Liming is a relevant issue for many regions of Ukraine where soil acidity is a significant constraint. It is well established that each tonne of lime applied to acidic soils can, over the course of its effective period, generate approximately one additional tonne of grain-equivalent yield. At the same time, the traditional approach to liming — applying a uniform rate across an entire field — can be quite costly. That is why progressive farms are increasingly turning to a more modern approach to soil acidity management: variable-rate liming.
One such farm is Inter, located in the city of Ichniа, Chernihiv Region. The farm manages approximately 30,000 hectares, a significant proportion of which is affected by soil acidity. Last year, the farm decided to introduce variable-rate lime application. Vladyslav Tiutiunnyk, Deputy Director of Production, shared his insights with us on the benefits and practical considerations of this approach.
Interview with Agronomist magazine featuring Vladyslav Tiutiunnyk
Agronomist: Vladyslav Anatoliiovych, could you tell us which crops your farm specializes in?
V. T.: Corn occupies the largest share of our cropland — 22,000 hectares, or around 70%. Another 13% is allocated to sunflower. These are the key crops for the farm in terms of profitability. Winter rye and wheat each account for 6% of the cultivated area. Last year, we also planted 1,300 hectares of winter rapeseed. The remaining area is used for forage crops, as we also operate a livestock enterprise.
A.: So you grow corn as a monoculture. How many years can corn be grown on the same field?
V. T.: No more than 3–5 years. After that, we обязательно introduce another crop — wheat or sunflower. There are farms that grow corn continuously for up to 10 years. Numerous studies confirm that under continuous corn cultivation, yields do not necessarily decline over time. However, you need to take into account soil quality, moisture availability, and the accumulation of soil-borne pathogens.
A.: Your farm allocates the same area to rye and wheat. Under your conditions, are these crops equally profitable?
V. T.: Rye is a niche crop, and its price is highly volatile. In one year, a tonne may cost UAH 4,000, while in another — as was the case the year before last — it can reach UAH 8,000. So it is difficult to predict its profitability.
The area devoted to rye is largely a necessity dictated by the characteristics of our soils. They are highly variable, including sod-podzolic, dark gray, podzolized chernozem, typical chernozem, meadow chernozem, and meadow soils, with pH levels ranging from 4.5 to 8.5. We also have acidic fields dominated by sandy loam and light sandy loam soils with a light texture, where virtually nothing grows. Achieving high wheat yields there is simply impossible, while corn yields only 3.0–3.5 tonnes per hectare.
Rye has an advantage in this respect because it is less demanding when it comes to soil conditions. That is why we allocate significant areas to it. In this way, we try to increase the profitability of these less productive soils.
Rapeseed can be considered as an alternative on such soils, but weather conditions are an important factor. As every agronomist knows, without sufficient moisture, rapeseed will not perform.
A.: The area under rapeseed is relatively small compared with your other crops.
V. T.: We did not grow it at all in the past. We decided to see how it would perform under our conditions, as this region is quite risky for rapeseed production. There are two particularly critical periods for this crop: establishment and overwintering. In this region, rapeseed suffers winterkill in four to five years out of ten, meaning the risk of losing the crop can be as high as 50%. This can happen in spring, when temperatures fluctuate significantly between above and below freezing.
Last year, we sowed it very early, at the end of July, to take advantage of available moisture. We had already achieved emergence by the third or fourth day. Overall, the crop entered winter in good condition. However, because the autumn was warm, some fields required growth regulator applications as many as five times.
A.: Why did you decide to introduce this crop into the rotation?
V. T.: Rapeseed is a high-margin crop. In any given year, its price will be at least $300–350 per tonne. This year, we planted less due to weather conditions. So I think the price will hold up. Even if we achieve a yield of 2 tonnes per hectare, the crop will already be profitable.
Agronomist: What are the average corn and sunflower yields across the farm?
V. T.: Last year, our average corn yield was 8 t/ha. Depending on the field, yields ranged from 4.7 to 12 t/ha.
For sunflower, the average was 3 t/ha. Here, too, there was considerable variation — from 2 to 3.5 t/ha, as we also grow sunflower on sandy soils.
A.: What tillage system do you use?
