Concept of the Soil in Balance does not make sense

The 'Soil in Balance' method is promoted with great fervor by a number of specialist laboratories and consultancy firms in the Netherlands as the best method for working on sustainable soil and agriculture. Are the underlying claims justified? No, Gerard Ros substantiates.

From the early 1900s, soil scientists and agronomists have been looking for soil analyzes that provide insight into the soil quality and the need for fertilization. The basic idea behind this is that the soil must be in order in order to feed the plant properly. There has also been a long search for an optimal ratio between the cations, in particular calcium, magnesium and potassium.

These ratios determine whether the Soil is in Balance. Today this method is also known as the Kinsey-Albrecht method. The balance method is promoted with great fervor by a number of specialist laboratories and consultancy firms in the Netherlands as the best method for working on sustainable soil and agriculture. However, are the underlying claims justified?

The underlying concept behind the balance method is at odds with the common scientific concept of 'availability', a concept that essentially builds on the insight of Justus von Liebig that the nutrient is the most restrictive in the growth of a crop. Even though von Liebig has ignored some biological aspects of the soil, the underlying idea of ​​capacity, intensity and buffering has been extensively substantiated in recent decades with long-term system trials. Is the balance method a good alternative? Let me get straight to the point: in my opinion the use of the balancing method does not fit within a sustainable use of the soil.

Reason 1. There is no relationship with crop growth
More than 100 years ago, the search for soil analysis methods to optimally fertilize crops started. In addition, optimum ratios between cations have always been sought. In 1916, Lipman concluded that based on the then known research, no relationship could be demonstrated between the ratios of cations and crop yield. In the 30s to 50s, Moser, Bear and Bear & Toth reached the same conclusion: crop growth is possible over a wide range of cation ratios. In order to counteract the luxury consumption of potassium, a high occupancy of calcium was advised.

Based on several studies in the early 20th century, an ideal range was assumed for cations in the soil. The ideal soil would contain 65 to 85% Ca, 6 to 12% Mg, and 2 to 5% Potassium. Over the years, this 'optimal' ratio has been adjusted a number of times, unfortunately without documentation of the underlying arguments. Research by Albrecht in the 30s subsequently led to an ideal soil containing 60 to 75% Ca, 10 to 20% Mg, 2 to 5% K, 10% H and 5% other cations.

Here, too, the exact rationale is unclear. Was there a relationship with crop yield or not? It doesn't seem so, because in all the research after 1950 there is no evidence that there is a relationship between the ratios of cations for both crop yield and crop quality. The general impression was that a wide bandwidth was possible, without consequences for yield or crop quality.

Using 15 field trials, Chaganti & Culman again concluded in 2013 that there is no demonstrable effect of cation ratios on crop yield. I think, based on these analyses, we can say that it is not necessary to aim for an optimal cation balance in order to grow a healthy crop.

Reason 2. There is no relationship with soil structure or soil biology
The concept of 'Soil in Balance' assumes a positive effect of cation ratios on crop growth through changes in soil structure and reduced water intrusion. However, the extensive 2007 study by Kopittke & Menzies finds no evidence for this. Rather the opposite. For Dutch clay soils, preference is given to the highest possible occupation with calcium, because potassium or magnesium strongly promote the swelling behavior of clay.

There are also no (published) indications that a 'balanced soil' influences biological activity positively or negatively. Research by Schonbeck (2000) and Kelling (1996) show this, for example, for the population of earthworms. This is also indirectly clear from all the promotional material of consultancy firms that argue in favor of the balance sheet method. The advice for stimulating soil life and the management of organic matter (and these advices are often in accordance with Good Agricultural Practice) are substantively separate from the balance method used.

Reason 3: The balance method is not sustainable
Various tests carried out in the Netherlands confirm the above conclusion. Between 2012 and 2015, trials were conducted at the experimental farms Ebelsheerd in Nieuw Beerta and 't Kompas in Valthermond. A four-year trial with wheat was carried out at the first test location, where fertilization according to the balance method resulted in a significantly higher dose of K, Mg, S, B, Cu and Zn. However, it had no effect on crop yield.

The advice to give extra trace elements is also striking, precisely because wheat is not known as a sensitive crop. Significantly higher gifts were also given at the second trial location without a significant difference in production (measured over a four-year building plan). Recent tests on experimental farms (Bussink 2020) confirm this for a potato construction plan. In practice, the extra fertilization costs exceed the additional yield, which means that on balance it is not financially viable.

