International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B7. Istanbul 2004 
  
   
    
  
  
  
  
100. —@— Dacheng 
Feixiang 
90 + —71k&— Gaotang 
= 80 Shunyi 
© —O— Wuyi 
© "m >— Xushui 
s —A— Yangxin 
9 60L 
3 
+ 50° 
>= 
2 40} 
E 
2 
“= 30 F 
L 
+ 20 F 
x 
10 Fr 
0 4 1 1 1 x 1 À L L 1 
  
  
1994 
1995 
1996 
1997 
1998 
1999 
2000 
2001 
2003 
Figure 9. Temporal change of the ratio of winter wheat sown 
area for 7 counties estimated by the method using logistic 
function on 2-temporal scattergram 
The estimated winter wheat sown area by county in this study 
would be useful for the purpose of analyzing not only spatial 
distribution pattern but also temporal changes in recent years. It 
is because the statistic data of agricultural land use after the 
year of 2001 compiled by the unit of county has not yet 
published. 
Figure 10 shows the percentage of acreage of winter wheat 
sown area in county averaged for the period from 1998 to 2003. 
It is noted that the counties having high percentage of winter 
wheat sown area were located in the mainly 2 parts; one was the 
southwestern part of Hebei Province and the other was the 
northeastern part of Shandong Province. The former part was 
located near the mountainous area and the latter was along the 
left bank of Yellow river, both of which the condition of 
availability of irrigation water was good enough. In between 
these productive regions there existed the counties where the 
winter wheat was not extensively cultivated. The major 
constraint of cultivation in this area could be the less suitability 
by the existence of alkaline soils as well as the deficit of 
irrigation water. 
Figure 11 shows the trend of winter wheat sown area by county, 
which is expressed by the subtraction of the averaged value of 
1998 to 2000 from the averaged value of 2001to 2003 and then 
divided by the total mean value. This figure depicts that the 
parts having the trend of high decrease are located in the 
southeastern side of Hebei Province and the north side of 
Shandong Province. It is also noted that the rate of change was 
generally low for the counties having high percentage of winter 
wheat sown area. This means the most of the representative 
winter wheat production area in the plain had maintained to 
cultivate winter wheat in recent years, even though the national 
statistics data by FAO reported that the harvest area of wheat in 
the whole country reduced 26% from 1998 to 2003. 
The author also calculated the coefficient of variation of the 
percentage of winter wheat sown area by county for the period 
from 1998 to 2003. The results show that the variation was 
generally low in the representative production areas. High value 
of the coefficient could be appeared in the suburban areas. 
142 
  
  
  
Ü 
    
  
Percentage of winter wheat sown area 
by county in the northern part of 
Huang-Huai-Hai plain 
averaged for the period 
from 1998 to 2003 
  
  
  
  
0: 25503 oc sa 200 
[ mu um es A 
  
<-1.00 0.00-+025 
   
| +025- +050 Trend of winter wheat sown area 
es by county in the northern part of 
0.75 --050 £ | +050 -+0.75 ; . + 
Sa Huang-Huai-Hai plain 
*075-*100 expressed by the subtraction of 
025-00 M +1 00 < the averaged value of 1998 to 2000 
from the averaged value of 2001 to 2003 
(normalized by the mean value) 
à -100--075 
-0.50 - -0.25 
  
Figure 11. Trend of winter wheat sown area by county 
  
  
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