Majken Deichmann


Majken Deichmann


Title: The influence of drainage management and N-fertilization on crop production and nitrogen leaching based on case studies in China and Denmark


Leachingof nitrogen (N) from agricultural production to surface and groundwater is a global environmental challenge. In Denmark measures for reducing N- leachinghave resulted in a reduction of more than 50% since the 1980’s. Denmark is still faced with the goals of the European Unions (EU) Water Frame Directive (WFD) while Danish farmers are complaining saying that the Danish agricultural regulation is so strict that it limits their ability to compete in a global market. New measures for reducing N leaching is required to balance the needs for agricultural production and environmental protection. Controlled drainage have successfully been tested in other countries (U.S.A, Canada, Italy and Sweden), resulting in increased yields and reduction in N leaching. However, controlled drainage has until now only been applied to spring crops.  This research will address the use of controlled drainage in winter wheat production as winter wheat is the most common crop in Denmark and N leaching is highest during the winter season in Denmark. While controlled drainage might have the potential to lower the N-leaching it could also result in periods of waterlogging when applied during  the Danish winter season as the precipitation is high. Previous studies on waterlogging from the United Kingdoms, reports of server decreases in winter wheat yields after a waterlogging period of only five days. Consequently, the research will include studies of the effect of waterlogging in winter wheat production.

A similar study will be conducted under Chinese conditions.  China accounts for 22% of the world’s population but holds only  7% of all arable land, resulting in zones of intensive agriculture with high N-fertilizer inputs, which is further endorsed by Chinas policy of being self-sufficiently regarding food production. Consequently, N-pollution of both surface and groundwater has become an issue in China.  The contradicting priorities of food production and clean surface and groundwater indicate that China like Denmark is faced with the challenges of finding new ways of managing N- leaching which won’t affect the agricultural production.  China is the largest producer of wheat and wheat is a typical winter crop in China. Southern China is faced with high precipitation during winter and waterlogging in winter wheat production is a shared challenge between China and Denmark.

The aim of the research is to evaluate whether controlled drainage could be a  management tool under Danish conditions, by determining whether it can reduce the N leaching without adverse effects on the agricultural production when applied on winter crops under Danish conditions. Also,  the research aims at determining the negative consequences which waterlogging may have on the winter wheat yield in China while considering how it affects the N-dynamics in the soil. 

ID: 93265050