Soil compaction causes on average 10 - 20 % yield loss, but can even reach 60 %! 

Soil compaction occurs when external forces exceed the internal soil strength and presses soil particles together. This results in the loss of air and water containing soil pores. 

As a consequence compacted soils provide poor growth conditions for crops as the roots neither can spread easily into the soil area, nor have sufficient access to water and nutrients (Fig. 1).

Fig. 1: Plant growth on healthy soil compared to compacted soil (caused by plowing). On compacted soil, roots can not enter the entire soil area and have less access to nutrients and water.

How to know if the field is dry enough to enter with machinery?

Just feel it! For soils with medium textures (not too sandy, not too clayey), you can take a handful of soil to assess the field’s moisture conditions and thus the potential for creating soil compaction. Take a probe of soil from the top 30 - 50 cm and simply roll it against the palm of your hand:

• If the soil is fragile and falls apart, soil moisture is rather low, you can enter the field without damaging the soil structure!
• If the soil clumps together it is more prone to compaction.
• If you can even form a smooth roll of soil without cracks, the soil is far too wet! Entering the field under these conditions might cause more problems than it will solve!

Can AMALGEROL protect against soil compaction?

Certainly not alone, but it can increase soil stability and help to maintain a loose soil! 

At the Inn valley in Tyrol, one of the most important regions for vegetable production in Austria, we compared the soil of two adjacent carrot fields. One field has been treated with AMALGEROL for several years (the farmer is a convinced AMALGEROL-user), while the neighbouring field has never been treated with AMALGEROL. 

The penetrologger profile in Fig. 2 clearly shows that with the "AMALGEROL soil" (green) much less pressure is needed to penetrate the soil than with the untreated soil (gray).

The AMALGEROL soil is therefore looser, especially in the upper 20 cm where the carrots grow. In comparison, the untreated soil is already strongly consolidated at a depth of 10 cm, which is expressed by twice the force. This was also confirmed by the growth habit of the carrots (Fig. 3).

Fig. 3: Carrots on the left grew on the untreated field and show a somewhat compressed tip. Carrots on the right grew in the long-term AMALGEROL-treated soil and are well developed and significantly longer.

The important role of humus against soil compaction

Humus or organic matter, respectively, stabilizes the soil structure. Humus particles are crucial for the formation and stabilisation of soil aggregates. Together with clay minerals they are building the so-called "clay-humus-complex". The higher the organic matter content of a soil is, the more stable are the soil aggregates and thus the soil as a whole. Consequently, soils with less stable soil aggregates are more prone to compaction. In addition, humus stores water and nutrients, and can therefore compensate soil compaction to a certain extent. 

Concerning soil textures: Clay is most susceptible to soil compaction, particularly when wet, because clay minerals absorb water and become unstable (slippery). Increasing the content of organic matter stabilizes the structure of clay-rich soils and elevates their bearing capacity. 

Sandy soils have a lower water holding capacity and are therefore less prone to compaction, yet not immune. With a naturally lower nutrient holding capacity, sandy soils will likewise benefit from an elevated organic matter content, as it not only prevents soil compaction, but also increases nutrient availability.