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Machine design and crop choice can reduce soil compaction

Heavy agricultural machinery used to cultivate the soil, apply animal manure and harvest crops contributes to the degradation of farmland. Innovation in relation to technology and crops can help remedy this serious problem.

2016.10.12 | Janne Hansen

Farmed soil is under pressure from heavy agricultural machinery. Collaborative efforts between scientists, businesses and advisers aim to find solutions to the problem. Photo: Per Schjønning

Danish soil is under pressure – literally speaking. The heavy agricultural machinery that is supposed to provide a solid basis for a productive harvest actually contributes to the exact opposite. The heavy machines compact the soil leading to long-term and even irreversible damage. 

Scientists from Aarhus University are leading a new project the aim of which is to develop methods to prevent and remedy the damages caused by soil compaction. Project participants include scientists as well as companies within the fields of machinery, tires, seeds and advisory services. The project partners aim to solve the problem of soil compaction by means of new technologies as well as a targeted use of crops. 

Danish soil has a problem

Soil compaction is one of the most serious threats to sustainable plant production as it reduces crop yield and quality and is harmful to the environment. Especially soil compaction below the tillage depth constitutes a major problem as the damage is long-term and very difficult to remedy.   

In Denmark soil compaction is a widespread phenomenon. It is one of the worst threats to Danish soil quality and a contributory cause of stagnating harvest yields. The environment suffers from the effects of erosion, leaching of nutrients and other compounds to the aquatic environment, and greenhouse gas emissions to the atmosphere. 

Technological innovation

It is commonly known that both tire pressure and wheel load contribute significantly to soil compaction. Wheel loads of six tons are common and even the double of this load can occur. Often farmers use too high tire pressures to facilitate traffic in the field. In wet conditions, this causes compaction in the plough layer as well as in the subsoil. In addition, it turns out that the risk of compaction increases significantly when field traffic increases. Innovative measures are needed to ensure improved distribution of the weight impact on the soil. 

The project partners aim to develop a new design for vehicles transporting straw and grain crops. These vehicles will combine high capacities with a minimal level of soil compaction. The design will build on a patent pending concept which will be further developed, tested and validated during the project. 

Plants set to work

The project will not only focus on machinery. Crops will also be given some tasks. 

Plant roots from the main crop or catch crops can improve the quality of the compacted soil by establishing tiny pores in the soil and increasing the formation of an improved soil structure. Previous studies have demonstrated that deep-rooted plants such as chicory, alfalfa and Brassicaceae plants (e.g. rapeseed, cabbage, Sinapis) have a positive effect on soil structure. Increased earthworm activity may be expected when growing catch crops. However, the question is to which extent the plant roots are actually able to improve soil structure in soil with serious compaction damages. Therefore, part of the project will be to examine this in field trials.

The project will apply the Daisy model to predict the impact of compaction and biological soil loosening on yield and environment. 

Practical use of knowledge

The project focuses strongly on the application of solutions to reduce compaction problems. This will be accomplished by developing the decision support system Terranimo® (www.terranimo.dk) in close cooperation between farmers, advisors and scientists. In addition, solutions for minor compaction problems will be demonstrated. 

The four-year project has received a grant of 11.7m DKK from the Green Development and Demonstration Programme (GUDP) and will be carried out in collaboration between Aarhus University, University of Copenhagen, Green Agro & Transport, Jysk Landbrugsrådgivning, Seges, DLF and Michelin.

Further information please contact: Senior Researcher Lars J. Munkholm, Department of Agroecology, email: lars.munkholm@agro.au.dk, telephone: +45 8715 7727, mobile: +45 2515 2716

Agro, DCA, Technology