In accordance with the study by Kopittke & Menzies (2007), we have to conclude that the concept of 'the Soil in Balance' does not make sense. There is no solid evidence that fertilization should be aimed at achieving optimal cation ratios in the soil. The system, on the other hand, rather leads to unnecessary use of fertilizers and thus to waste.

Edmeades (2011) and a large group of South African researchers and agronomists (Miles 2013) also draw the same conclusion. Closer to this, the same conclusion is supported by the German Department of Soil Science of the VDLUFA. Old liming tests in Germany showed that the calcium occupancy at the complex had no relationship with the grain yield. The VDLUFA therefore concluded in 2018 that the 'Soil in Balance' method is outdated, because it relies (too) strongly on an oversimplified soil science concept (Nätscher, 2018).

So why the popularity?
Nevertheless, the system of 'Soil in Balance' is popular in certain circles. Positive experiences of farmers are often used as motivation. This is of course also a fact, but it is important to continue to ask about the underlying reason. The agricultural experts in Miles (2013) indicate that 'better yields' based on experience often rely on better crop management.

Whether this is also the case in the Netherlands seems to be confirmed by a report from study groups from the Northern Netherlands. Within the project 'Soil in Balance?' a group of growers started using the Albrecht method for soil analysis. Striking is the concluding sentence in the summary 'During the project, the emphasis shifted to a completely more resilient cultivation system.' And the latter is of course what matters.

How further?
However, this is not all. The popularity of the method also suggests that users have lost sight of good soil quality due to the presence of soil-related bottlenecks (the 'Soil in Balance' method is then seen as a potential solution). In other words: that it has lost the knowledge to properly interpret soil analysis reports and to embed this knowledge within fertilization plans. In practice I encounter both aspects.

Let me start positive. The first reason shows that entrepreneurs see prospects in sustainable soil management. The moment they start looking at the soil in concrete terms (using the 'Soil in Balance' method as a first approach), it appears that the soil offers possibilities to increase crop yields and to be less vulnerable to large fluctuations in weather.

More than a world of nutrients
Soil quality is more than just a world of nutrients. It is therefore a very positive development that this integral quality of the soil is increasingly coming into the picture. I see this happening within dozens of study groups with farmers, within research projects such as PPP Better Soil Management, as well as in the development of integrated soil valuation instruments.

The Open Soil Index, for example, provides insight into the functioning of more than twenty chemical, physical and biological soil functions for every plot in the Netherlands. If every user of the 'Soil in Balance' method comes to the realization that the soil quality is much more than the ratios between cations (and adjusts his or her management of the soil and fertilization accordingly), its use will ultimately even have a positive effect. effect.

The second possible reason is that many agricultural users have lost the soil knowledge to properly interpret and value the parameters of a soil analysis form. In recent years I have been able to supervise dozens of study groups, the majority of which really did not know how to properly interpret the results of a soil analysis form.

Analyzes stored in the cupboard
The bars used that describe the soil condition (on a scale from low to high) do give rise to many suggestions. What a measurement actually means for soil quality, as well as how they can (and should) act on it, raises many questions in practice. As a result, the soil analysis reports are neatly stored in the cupboard and the knowledge contained in them is not used.

It is more worrying if many agricultural entrepreneurs only have their soil analyzed for nitrogen and phosphate, because it is simply necessary and the analysis is only done to determine how much manure can be used. This is also a very common practice. In my opinion, this can only happen because they apparently do not know (anymore) what valuable information about soil quality can be derived from a soil analysis report.

I must say here that the current soil analysis reports as well as the manuals and fertilization recommendations of the Fertilization Committees (CBGV and CBAV) do not make it easy for an entrepreneur to practically translate this knowledge into an optimal fertilization plan. There are still many opportunities here. 

Conclusion
From an agricultural point of view, it is not desirable to design fertilization according to the well-known concept of 'the Soil in Balance' or the Kinsey-Albrecht method. This is because the balancing method does not improve crop production and even leads to unnecessary fertilization costs.

However, its popularity also shows that there are major challenges for researchers, consultants and universities of applied sciences in communicating the measurability of soil quality in a clear and simple manner, including the associated action perspective (how can I control soil quality as an entrepreneur). 

This blog was created after intensive discussions with my colleague Wim Bussink and builds on recent research by NMI and PPO, financed by BO Akkerbouw. As described in: Bussink DW et al. (2020). Effects of fertilization K, Mg, Ca, N, Cl and their interactions on crop yield and quality. NMI report 1763.N.19, 48 pp.

Gerard Rose

Senior project manager in soil, water and agriculture at the Nutrient Management Institute (NMI).

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