Impact of urbanization on cultivated land in China: a model-based analysis in China Xiangzheng Deng November 6-8 ， 2014 2 nd International Conference Urban.

Impact of urbanization on cultivated land in China: a model-based

analysis in China

Xiangzheng Deng

November 6-8 ， 2014

2nd International ConferenceUrban Transitions and Transformations: Science, Synthesis and Policy

Urbanization is an inevitable development process Urbanization is a natural process companying with

the development of human society at a certain stage

People inhabitance

-urban area 2%

-population >50%

Labor shifts -Agricultural sector

Non-agricultural sector

Sourced from NetEase 2012

Sources: The times of India, 2008

Global urbanization rate

Urbanization in China Urban population– 1978-2013: risen from 18% to

54% Urbanization accelerated– since middle 1990s– 3/4 of the population would live

in cities by then end of 2050 Population in the urban areas – By 2020, over half of the people

will move into cities, according to a planning made by NDRC

– About 39 percent of the youngsters are employed in the urban, while only 27 percent of older workers work in small city or county

Urbanization in China: 1949-2009

Urbanization

Source: Urban China, 2010

Source: ChinaDaily, 2013

Views on the impacts of urbanization on agricultural land

Urbanization leading to cultivated land reduction and reduced land production directly through encroaching the land around urban core or the leapfrogged urban cluster

Urbanization playing an active role in conserving cultivated land by releasing the pressure from land occupations accompanying with the urbanization

Ideas on the urbanization models

Impacts of different models of urbanization on the changes of cultivated land

– Small town model– Lack of effective planning

– Consuming large areas of cultivated land

–City model– Infrastructure built

– As for the scales of land consumption : urban built area > rural built area

Research in Progress Failed to build a measurement indicator on urbanization

models by combining the built-up area in both urban and rural area and to do an integrated research

Need to fully control some factors with no matter positive or negative effects on urbanization to get a more robust estimation

Include different scales of cities with a diverse of urbanization speed into the analyses

“Major” question under answer

Does urbanization of big cities in China consuming more land compared with that of small towns as well as the expansion of villages?

How has the urbanization affected the land productivity and cultivated land area for the past three decades?

Is there any kinds of urbanization model saving land? What is the regional characteristics of land consumption

of urbanization?

Goals of PresentationExplored changes in China’s cultivated area and its

conversion to built-up area and other uses due to urbanization, industrialization and rural settlement expansion

Analyze the impacts of the urbanization models on the changes of land productivity

Explore the various effects of urbanization models on the changes of cultivated land over time and space

Answer questions from two aspects

The direct impacts of urbanization on the land productivity

Impact of urbanization on cultivated land changes in China

Estimate the Changes in Quantity and Quality of Cultivated Land: Methodology Identify the quantity of China’s land use change

– Detection models of Land Use Change(LUC),1-km area percentage data models

– Based on the prototype of the 1-km area percentage data model (1-km APDM), developed a set of programs to generate 1-km area percentage data according to map-algebra concepts

– i.e., the encroachment of urban land onto cultivated landMeasure the quality of cultivated land conversions– Agro-ecological Zones (AEZ) methodology– Manipulate data with GIS technologies– Use Agro-ecological zoning model (AEZ) with “other data” to

create a productivity index of cultivated land (essentially this index is a way that geographers measure the bio-productivity of land; in other words, it is a measure of the quality of land)

Estimate the Changes in Quantity and Quality of Cultivated Land: Database

Database:– Remote sensing data (RSD) on all of China (for land use)– Other data includes information on climate; soils; slope and

elevation; etc. (e.g., from China Meteorological Bureau) – 1x1 km GRID data

Temporal scale: 1988~2000; 2000~2008

Decoding the information on land use changes from Landsat TM/ETM digital imagines

False color composition

Geometric correction

1988/1990, 1999/2000,2005/2008Landsat TM digital image

Vector map of land use in 1988 、 2000 、 2005 、 2008

Mutual interpretatio

n

1988/1990,1999/2000,2005/2008Landsat TMregistered image

Land-use change map during the periods between 1988 to 2000 ； 2000-2008

1km vector mapArc/InfoOverlay

Land-use change map of predominant types during the period

between 1988-2000 and 2000-2008

Zoning map of land-use change during the

period between 1988-2000 and 2000-2008

Land use conversion maps during the period between 1988-2000 and

2000-2008

Characteristics and Measures on Land-use ChangeThe regional differentiation of land-use change rate

can be represented by the dynamic degree model of land-use, i.e.

