"90% of Farmers Know Nothing About Soil Analysis"
Reading time–10 minutes
We talked to Valeria Vashchenko, CTO at Zemlerob, about why grid sampling for soil analysis is a thing of the past and how to take soil samples properly with OneSoil.
Zemlerob provides soil sampling and soil analysis services in Ukraine. It also develops plant nutrition systems and researches soil mapping techniques. By now, the company has more than 300 clients across the country. Their employees travel about 4,000 kilometers a day. They often say that the most important thing in their work is to study each field carefully and not to promise quick results.
In this interview, we'll discuss what factors are important to consider when doing soil analysis and why traditional soil mapping techniques are hopelessly outdated.
In this interview, we'll discuss what factors are important to consider when doing soil analysis and why traditional soil mapping techniques are hopelessly outdated.
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Zemlerob provides soil sampling and soil analysis services in Ukraine. It also develops plant nutrition systems and researches soil mapping techniques. By now, the company has more than 300 clients across the country. Their employees travel about 4,000 kilometers a day. They often say that the most important thing in their work is to study each field carefully and not to promise quick results.
In this interview, we'll discuss what factors are important to consider when doing soil analysis and why traditional soil mapping techniques are hopelessly outdated.
In this interview, we'll discuss what factors are important to consider when doing soil analysis and why traditional soil mapping techniques are hopelessly outdated.
Calculate fertilizer and seeding rates
For variable-rate application. Detect productivity zones and create prescription maps for equipment in the OneSoil web app.
Calculate fertilizer and seeding rates
For variable-rate application. Detect productivity zones and create prescription maps for equipment in the OneSoil web app.
Why traditional soil analysis methods no longer work
— Valeria, tell us about your company's approach to soil analysis.
In Ukraine, soil samples are still mostly taken by a hectare grid. The truth is, there are more than 20 soil types in the country. On some farms, there may be more than five soil types even within one field. So if we want to develop effective plant nutrition systems, we should approach soil sampling and research methods more precisely. Innovations in soil analysis and nutrient systems are exactly what our company does. We study different soil mapping techniques and test them in the field.
In Ukraine, soil samples are still mostly taken by a hectare grid. The truth is, there are more than 20 soil types in the country. On some farms, there may be more than five soil types even within one field. So if we want to develop effective plant nutrition systems, we should approach soil sampling and research methods more precisely. Innovations in soil analysis and nutrient systems are exactly what our company does. We study different soil mapping techniques and test them in the field.
Almost every day, Zemlerob agricultural chemistry specialists visit farmers, study their fields and take soil samples
On the one hand it's simple, but on the other hand there are some peculiarities you should know about. All the data and tools we use now were invented decades ago. But the problem is putting this data together and analyzing it. For example, we have data on yield, topography, soil brightness, vegetation index, agronomist observations, and soil conductivity scans. Ideally, all of this data should be interconnected. If we see a lower NDVI index in one area, we'll also see a lower organic matter content and lower yield in this part of the field. In 40% of cases, this kind of relationship is easy to see. But when we compare this data and don't see any connection, we need to look for other factors that might have affected the yield.
Another problem is that very often farmers simply don't have all this data.
Another problem is that very often farmers simply don't have all this data.
Many of them don't even have electronic field maps — we use them to map potential sampling areas
This is Boss. He's in charge of the company. He knows how to do soil mapping and can tell the difference between sand and chernozem
Finally, 90% of farmers know nothing about soil analysis. Soil testing is usually done the same way as decades ago: people from state scientific institutes come to farmers, walk chaotically across the field with shovels and take soil samples (a note from OneSoil: until recently, only state scientific institutes did soil testing in the CIS). So what does the farmer get? A map where one sample is interpolated over the entire field. And most farmers are okay with this. When we work with these farmers, we always start with the basics: we explain why we can't analyze phosphorus content by using just one method, why it's important to understand the difference between soil types, and what happens if sandy soil is mixed with sod-podzolic soil. Basically, we tell farmers everything about the process of soil analysis.
— Let's say we want to order a soil survey from you. What happens after the application?
If a farmer plans to do a soil analysis, it's a sign for us that they want to use fertilizers more efficiently. As soon as we receive an application, agricultural chemistry specialists visit the farmer. On the spot, we find out if the farmer is using yield sensors and any tools for monitoring vegetation indices. As I said, most of the time we don't have this kind of data.
If a farmer plans to do a soil analysis, it's a sign for us that they want to use fertilizers more efficiently. As soon as we receive an application, agricultural chemistry specialists visit the farmer. On the spot, we find out if the farmer is using yield sensors and any tools for monitoring vegetation indices. As I said, most of the time we don't have this kind of data.
So the first thing we do upon arrival is registering the farmer in the OneSoil web app. This makes it easier to immediately navigate through all the fields.
We look at the fields' NDVI in the OneSoil web app and ask the agronomist why certain plots have a lower index. For just one hour, we're checking about 500 hectares of fields. If we see any critical issues on the map, we go to the field. Actually, this happens in 80% of cases. When we're in the field, we check whether the agronomist's comments correspond to reality. We also take soil and leaf samples or make a soil cut. Then we send the samples to the laboratory.
Zemlerob employee at work. He's telling farmers about the soil test results for their farm
Let's say we analyzed all the data and gave you the soil test results. I can tell you right away that almost none of the farmers understand these figures.
Is 111 million-1* of potassium good or bad?
