PROVINCIAL DIFFERENCE IN CUL TIVATED LAND AND GRAIN PROD UCTIVITY IN CHINA

Transcription

1 RESOURCES SCIENCE Vol. 25 No. 3 May ( ; ) : a : ; ; :F01411 ;F :A : (2003) PROVINCIAL DIFFERENCE IN CUL TIVATED LAND AND GRAIN PROD UCTIVITY IN CHINA LI Mao 1 ZHANG Hong2ye 2 (1. Information Center for the Ministry of Land and Resources Beijing China ; 2. Institute of Geographical Sciences and Natural Resources Research CAS Beijing China) Abstract :China s cultivated area has decreased steadily since In order to feed more and more people and to assure grain self2sufficiency in general we have to improve yield of farm crops per hectare and keep certain area under cultivation. This paper has revealed the provincial difference the quantity change of culti2 vated area and grain productivity change according to the data of long2series statistics of cultivated area mul2 tiple cropping index and grain yield during the past 50 years. This paper puts forward the conception of ratio of provincial s grain productivity to national average and has quantitative analysis of the comparatively weightiness of cultivated land s grain productivity in every province which is expected to provided scientific foundation for making2decision of protect cultivated land. There obvious provincial difference in cultivated area and grain productivity change since the founding of New China. The regional difference of cultivated area change indicates higher productivity cultivated area decreases while lower productivity cultivated area increas2 es. The cultivated area s grain productivity becomes small from south2east to north2west part in China. The highest cultivated area s grain productivity is located in the region of the middle and lower reaches of Yangtze River. Decrease of these provinces cultivated land will exert greater influence. The driving forces for the de2 crease of cultivated land s grain productivity in south2east are lower comparative benefit fewer cultivated land denser population and falling multiple cropping index. : ; : : ( : ) ; ( :CXIOG- AOO ) : (1970 )

2 Key words : Grain productivity of cultivated land ; Provincial difference ; Ratio of provincial grain productivity to national average Π [1 2 ] (LUCC) [3 ] [7 ] : K = U b - U a 1 U a T 100 % : K U a U b T [4 ] T K 3a : X i = Y i M i Y q M q 1 : X i Y i ( ) M i ; Y q [5 6 ] M q X i 1 X i X i X i

3 25 3 : ( 1) hm hm [8 11 ] 0108hm hm Fig. 1 Change of cultivated area and grain yield of China from 1949 to 1999 ( 1) [ % % ] kg hm kg hm - 2 ; 1Π3 2Π % % ; t t kg kg a ;

4 ( 1) ; 17a 6913 ; 10 4 hm Table 1 Provincial difference in cultivated land change ratio of change and ratio of provincial cultivated land s grain productivity to national average ( 10 4 hm 2 ) ( %) ( 10 4 hm 2 ) ( %) :

5 25 3 : 53 1hm 2 1hm 2 1) ; 4 ( 2) 3 : Fig. 2 Provincial difference in grain productivity of cultivated area kg hm kg hm : (1) : (2) : 8 200kg hm kg hm kg hm kg hm - 2 1) ( ) 1997

6 : (3) 2 300kg hm kg hm - 2 : 4 400kg hm kg hm - 2 (4) 3 Fig. 3 Provincial difference in the ratio of grain productivity of cultivated land to national average Fig. 4 Change rate of the provincial difference 1. 5 in the ratio of grain productivity of cultivated land to national average ( ) ( 1 4)

7 25 3 : 55 (3) a 230 % 187 % 184 % 178 % 259 % 243 % 159 % 153 % ; % % % % % 162 % 153 % 42 % % 178 % 101 % 118 % % : (1) hm : (2) 0135hm hm hm hm hm hm hm hm kg hm - 2 ;

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