The objective is to provide representative data on denitrification and nitrogen emission from agricultural land in different countries in the European Community which, together with the other variables intensively monitored, will make possible the establishment of a database and permit the calibration and evaluation of 3 different denitrification models.
In order to provide representative data on dentrification and nitrogen emission from agricultural land for a database, emission of nitrous oxide and denitrification have been measured by a soil core method according to common methodical protocol. A cover box technique has also been used for direct field measurements of nitrous oxide emission. Field registrations of the following variables have been made: air temperature, soil moisture content, precipitation (or irrigation equivalent) and estimated evapotranspiration, content of inorganic nitrogen (ammonium and nitrate). Nitrous oxide emission has been measured from February to December with 2 week intervals. Very high fluctuations were found from the experimental sites in all countries. Maximum values for nitrous oxide emission was found to be at approximately the same tie in all countries, March to April, and with low levels during the summer.
The work will consist of:
the measurement of the emission of nitrogen monoxide, nitrous oxide and nitrogen from land surfaces in different European cultivation systems and soil types under closely monitored environmental conditions;
laboratory experiments to evaluate the effect of different environmental parameters and organic amendments on the nitrogen emission;
and testing of 3 existing nitrogen models for their capacity to predict the nitrogen emission.
The studies will be focused on those agricultural cropping systems which are known or suspected to have a high capacity for nitrogen emission. These include heavy textured soils, soils receiving large inputs of organic manures, and soils under grass.Initially a comparison of the methods for the estimation of nitrogen and nitrous oxide fluxes from soil, in laboratory experiments as well as in field experiments, will be made using nitrogen-15. This will enable the participants to select the best method and use it in common. The methods that are going to be compared during the first year are the gas sampling probe method with probes at different depths, the soil core method and the soil cover box method (both open and static). Electron capture detectors will be used for nitrous oxide measurements and mass spectrometry will be used to measure nitrogen-15 compounds, while nitrogen monoxide will be measured using a chemiluminescence analyzer.
Denitrification and nitrogen emission will be measured by all the participants using the best technique from the above mentioned evaluation. All experimental sites will be characterized according to guidelines set up for the input requirements to the ANIMO model. These include climatic measurements, soil physical and chemical measurements, crop data, and management data.
All nitrogen emission measurements together with the auxiliary data will be stored in a database using published guidelines.
Funding SchemeCSC - Cost-sharing contracts
AL5 2JQ Harpenden, Herts