V. T.: We have not abandoned conventional tillage. It provides us with higher yields and better profitability. On most of our acreage, we use ploughing or deep loosening combined with disc harrowing.
This year, we purchased four new Lemken ploughs, and I have to say I am very satisfied with them. I have probably never seen a better plough. How does the selection process usually work? Every company says its ploughs are the best. They gather farmers and demonstrate their performance after cereal crops. And yes, all of them work well after wheat. But when you need to plough after corn, especially when there has been lodging — as happened this year in some areas, where a storm simply flattened the plants — no one performed that job better than Lemken. It is not cheap, but at the same time, we do not need to disc ahead of it. It incorporates all crop residues perfectly.
On our sandy soils, we try to use deep loosening combined with discing. However, sometimes we also plough these areas, for example, when we need to sow winter crops in fields where Euro-Lightning was previously used, in order to accelerate the breakdown of herbicide residues. It may not be the ideal approach, but in exceptional cases we resort to this practice.
Where ploughing can be avoided, or where we need to eliminate soil compaction, we also use deep loosening.
A.: Given such significant variability in soil conditions, what yield level do you base your production technology on?
V. T.: Based on my own experience, I can say that the approach to selecting production technologies is similar across all the large agricultural holdings where I have worked — UkrLandFarming, Mriya, and MHP. Depending on soil and climatic conditions, the acreage is divided into several zones, and the technology applied in each zone is determined by its productivity: minimum, medium, or intensive.
For example, on sandy soils where the target corn yield may be 5–6 t/ha, we use lower-cost hybrids, a less expensive crop protection program, a basic fertilization program, and reduce the number of field operations. In other words, on low-productivity areas, we try to keep costs to a minimum. Where we see high potential and expect maximum yields, we increase investment accordingly.
However, at INTER, we decided not to stop there and took this approach considerably further. In 2019, our owners, recognizing the importance of changing our approach to farm management in order to maintain profitability, took a costly step: we conducted soil analyses across the entire land bank within a single year.
A.: Who did you work with on this project?
V. T.: Soil sampling was carried out by AgriLab. The samples were sent for analysis to Ward Laboratories (USA), which is considered one of the world’s leading and most respected agricultural laboratories. Based on the results, AgriLab provided corresponding recommendations. We then developed our approach to optimizing production technology based on effective yield potential, which, for corn, for example, ranged from 6 to 12 t/ha of dry grain depending on the field.
A.: What exactly did the optimization involve?
V. T.: We adjusted our hybrid portfolio and switched to banded application of phosphorus and potassium fertilizers in the fall at a depth of 18–25 cm, as a more effective and economically efficient practice. From then on, we applied only nitrogen fertilizer by broadcasting. We also began applying all fertilizers at variable rates according to the requirements of each individual field zone. In other words, we optimized our fertilizer costs.
All of our machinery is, of course, equipped with GPS navigation, from tractors and sprayers to combines.
A.: How long have you been carrying out soil acidity correction?
V. T.: We started applying lime to our fields last year, also using a variable-rate approach. Overall, we covered 4,500 hectares with the liming program, of which lime was actually applied to 2,056 hectares.
A.: Why did you decide to use variable-rate liming?
V. T.: Fields with variable soil acidity are one of the most common reasons for the presence of “productive” and “unproductive” zones on farms in the Polissia region, including ours. When soil pH varies significantly, nutrients that are present in sufficient quantities in some areas can become “locked up” and unavailable to plants. In other words, you purchase fertilizer, apply it, and get no response.
Variable-rate lime application map
Different soil pH levels lead to different fertilizer efficiencies. Moreover, some fertilizers that are suitable for use in one part of a field can further increase soil acidity in another.
When soil pH varies significantly, plant development will also differ, making such a field more difficult to manage. In addition, crops such as sunflower and corn are calcium-loving crops and perform poorly on acidic soils.
According to the soil analysis conducted by AgriLab, we found that not the entire field area required liming. Moreover, application rates in the areas requiring lime ranged from 150 kg/ha to 4 t/ha. This allowed us to save on liming wherever possible. At the same time, implementing this practice required appropriate equipment. Therefore, the company purchased a Sulky spreader capable of variable-rate application of mineral fertilizers at high application rates.