%100)/1()/(

i

n

ijiji WtSSS

where, S is the land-use change rate, Si represents the total areas of i (land-use category) at the former stage while is the weight of areas proportion of i, represents the net change of area from i to j (land-use category) at the time scale of t. The basic unit to employ the dynamic degree model is 1km GRID, and the statistical result serves as basis to draw the land-use change and land-use conversion maps classified by land-use categories.

Changes in cultivated land

Panel a: 1988 to 2000

Panel b: 2000 to 2008

Conversions of Cultivated Land in China during 1988 to 2000 (Panel a) and 2000 to 2008 (Panel b)

In 1988-2000, 2.7 million hectares of new cultivated land was created. China’s farmers were cultivating 1.9% more land in 2000 than they were in 1988.

In 2000-2008, the cultivated land area of China actually lose considerable quantities of land, by 0.58 million hectares.


Panel a Panel bLand conversions from Cultivated Land to other uses, 1988-2000 (Panel a) and 2000-2008 (Panel b)

It should be noted that only in the case of Beijing, Shanghai and Zhejiang did the conversions exceed 5% in 1986-2000.

Apparently, the provinces that experienced the most conversions are Shanghai and Shandong in 2000- 2008.


Panel c Panel dLand conversions from other uses to cultivated Land, 1988-2000 (Panel c) and 2000-2008 (Panel d)

During 1988-2000, In northeast China, there were large tracts of forests that were converted to cultivated land; Some areas in Sichuan also were converted from forests to cultivated

During 2000-2008, there are less tracts of land that were converted to cultivated land

Changes in potential agricultural productivity and production due to land conversions

ProvinceTotal production potential in 1988

Increase DecreaseNet

changePercentage

changeProvince

Total production potential in 1988


changePercentage

changeBeijing 4120 23 837 -814 -19.75 Hubei 149000 721 2320 -1599 -1.07Tianjin 6220 13 204 -191 -3.06 Hunan 141000 333 1160 -827 -0.59Hebei 72600 396 1950 -1554 -2.14 Guangdong 90600 267 3460 -3193 -3.52Shanxi 34600 268 237 31 0.09 Guangxi 113000 1340 852 488 0.43Inner Mongolia

36100 4940 1630 3310 9.17 Hainan 16100 191 352 -161 -1

Liaoning 34000 1470 505 965 2.84 Chongqing 56300 87 396 -309 -0.55Jilin 31400 1970 441 1529 4.87 Sichuan 176000 417 1390 -973 -0.55Heilongjiang 53300 6210 524 5686 10.67 Guizhou 63300 613 99 514 0.81Shanghai 9170 0 1010 -1010 -11.01 Yunnan 67900 896 1090 -194 -0.29Jiangsu 114000 240 5000 -4760 -4.18 Tibet 1940 0 4 -3 -0.16Zhejiang 69100 313 3040 -2727 -3.95 Shaanxi 40800 434 379 55 0.13Anhui 137000 471 2110 -1639 -1.2 Gansu 32000 553 174 379 1.18Fujian 48100 543 772 -229 -0.48 Qinghai 2780 5.9 24 74 2.66Jiangxi 106000 537 1030 -493 -0.47 Ningxia 8540 1200 108 1092 12.79Shandong 97600 162 1430 -1268 -1.3 Xinjiang 28700 2750 883 1867 6.51Henan 111000 1500 1340 160 0.14 Taiwan 13500 13 76 -63 -0.46Total 1965770 28971 34826 -5855 -0.3

Change of total production potential associated with changes in cultivated land by provinces for 1988-2000, measured in billion Kcal and percentage change (%).