This is why we have developed a special report where each value has a letter indicating the nutrient's content in the soil. Also, the report is divided into two parts: the first part contains data on soil health indicators, the second one provides data on nutrient content. We evaluate soil health by looking at its texture, acidity, buffer pH, soil salinity, and base saturation.
When we see the content of all these elements in one table, we can determine the limiting factor in the field. For example, extremely acidic soil or high calcium content can limit the phosphorus content. By understanding the relationships between the elements, we make recommendations for plant nutrition systems.
When we see the content of all these elements in one table, we can determine the limiting factor in the field. For example, extremely acidic soil or high calcium content can limit the phosphorus content. By understanding the relationships between the elements, we make recommendations for plant nutrition systems.
How OneSoil helps take soil samples and prepare for soil analysis
— When did you start using OneSoil?
About two years ago, OneSoil postcards came to our office (Note from OneSoil: in 2018, we raffled off postcards with pictures of fields from our CEO on social media). And I took an interest in the company. This is how I started using the web app. Now all our employees use it. When we hire young professionals, OneSoil is one of the applications we require them to study.
In fact, we tried a lot of scouting apps. OneSoil turned out to be one of the most convenient. First, the app has a cool interface and website, and a friendly support team. Second, the app is free. Third, there is a map with marked field boundaries.
About two years ago, OneSoil postcards came to our office (Note from OneSoil: in 2018, we raffled off postcards with pictures of fields from our CEO on social media). And I took an interest in the company. This is how I started using the web app. Now all our employees use it. When we hire young professionals, OneSoil is one of the applications we require them to study.
In fact, we tried a lot of scouting apps. OneSoil turned out to be one of the most convenient. First, the app has a cool interface and website, and a friendly support team. Second, the app is free. Third, there is a map with marked field boundaries.
With OneSoil, we don't have to waste time looking for electronic field maps or marking boundaries manually. You can get to work right away.
But the coolest thing that OneSoil has come up with, in my opinion, are productivity zones. After reading your blog article about productivity zones, we've been using them every day. We check productivity maps in the web app and compare them to the current situation in the fields. They match in 70% of cases. Also, you can quickly export fertilizer prescription maps from the web app and use them in other programs.
With all these features, we've reduced field data processing by 50%.
With all these features, we've reduced field data processing by 50%.
Productivity zones in the OneSoil web app
— Valeria, why do you use productivity and NDVI zones in your work?
We use productivity zones to decide where to take samples. We put geotags in certain points in the web app, and then send the agronomists to these areas. They examine the selected areas and check if there is soil heterogeneity.
We use productivity zones to decide where to take samples. We put geotags in certain points in the web app, and then send the agronomists to these areas. They examine the selected areas and check if there is soil heterogeneity.
Vegetation index zones help us make an initial assessment of the fields.
High and low NDVI zones, no matter what they are associated with, tell us where to look for the cause of heterogeneity in the field. On the other hand, when we apply some fertilization strategy, vegetation index zones help us analyze test plots where we're trying different fertilizer rates or testing new products. Satellites are always a good way to see how one product or another is working. One area of the field might be greener, for example. It means it has a higher vegetation index and the product we tested there performs better.
NDVI map in the OneSoil web app
How to take soil samples properly
— If I asked you about how to take soil samples properly, what would you advise?
First of all, I would ask you why you're doing soil analysis, how you want to use it, and what equipment you have for it. It all boils down to the type of fertilizer application. If you're using a spreader, it changes the rate by 10 kilograms about every 10 meters (depending on the brand). If you don't have a spreader and you don't plan to switch to variable-rate application, we can analyze the NDVI map, study the productivity zones, and select plots for taking soil samples based on this data. It is better to select plots that don't exceed 20 hectares.
First of all, I would ask you why you're doing soil analysis, how you want to use it, and what equipment you have for it. It all boils down to the type of fertilizer application. If you're using a spreader, it changes the rate by 10 kilograms about every 10 meters (depending on the brand). If you don't have a spreader and you don't plan to switch to variable-rate application, we can analyze the NDVI map, study the productivity zones, and select plots for taking soil samples based on this data. It is better to select plots that don't exceed 20 hectares.
— How do we approach soil sampling if we are planning variable-rate application?
If we are aiming for precision farming, I would advise to start by studying all the available data, preferably for the last three years: from topography to yield maps. Then move on to soil sampling: select zones and divide them by grid. The grid density depends on your budget and the crop you're growing. If it's a highly profitable crop that responds well to small rate changes, you can use a one-hectare grid. But if we're dealing with wheat, a 5-hectare grid would be enough according to our experience. Remember that we use the grid in just one zone, and there will be several zones in the field.
Also, it often happens that in the middle of the field we have 10 hectares of sand dunes. I would not advise taking soil samples in this area. There are many factors that limit the yield there. Your effort and time on these areas won't pay off.
If we are aiming for precision farming, I would advise to start by studying all the available data, preferably for the last three years: from topography to yield maps. Then move on to soil sampling: select zones and divide them by grid. The grid density depends on your budget and the crop you're growing. If it's a highly profitable crop that responds well to small rate changes, you can use a one-hectare grid. But if we're dealing with wheat, a 5-hectare grid would be enough according to our experience. Remember that we use the grid in just one zone, and there will be several zones in the field.
Also, it often happens that in the middle of the field we have 10 hectares of sand dunes. I would not advise taking soil samples in this area. There are many factors that limit the yield there. Your effort and time on these areas won't pay off.
Interview conducted by Tanya Kovalchuk
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