What is heavy machinery

Problem in agriculture : Heavy machines: floors lack the air to breathe

The use of heavy equipment means that soil compaction continues to increase in this country - the consequences affect everyone and can have fatal consequences.

by Rainer Horn
September 09, 2015, 1:32 p.m.

Kiel | Although the United Nations proclaimed 2015 as the “International Year of Soil”, we still pay little attention to it. The ground is slowly running out of air. He has a problem that, in addition to the discussion about pollutants, overfertilization or monocultures, is often not even noticed: He collapses.

It condenses until it contains hardly any air-carrying pores and hardly any more water can seep through because the solid soil substance has been compressed too tightly. This phenomenon is called soil compaction and is due to the use of ever larger and heavier processing and harvesting machines in agriculture and forestry.

They are called Hannibal or King Tiger, are very strong and make life a lot easier for us. Because Hannibal and King Tiger manage to harvest wood in a few hours that we would probably have needed weeks without them.

But together with the tree weights, the lumberjack machines bring it to a weight of 35 to 40 tons. It's like stacking seven to eight elephants on top of each other. This load cannot be borne by the floors and sagging clearly visible in the form of the deep lanes.

Soil compaction increases by ten centimeters every decade

Similar problems have long been known in agriculture and have unfortunately been increasing for many decades, so that soil compaction can be found at ever greater depths. As studies in the very fertile loess soils of Lower Saxony's bordering landscapes have shown, the additional soil compaction there has increased by about ten centimeters every decade since 1970.

Today, as a result of the repeated loading and unloading, firm plate structures can already be found up to a depth of 60 centimeters, which no longer allow uniform ventilation and deeper rooting. On average, as can be calculated from this, the soils have slumped by 25 centimeters in the last 30 to 50 years compared to untreated forest locations. This means that pore spaces that used to contain air have simply collapsed.

Healthy soils, on the other hand, consist of solid, liquid and gaseous phases and fulfill countless functions in our natural balance: Complex reactions take place in them that keep various substances in a sophisticated balance: while something rots here, something grows there. Soils are important filters and buffers for clean groundwater and drinking water and provide us with raw materials. A highly compacted soil can only fulfill many of these functions to a limited extent.

Fallacy: wider tires on the machines solve the problem

But soils do not grow back. They cannot be multiplied or reproduced. If we want to grow enough food for the growing world population on the heavily used land, then there is an urgent need for action. We cannot “use up” our soil, we have to use it sustainably.

It is often argued that the greater weight of forestry and agricultural machinery can be absorbed by larger contact surfaces, i.e. thicker tires or similar. But that is by no means the case. It is true that the pressure then remains stable when viewed on the surface.

However, a much larger area is compressed, and this ultimately leads to the pressure not only propagating in greater width, but also deeper. The softer sub-floors, which are very humid due to our climatic conditions, are additionally compressed more intensively and, above all, irrevocably.

Floods are a consequence

It has long been undisputed that, as a result of soil deformation, water infiltration, gas exchange between the soil and the atmosphere, biological activity is many times lower and that agricultural yield is also fluctuating more and more frequently. In addition, the water balance changes significantly.

This can already be observed when larger and larger areas of land in the fields and in the forests are becoming increasingly wet. As a result, more frequent and more intense floods also occur in summer (e.g. the Elbe and Oder floods). Because the plate structure in the ground, as it were, rammed in, the water can no longer seep into the ground so easily and quickly.

Either wet spots then form or the water runs increasingly parallel to the slope and transports many particles with it from the upper fertile soil layer. As a result, for example, in the young moraine landscape in Schleswig Holstein, soil losses increase more than tenfold.

The consequences for agricultural yield can already be observed: although there are better varieties, more sophisticated fertilization and crop protection management, and slightly higher temperatures and a higher concentration of carbon dioxide in the atmosphere, crop yields are stagnating. In the soil atlas recently published by the Böll Foundation, a corresponding analysis shows that global earnings growth is declining.

The floors need years of protection

Of course, farmers and mechanical engineers see these traces and signs of kneading, silting up and compaction and the associated increase in erosion. The attempt to cope with the development by changing the chassis construction, however, only brought moderate success.

And so the only, easily determinable and internationally recognized approach remains the strict relation of the acting pressures to the inherent strength of the soil, which in turn depends on the soil type, cultivation, soil development and climate. As a result, it cannot be linked to a single number for all areas, but has to be calculated separately depending on the location. Only then can it be said which machines can be used without too much damage on the ground.

Even if the machine loads worldwide remained at the current level, the soil would not be able to regenerate despite all the improvements in the area of ​​tire and machine configuration. He can only recover if the soil is continuously and carefully worked over years and decades.

There are numerous approaches to this, which, of course, are the responsibility and understanding of the farmers to implement. But the population and politics also play a decisive role here: higher prices for regional, soil-friendly food and an additional bonus for farmers if clean groundwater and thus also drinking water result as a result of cheap filters and buffering through the soil - that are just two of many possible approaches. From a scientific point of view, it is relatively undisputed that something has to happen. Otherwise we could one day completely lose the ground under our feet. At least the healthy ones.