Plants recondition the soil, altering plant-soil feedbacks

Plant-soil feedback is a powerful concept to capture plant-induced change in the soil and their knock-on effects on plant performance. Most knowledge on plant-soil feedbacks comes from greenhouse studies where a single plant is tested on the soil conditioned by another single plant (of the same or a different species). This study shows that soil conditioning effect can carry-over through time and that it depends on the preceding combination of species what the soil feedback will be.

It is well known that as plant grow they modify the soil in their immediate surrounding, both abiotically and biotically. This process is continuously going on and the soil composition is thus continually reshaped. For example, when the roots of a new species come in it will modify the local soil microbial community composition in new ways depending on e.g. the chemistry of its root exudates. However, the continuity of this process is poorly documented and its consequences are quite unknown.

This study shows that the particular sequence of plants that have conditioned the soil in the past is very important in determining the current soil feedback. For instance, if species A and B are growing in different patches and species C takes over both patches, most models would only include the soil feedback that C exerts on the subsequent plant growing there. However, it turns out that whether species A or B had been growing there before can also importantly affect the local soil feedback.

We think this may explain why when different soils are conditioned by the same species the resultant soil feedbacks can be quite different. In addition, it may explain the rather erratic species replacements seen in long time series on permanent plots. Field-based studies are now needed to quantify how large this effect is under natural conditions.

Jasper Wubs

More info: https://nioo.knaw.nl/en/employees/jasper-wubs

Twitter: @JasperWubs

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