-Kyiv” and only for the fields where the experiment was placed.
In its field investigations it is important to thoroughly analyze the areas of productivity on the field, test different strategies for the distribution of seeds across zones, and harvest a combine with yield monitoring.

Author: Vsevolod Genin,
Specialist in GIS and agrochemistry. Develops tools for accurate farming since 2013. Co-founder of OneSoil.
Source and photo: blog.onesoil.ai