Basic instrumentation and measurements

A cabin will be installed at the site for protection of measuring equipment. Electricity, a CO₂ supply system for the FACE and a water tank for the irrigation system will be installed. Telephone connections will be installed for surveillance and automatic data transfer. A series of basic measurements will be initiated and used for data evaluation and treatment documentation. All measurements will be stored as average, max. and min. values in data loggers at appropriate time intervals. Basic instrumentation and measurements include:

• Meteorological parameters – A 3m high meteorology mast will be erected at the site and equipped with the following sensors: Air temperature, wind direction, wind speed, relative humidity and PAR. The data will be used simultaneously in the FACE control system, but also stored as 10 min average with maximum and minimum values in a data logger.
• Nitrogen deposition – wet deposition (funnels for precipitation input of NO₃^- and NH₄⁺) and dry deposition (passive samplers for NO_x and NH₃) will be monitored on a monthly or biweekly basis.
• Air and soil temperature in treatment plots will be measured continuously. Detailed studies of the temperature distribution patterns will be done.
• CO₂ concentrations in treatment plots will be measured continuously to regulate fumigation and to document treatments. Specific studies on CO₂ distribution patterns will be done in campaigns.
• Soil moisture in various depths will be measured continuously by TDR to be used for data-evaluation of treatment effects, documentation of treatments and hydrological modelling.
• Water input to treatment plots will be sampled in each plot by funnels to control and document treatments
• Net radiation balance will be measured in a few selected plots.
• Surface temperature will be measured in a few selected plots.