Different soil pH levels lead to different fertilizer efficiencies
The cost of lime fertilizers on the Ukrainian market is quite significant — UAH 350–550 per tonne. Transportation and the distance from the farm’s fields also account for a substantial share of the total application cost. One of the largest limestone quarries in Eastern Europe is located in Chernihiv Region. In our case, the transportation distance ranged from around 200 km. As a result, delivering one tonne of lime to the farm cost more than the lime itself, reaching approximately UAH 500, plus loading, application, and other expenses.
As a result of this approach, the cost of lime application ranged from UAH 2,500 to 3,000 per hectare (approximately $100/ha), based on an average application rate of 2.5 t/ha. Across 2,000 hectares, this amounted to UAH 6 million.
If we had applied a uniform rate across all fields instead of using variable-rate application, the cost would have been twice as high — UAH 6,000 per hectare ($200/ha). In other words, costs increase substantially under a uniform-rate approach. Moreover, applying the same rate across a field with variable soil acidity would result in over-liming some areas and under-liming others, which in turn would negatively affect fertilizer efficiency, plant development, and overall economic performance.
Variable-rate liming helps even out soil acidity variability and significantly reduce lime costs.
A.: What pH level did you aim to achieve when calculating the lime application rate?
V. T.: At least 6.0–6.5. This is the optimal range for most of our crops.
A.: What time frame did you use when determining the application rate?
V. T.: We base it on our operational capabilities. The liming window is limited by seasonality — usually from July through October, meaning we have three months during which lime can be applied. If we covered around 4,500 hectares this year, of which approximately 2,000 hectares required liming, then, theoretically, we can cover the entire land bank within five to six years.
If we take into account that soil acidity is a dynamic property and that shifting the pH toward neutral is a temporary process, the soil will gradually return to its original, genetically determined level several years after liming.
I think that in four to five years we will be able to conduct another soil analysis and, based on the results, plan the next round of liming for the areas that require it.
A.: In your opinion, how economically justified is liming?
V. T.: You can hire the best consultants from abroad, and the first thing they will ask for is soil analysis results — specifically, the soil’s calcium requirement. The second thing they will check is whether the soil is compacted. These are the fundamentals on which all subsequent actions and the final field result depend.
In Ukraine, business owners generally understand and have heard that liming is an important agronomic practice. Agronomists are even more aware of this. However, because the practice is expensive, most farms do not lime their soils. And this applies not only to medium-sized farms, but also to large agricultural holdings. Everyone seems to have the intention and desire to do it, but finance departments at large holdings are usually opposed to treating the cost of applying lime fertilizers as an investment spread over two to four years. As a result, agronomists are asked to charge the entire cost of liming to the following year’s production costs for a particular crop. Given limited budgets allocated to agronomy departments, agronomists simply abandon the practice.
Managers of agricultural holding divisions may conduct trials to demonstrate to financial departments that liming can be economically beneficial. The problem is that the effect of soil acidity correction does not appear in the year of application, but only in the second or third year.
Finance departments, in turn, convince business owners that such projects are simply not worth funding. This is one of the reasons why liming remains so uncommon in Ukraine.
If we use the “old-school approach” and apply lime at a uniform rate of 4–8 t/ha rather than using variable-rate application, the cost per hectare makes it clear why few farms are willing to do it. The lack of government support programs only deepens the problem.
Another issue, in my opinion, is the way many farmers approach agronomic challenges. In some respects, we may even be more progressive than others, but we often try to reinvent the wheel where there is no need to. For example, if an American farmer receives soil analysis results indicating that liming should be the first priority and specifying the required rate, they simply lime the field. Here, we start experimenting, looking for “magic” fertilizers as alternatives, or calculate the cost and decide: “We will do everything except liming because it is too expensive.” And then we wonder why nothing grows there.
Published in Agronomist magazine, 2021
According to the soil analysis conducted by AgriLab, we found that not the entire field area required liming. Moreover, application rates on the field areas requiring lime ranged from 150 kg/ha to 4 t/ha. This allowed us to reduce liming costs wherever possible.