The average potential agricultural productivity fell by 2.2% during 1988-2000, and the total production potential fell by 5.9 trillion Kcal, or by only 0.3%


ProvinceTotal production potential in 2000


changePercentage

changeProvince

Total production potential in 2000


changePercentage

changeBeijing 3306 3.4 280.8 -277.3 -8.39 Hubei 147401 31.9 2371.1 -2339.3 -1.59Tianjin 6029 1.9 139.7 -137.8 -2.29 Hunan 140173 2 1215.1 -1213 -0.87

Hebei 71046 122.6 914.9 -792.3 -1.12 Guangdong 87407 37.5 2164.7 -2127.2 -2.43

Shanxi 34631 1.4 798.4 -797 -2.3 Guangxi 113488 31.5 787.1 -755.7 -0.67Inner Mongolia

39410 460.6 118.8 341.7 0.87 Hainan 15939 23 131.1 -108.1 -0.68

Liaoning 34965 40.6 221.4 -180.9 -0.52 Chongqing 55991 23.7 2111.1 -2087.3 -3.73

Jilin 32929 71.9 155.8 -83.9 -0.25 Sichuan 175027 68.9 1553 -1484.1 -0.85Heilongjiang 58986 1380.2 802.8 577.4 0.98 Guizhou 63814 27.6 1103.9 -1076.3 -1.69Shanghai 8160 0 1993.9 -1993.9 -24.43 Yunnan 67706 94.4 981.6 -887.2 -1.31Jiangsu 109240 28 8319.2 -8291.2 -7.59 Tibet 1937 0 1.3 -1.3 -0.07Zhejiang 66373 15.7 1673.6 -1657.9 -2.5 Shaanxi 40855 170.1 550.1 -380.1 -0.93Anhui 135361 535.9 3594.5 -3058.6 -2.26 Gansu 32379 316.6 408.1 -91.5 -0.28Fujian 47871 18 1220.3 -1202.3 -2.51 Qinghai 2854 4.6 21.6 -17 -0.59Jiangxi 105507 633.2 1060.9 -427.6 -0.41 Ningxia 9632 249.4 215.2 34.2 0.35Shandong 96332 166.4 2967 -2800.6 -2.91 Xinjiang 30567 1781.6 46.1 1735.6 5.68Henan 111160 99.3 1243.1 -1143.8 -1.03 Taiwan 13437 6.9 181.8 -174.9 -1.3Total 1959913 6449 39348 -32899 -1.68

Change of total production potential associated with changes in cultivated land by provinces for 2000-2008, measured in billion Kcal and percentage change (%)

The average potential agricultural productivity fell by 1.3% during 2000-2008, and the total production potential fell by 32.9 trillion Kcal, or by around 1.7%


Panel a: 1988 to 2000 Panel b: 2000 to 2008Changes in total production potential (measured in million kcal) associated with changes in cultivated area in China during 1988 to 2000 (Panel a) and during 2000 to 2008 (Panel b).

During 1988-2000, the quantity of cultivated land rose by 1.9%. The average potential productivity of land fell by only 2.2%

During this period, the quantity of cultivated land deceased 0.58 million hectares and the average potential productivity of land fell by 1.7%

SummaryIndeed, net cultivated land actually increased during the

study period, 1986 to 2000. Our decomposition of cultivated land changes show that nearly half of lost cultivated land was due to cultivated land being converted to grassland (30%) and forest (17%). Of the remaining, nearly 40% was due to the shift to built-up area.

There also was a considerable amount of newly cultivated land created, some shifting into cultivation from grassland and other from forestry areas

Although newly cultivated area rose, average potential agricultural productivity actually fell

Answer questions from two aspects

The direct impacts of urbanization on the land productivity

Impact of urbanization on cultivated land changes in China

Three kinds of models of urbanization Indicator measured by remote sense digital images

– Exploring the sizes of “villages”, “towns”, “cities” by a sampled survey

– Raw data, Landsat TM/ETM, CBERS– Four time period: late 1980s, mid-1990s, late 1990s, mid-2010s (Liu et

al, 2002; Liu et al, 2009 )

Aggregated based on neighborhood of the residential polygons with the reference for the year 2005– 18 counties/cities within nine provinces sampled and re-visited which

are located in the eastern, central and western regions of China– The threshold to identifying the three levels of residential areas

