VEGETATION AND SOIL DATA
Measurements of vegetation properties were carried out by the Department of Vegetal Production in the School of Agricultural Engineering in Albacete and the Department of Thermodynamics of the Faculty of Physics of the University of Valencia.
The type of vegetation in the area was composed mainly by Corn (dry and irrigated) and Alfalfa, there were several fields where cereals were grown in winter and were not covered by vegetation at the time of the experiment.
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The measurements were focused on the vegetation properties, in terms of canopy structure and coverage, as well as in energy balance. The properties measured were plant cover percentage, height, LAI, biomass, water content and chlorophyl content, and photosyntesis. Physicochemical and other soil surface properties measurements (roughness, soil mositure) were also measured in selected plots.
The actual situation of the measurement conditions (state of the ground, atmosphere, etc.) were recorded with the video camera, and many photographs.
ALFALFA MEASUREMENTS (fields 3 & 4):
LAI was measured along a diameter in the north-south direction.
- Plant water content and biomass were measured by weighting before and after cutting and drying half a squared meter of plants at the ground level. Two samples were taken in field 3 at both sides of the center in the north-south transect of the pivot. In field 4 six samples were taken in a transect crossing the field in the longest direction.
- Soil moisture. In field number 3 soil moisture was measured across the first 15 centimeters from the surface with a time domain reflectrometer along a transect.
- Height. In field number 4 height was measured following the same transect where the rest of the measurements were carried out.
CORN MEASUREMENTS (Field 1):
Soil moisture, the first 15 centimeters of the surface were measured along the circumference with a time domain reflectrometer. Twelve measurements of soil moisture were taken following a circumference with the same center that the pivot (seventh irrigation circumference from the border of the field)
- Biomass and water content was measured by cutting and weighting separately each part of the plant.
- LAI was measured in field number 3 with a LICOR LAI-2000 along a diameter following northeast-southwest direction.
- Photosynthesis and transpiration was measured with a Leaf Chamber Analyser, model LCA 4 of ADC Ltd. These measurements were carried out on 12 August 1998, just one day after the flight, due to instrument problems. However, since no changes in the surface happened during this time, with similar atmospheric and solar illumination conditions the results should be valid.
- Temperature of vegetation was measured at three levels: top leaves exposed at direct solar radiation, lower levels shadowed leaves, and shadowed soil and illuminated soil. Four temperature data in total for each vegetation plot.
