The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B7. Beijing 2008
The
980
Shandong
128.56
Henan
156.79
Jiangsu
143.83
Anhui
140.92
total
106.83
Table 1. The average cropping index of each province from
1982 to 2003
C~~~1 CI= 0 r~1 C/=100 mm CI=200 non-arable land
Fig.6 The spatial distribution of the cropping index in Northern
China inl982, 1990, 1997, and 2003
4.3 Cropping Index Change Trends
The change trends for cropping index are shown in figure 7,
figure 8, figure 9, and table 2. The northern China experienced
an obvious cropping index increase, from 87.27 in 1982 to
115.98 in 2003 with an average change rate 1.3275 per
year(7? 2== 0.7955, .P<0.001) (Figure 7). Inter-Mongolia, Hebei,
Shandong, Henan, Jiangsu, Anhui experienced most significant
increase, comparatively, Liaoning, Shanxi, Ningxia no
significant increase (Table 2). From the histogram of VCI
(Figure 8), about 25.95 percent pixels of the whole arable land
in northern China had positive values greater than 2, indicating
an increase of cropping index. On the contrary, only 2.43
percent had negative VCI less than -2, and the rest 71.62
percent falls into the interval [-2, 2]. Figure 9 shows the spatial
distribution of VCI. During these 22 years, a large increase in
Cl happened in Huang-Huai-Hai drainage area, a large decrease
in a small quantity of pixels of Henan and Shanxi provinces,
and no visible changes in other regions.
Figure.7 The variation of total northern China cropping index
from 1982 to 2003
Coefficient
R 2
P
Heilongjiang
0.394
0.129
0.100
inter-Mongolia
1.629
0.596
0.000
Xinjiang
0.630
0.567
0.000
Jilin
-0.067
0.115
0.123
Liaoning
0.000
0.000
0.990
Gansu
0.603
0.165
0.061
Hebei
2.686
0.628
0.000
Beijing
1.914
0.375
0.002
Shanxi
0.028
0.001
0.912
Tianjin
1.134
0.375
0.002
Qinghai
0.423
0.127
0.104
Shaanxi
0.617
0.103
0.146
Ningxia
-0.009
0.000
0.977
Shandong
3.044
0.673
0.000
Henan
2.236
0.637
0.000
Jiangsu
2.618
0.462
0.001
Anhui
1.938
0.483
0.000
Table 2. The regression coefficient of each province cropping
index from 1982 to 2003
N°
O'-
C
U
u
V-
u
D.
decreasing
increasing
71.62
2.43
25.95
Li
1 A
-12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12
VCI
Figure.8 Histogram of cropping index change trends
Figure.9 The spatial distribution of cropping index change trend
during 1982-2003
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