Tree-fungus supplement could reduce fertilizer use in tomato crops

By Ben Coxworth

Although Ceriporia lacerata fungus causes tree wood to rot, it also has a good side. According to a new study, adding the fungus to agricultural soil allows tomatoes to be grown using much less fertilizer.

Partially because they have such a long growth period, tomato plants require more nutrients than many other crops. As a result, farmers typically apply large quantities of chemical fertilizer to their fields.

Not only is this time-consuming and expensive, but it also reduces populations of beneficial microbes in the soil, plus it causes pollution as excess fertilizer runs out of the soil and into waterways. Additionally, even though chemical fertilizers may indeed boost tomato yields, they often reduce fruit quality.

Led by Jianguo Huang, scientists at China's Southwest University instead looked to a specific strain of the Ceriporia fungus which is harmless to tomatoes.

Ordinarily, when growing on trees and when present in the soil, it emits enzymes such as proteases and phosphatases to obtain nutrients from the immediate environment. In the course of doing so, it frees up nutrients – including those previously delivered in fertilizer – which would otherwise have remained "locked up" within naturally occurring compounds in the soil. Those nutrients can then be taken up by plants.

In field tests, it was found that when the HG2011 strain of Ceriporia lacerata was added to both fertilized and unfertilized soil, it improved the nutrient uptake and thus the yield of tomato plants growing in that soil. Importantly, the fungus also enhanced the nutritional value and flavor of the fruit by increasing its sugar-to-acid ratio along with its soluble sugar and vitamin C content.

It is now hoped that compost incorporating the fungus could be used in an inexpensive supplement, which would reduce the need for traditional fertilizers.

A paper on the research was published in the Journal of Agricultural and Food Chemistry.