Aarhus University Seal / Aarhus Universitets segl

Yue Xie


Yue Xie


University: Aarhus University

Department: Department of Food (FOOD)

Supervisor: Hanne L. Kristensen, Associate Professor, FOOD

Co-supervisors: Jørn Nygaard Sørensen, Senior Scientist, FOOD

Project term: January 2013 – December 2015

Education: Master Degree in Agronomy, China Agricultural University, China



Vegetable production often has high leaching losses of nitrate to the environment due to high fertilizer demand, low nitrogen (N) use efficiency and incorporation of N rich plant residues. However, in recent years several tools have become available to reduce N leaching losses, like autumn catch crops, design of crop rotation and reduced fertilizer rates, which has made it possible to substantially increase the N use efficiency of vegetable productions systems. However, crops like leek and late season cauliflower pose challenges beyond these tools due to the demand of high N availability during the entire growth season and late harvest date to ensure high yields and quality. This leaves high amounts of nitrate in the soil in autumn and no time for growing of autumn catch crops. In organic vegetable production, intercropping systems with a cash crop and catch crop growing in alternating rows at the same time in the field, have been shown to reduce N leaching and improve natural pest management. Yields and quality of the produce in such intercropping systems have been found to be acceptable to high, when root competition is controlled by root pruning of the catch crop, displacement of sowing date of the two crops, or increased spacing. However, little is known about the N competition of cash and catch crops over time and space, especially for the high N demanding and late harvested crops like leek and late season cauliflower.



The aims with the project is to increase our understanding of the timing of root and N competition of cash and catch crops in intercropping systems for organic vegetable production of high N demanding and late harvested crops.


Research outline

The effects of catch crops on reducing nitrogen leaching are investigated in two year experiments. Leek and Cauliflower are intercropped with catch crops (Isatis tinctoria and second year legume/grass green manure), respectively. Different sowing dates of sowing and root pruning of the catch crop are applied to control the competition between cash and catch crops. The yield, soil N during the growing season and leaching season and N accumulation in plants will be investigated. The detailed study of root development is also followed. Greenhouse experiment will be carried out for more detail on plant competition and nutrient use efficiency.


Partners of collaboration

University of Maribor, Slovenia

University of Kassel, Germany

University of Bologna, Italy

Centro per lo studio delle relazione tra pianta e suolo (CRA-RPS), Italy

Styttes Gartneri, Denmark

View all (13) »

View all (2) »

ID: 50960372