Soil fungi reduce the leaching of fertiliser to the groundwater, and consequently help to alleviate the environmental problems of conventional agriculture. This was shown in a PhD study by Franciska de Vries of Wageningen University, which she will defend on 27 February.
Minerals from fertilisers such as nitrogen are leached into the groundwater and can then enter surface water in adjacent areas, with negative consequences for the health of ditches and rivers. This is especially harmful to the species diversity of nature reserves.
Because a great amount of fungi is present in the soils of nature reserves, it was often assumed that the presence of many fungi in an arable field or pasture is an indicator for ‘sustainable’ agriculture. Franciska de Vries has now shown for the first time that this assumption is indeed correct: "My research has shown that the populations of fungi in the soil increase if farmers fertilise their grasslands less frequently, and that fertiliser leaching is also reduced. With the same level of fertilisation, there is clearly less leaching in a soil with many fungi than in a soil with few fungi. It appears that the fungi themselves reduce the leaching of the fertilisers; they do not break down the manure as quickly because they can retain the minerals in their hyphae (mycelium). It is therefore beneficial for farmers to ensure that the populations of fungi increase in their soil. This is especially the case now that more agriculture, and more intensive agriculture, is required due to the increasing global demand for food and biofuels.
Greenhouse experiments showed that the yield did not initially decline with less fertilisation and higher populations of fungi. However, De Vries adds a note of caution: "It is very probable that this will lead to yield reductions over the long term. The next step in the research is therefore to search for a type of soil management that promotes the growth of fungi, but does not lead to a reduction in crop yield."
For more information, please contact:
Franciska de Vries, Wageningen University (current work address Lancaster University, United Kingdom), tel. 0317 842364 or