Quantification of potential nutrient cycling from deep soil layers by different plants and systems


Quantify potential use of resources from the deep soil layers by different species and cropping systems and assess the potential environmental improvements in terms of nutrient cycling

A main point of the project will be studying resource use from the deep soil layers. Currently our knowledge on deep rooting is limited, but our knowledge on actual resource use from these layers is almost absent. Some studies have been made on use of nitrogen (N) and water down to around 2m depth, but rarely more and practically nothing have been made on other nutrients.

To make sure the studies of resource use become successful, we will work with some methods which are well known and which we know can give such results. The use of 15N and traditional soil water measurements represent such methods.

We will combine the well known methods with other isotope methods which can give more information. We will prioritize methods which can give us better data on plant uptake of immobile nutrients such as P or K and more dynamic data on water use.

These studies will rely on the DeepRootLab to a large extent, making use of the detailed root studies which will be made (WP2) and the broad range of study methods made available there. Still, some aspects we may study using the mobile facility and the experiments described in WP4. We will also use the mobile facility to quantify effects of including deep rooted intercrops in existing long-term crop rotations experiments such as the cropping system experiment at Research Center Foulum (Olesen et al., 2000).

It will be a specific goal to document the effects the different approaches for achieving deep rooting through choice of plant species, cropping systems or sowing date on deep resource use, and make quantitative estimates of resource uptake from deep soil layers.

WP leader: Kristian Thorup-Kristensen