The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B7. Beijing 2008 
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2. MATERIALS AND METHODS 
2.1 Study Area 
The study area is located in Huimin County (PR China), close 
to the Yellow River (Huang He), in the northeast of Shandong 
province, which is part of the NCP (Fig. 1). The climate could 
be distinguished as a warm-temperature sub humid continental 
monsoon climate with a mean temperature of 12.5°C and an 
average yearly precipitation of approximately 600 mm. 
Predominantly precipitations occur in summer. The farmers in 
this region operate a traditional cropping system with a summer 
maize and winter wheat rotation. Winter wheat is sown after 
harvest of summer-maize in autumn (in late September) and is 
harvested in early June. Winter wheat is irrigated during the 
drought in spring. 
2.2 Experiments 
The field studies consisted of three small size experiments with 
varying N-application and different regional winter wheat 
cultivars. The plot size within the experiment field’s ranges 
from 28 m 2 to 170 m 2 .Fields of experiment 1-3 were located at 
Xizhangliu village in Huimin County for the years 2006 and 
2007. 
Experiment I 
In this experiment the influence of manuring with five nitrogen 
treatments (0, 5, 25, 75, 100 kg N/ha) and four replications on 
Weimai8 winter wheat cultivar was investigated. Each plot 
(10 m by 15 m) has been fertilised before planting. During 
growth stage 6 (Large, 1954) half of the plots received 
topdressing with nitrogen fertiliser again. 
Experiment 2 
In experiment 2 the amount of N-fertilisation was surveyed on 
two varieties of winter wheat (Kenong9204 and Lumai23). Each 
plot was divided in six smaller plots. Each small plot (4.5 m by 
7 m in 2006 and 4 m by 9 m in 2007) has been manured with a 
different rate: 
No N (control) 
40% of optimum N rate (Opt) 
- 70% of Opt 
Opt 
130% of Opt 
Conventional N rate (con). 
Experiment 3 
The fields of this experiment represent the common cultivation 
method for this region. All fields belong to different farmers 
using different varieties of winter wheat and varying rate of 
N-fertiliser. The planting date differs according to the practice 
of the individual farmer. 
In 2006 three farmers’ fields (Expt4) and four in 2007 with an 
area between 2.5 ha and 4.5 ha have been additionally 
examined for satellite image analysis. Six different cultivars 
Jimai20, Jimai21, Lumai8, Lumai23, Weimai8 and Zimail2 
were planted on these fields. All fields were managed by 
farmer’s common practice. Image acquisition of multispectral 
data with IKONOS, EO-1 ALI and ASTER, hyperspectral data 
with Hyperion and radar data with RADARSAT and Envisat, 
has been performed simultaneous to the field data collection. 
2.3 Field measurements and data collection 
2.3.1 Spectral reflectance measurements: High resolution 
spectrometers from Analytical Spectral Devices Inc. (ASD) 
were used for taking spectral measurements, a Handheld 
FieldSpec (range 325 nm to 1075 nm) in 2006 and a 
QualitySpec (range 350 nm to 1800 nm) in 2007. The 
hyperspectral devices detect the electromagnetic spectrum from 
visible (VIS) to the near/shortwave infrared (NIR/SWIR) with 
512 channels for FieldSpec and one TE cooled channel for 
QualitySpec by using optical fibre cable. The default FOV 
(Field Of View) of the devices with an angle of 25° was used 
for the measurements. The sensor was fixed by an orthogonal 
construction 1 m above the crop. It consists of three brass-poles, 
which were combined with moveable joins to a triangle 
(Laudien, 2005). A mounted sprit-level allowed reliable vertical 
spectra acquisition. The acquisition geometry is specified by the 
apex angle and measuring height (see Eq. 1). Consequently the 
acquisition radius amounted to 22.2 cm for the measurement 
and the acquisition area to 15 square centimetres (see Eq. 2). 
Continuous calibration measurements of optimisation by a 
white reference panel (BaS0 4 ) and of dark current were taken 
depending on illumination changes. The measurements were 
taken at noon from 10 am to 2 pm under cloudless conditions. 
For each plot three measurements were done in order to reduce 
the influence of atmosphere (clouds, wind, etc.) and field 
conditions. The spectra were collected at feekes growth stage 
3-11 (10 measurements for Exptl-Expt3, 8 readings for Expt4 
in 2006 and 6 measurements for all experiments plots in 2007). 
Approximately 14’000 spectra have been acquired for 2006 and 
2007. 
r [m] = h * tan(a/2) (1) 
A [m 2 ] = 7t * r 2 (2) 
with r = radius, h = measuring height [m], 
a = apex angle [°], 
A = acquisition area 
2.3.2 Agronomic parameter’s measurements: Agronomic 
measurements, including soil moisture, chlorophyll content, 
LAI (leaf area index), plant height, row distance, biomass and 
soil samples were combined with spectra measurements in 2006 
and 2007. Soil moisture was measured by moisture meter 
(Delta-T Devices) in 2006 and with Aquaterr T-300 in 2007. 
Chlorophyll content readings using SPAD 502 (Minolta) were 
taken at mid-length of the uppermost fully expanded leaf from 
30 randomly selected plants and averaged to one value for each