‘Dutch agricultural soils are not future-proof’ was a widely accepted statement at the final meeting of the Public Private Partnership (PPP) Sustainable Soil. Breeders, chain partners, suppliers, the government and the science sector see a gradual deterioration in soil quality and are joining forces within the PPP to find a solution. “It isn’t a simple matter,” says coordinator Wijnand Sukkel of Wageningen Plant Research.
The extensive soil programme has resulted in various research projects over the past few years, which have been made accessible via the website www.beterbodembeheer.nl (Dutch only) along with the knowledge gained. Farmers and advisors, for instance, can consult the site for information on alternatives for chemical soil decontamination, the best use of green fertilisers or the application of non-inversion tillage. In addition to methods and background information, the website also provides insight into costs and benefits of soil improving management. This is crucial as farmers looking to invest in the soil must also manage short term costs in order to survive and need to have insight in the long-term economic effects of soil improving measures.
Measuring soil quality
A focal issue in the PPP is the biological component in the soil. In contrast to the chemical and physical aspects, this is receiving relatively little attention in agriculture, even though soil life plays a major role in converting organic substances, forming the soil structure and combating soil-related diseases. Joeke Postma of Wageningen Plant Research provided a clear illustration of several management strategies, and especially amendments with organic matter, and how they influence the activity of the soil life and can support soil suppressiveness against diseases. The composition of the soil life can be an important indicator of the condition of the soil. On this basis scientists see an opportunity for making the biological quality of agricultural soils ‘measurable’ and ‘manageable’.
Farmers need support
As several issues related to soil quality are outside the direct sphere of influence of farmers, participants in the PPP stress the importance of cooperation. Agriculture is affected by changes in the climate, regulations, new soil use and functions, as well as an increase in short-term land lease agreements. Combined with an intensive production process, these factors all contribute to deterioration of soil quality, or to changing demands on soil quality.
According to Sukkel further research can help get more grip on the complex soil processes. Research into the interaction between organic matter management and mineral fertilisation, for example, can help to reduce nitrate leaching, N2O emissions and increase nitrogen use efficiency and carbon sequestration. Insight in the interaction between soil tillage and root de development of cash crops and cover crops can help in combating subsoil compaction. At the same time, he believes a transition to soil improving genotypes (varieties) and more soil-friendly mechanisation is required. “For this we also need the breeders and machinery manufacturers.”