Distinct Element Method Modelling of Soil-Tool Interaction and Soil Movement during Tillage

With the help of computer modelling researchers try to describe how individual soil particles react when the field is cultivated by agricultural machinery. They hope that the technology can be used as an alternative to practical field experiments in the process of designing new agricultural machinery.

Tavs Nyord heads an industrial postdoc project, the purpose of which is to develop computer simulation methods that can describe soil movement and draught forces during soil tillage.

How do soil particles in a field react when agricultural machinery is used for soil tillage? The answer can be found with the help of a computer model that simulates how the particles move individually and in relation to one another. At the same time, information about the force transferred to the machine can be estimated and used in the design of new equipment.

So far the researchers have tested the method to analyse the soil cutting forces and how the soil is moving during injection of slurry in three selected types of Danish soils.

The computer model can be very important in the development of new agricultural machinery and tools for a more effective and sustainable food production. Knowing how the soil reacts to external forces provides a good prerequisite for optimising the preparation of the soil and thereby the crop yield.

Bringing the field to the desk
As part of an industrial postdoc project, the researchers will develop a computer model that is able to predict the soil cutting force during different kinds of soil tillage in soils from different geographical locations.

The three types of soil are placed in a so-called semi field facility in which a slurry injector is driven in.

The data from the soil moving measurements and the soil cutting forces are entered in the computer model which then visualises what happens to the soil under the actual conditions.

How the computer model works
For example, the model can indicate how the soil particles "fall down" after the slurry injector tine has been driven through the soil. It is possible to see whether the soil covers the slurry depending on different working depths, water content, texture etc. and assess whether it is possible to place the slurry less deeply in the soil and thereby reduce ammonia and odour emission from the slurry effectively.

Computer-based visualisations can in many cases replace the existing physical trials and thereby reduce cost and time in improving the design of new machinery.

The world is waiting for more efficient farming

The number of people in the world increases together with average prosperity, which in turn leads to increased pressure on the supply of food. At the same time, there is a growing demand for biomass for energy production and in order to meet the global demand for agricultural products, it is necessary to make plant production more efficient rather than appropriating an even larger area of land for cultivation.

A critical factor for the efficient production of foods and biomass is that the working of the soil is energy efficient and has a high quality. Researchers from Aarhus University are in front when it comes to procuring knowledge for the development of machinery and tools for working the soil.