• Villages, equal or less then one square kilometer• Towns, one to five square kilometers• Cities, bigger then five kilometers

Three kinds of urbanization models

City Model

Urbanization of Beijing

Village Model

Town Model

Urbanization of Fangshan

Urbanization of Yancun

Beijing Municipal Institute of City Planning & Design, 2007

Controlling and influencing factorsGeophysical variables

– slope, percent of plain area, elevation, distances of counties’ (cities’) seats to the capital cities and nearest port cities, and so on.• DEM data and topographic map• Thematic maps on residence and road network

– precipitation and average temperature data• China Meteorological Administration during 1950-2000

Economic variables– economic data and population of counties (cities)

• National and provincial bureaus of statistics, various years– FDI– development zones

Policy variables• Household registration policy• County updated to city

Descriptive statistics of the main variables

Variables Unit

1996 2000 2008

meanstd.

deviationmean

std. deviation

meanstd.

deviation

cultivated land area hectare 69277 66091 68250 67952 66062 68643

cultivated land area (1989) hectare 66630 61212 66630 61212 - -

cultivated land area (1995) hectare - - 69277 66091 69277 66091

built-up area：

village-model land ratio percentage 67.16% 22.01% 65.71% 21.78% 60.54% 22.36%

town-model land ratio percentage 12.00% 11.57% 12.66% 11.87% 15.96% 12.97%

city-model land ratio percentage 20.84% 20.84% 21.63% 22.21% 23.50% 23.50%

policy factors：

non-agricultural population registered (t-1)

percentage 23.76% 20.38% 25.19% 20.43% 45.51% 34.83%

County upgraded to city (yes =1) 0.24 0.43 0.26 0.44 0.29 0.45

foreign direct investment per capita yuan per capita 2212 2314 3911 3894 5200 5019

development zone (exist =1) 0.36 0.48 0.37 0.48 0.41 0.5

Descriptive statistics of the main variables (continued)

variable unit

1996 2000 2005

meanstd.

deviationmean

std. deviation

meanstd.

deviation

Economic factors:

GDP(t-1) million yuan* 4331.98 9603 6567.68 16370 9467 18823

Agriculture GDP(t-1) million yuan 825.86 591.79 986.72 696.27 1338.68 962.11

Industry GDP(t-1) million yuan 2004.27 4980.47 3043.47 8167.19 4324.11 11028

Service Industry GDP(t-1) million yuan 1501.85 4647.55 2537.49 8225.31 3804.21 13123

population(t-1) Person 631933 607333 653616 628337 731665 821621

Environmental factors:

slope Degree 2 2 2 2 2 2

distance to the nearest port Kilometer 467 342 467 342 467 342

distance to the capital city Kilometer 164 96 164 96 164 96

DEM Meter 233 255 233 255 233 255

plain area proportion percentage 0.53 0.38 0.53 0.38 0.53 0.38

annual precipitation mm 1016 510 1016 510 1016 510

average temperature ℃ 13 6 13 6 13 6

Observations 870 870 879

Equations

Cultivated land area = f (ratio of urbanization models, social and economic variables, geophysical variables, other control factors, random error term)

Build-up areas of urbanization models = f (social and economic variables, geophysical variables, other control factors, random error term)

Estimation results, for the eastern region, the decision factors of urbanization models and cultivated land, 1995-2000, (Pooled OLS)

Explanatory variables"Small-town"

model proportion"City" model

proportionCultivated land

area(3SLS)

Explained variables in 19891.018

(199.39)***

"Small-town" model proportion0.084 0.117

(77.85)*** (4.25)***

"City" model proportion0.853 0.036

(64.85)*** (1.80)*Policy instrumental variables

Non-agri population registered (t-1)-0.025 0.087

(2.36)** (5.96)***

County updating to city (yes=1)0.004 0.013-1.22 (3.02)***

Foreign direct investment per capita

0.001 -0.003-0.82 (1.30)

Development zone (exist=1)-0.01 0.011

(2.83)*** (2.50)**

Explanatory variablesTown-area land

expansionCity-area land

expansioncultivated land

area

Socio-economic factors

Agriculture GDP(t-1)-0.006 0.002 0.021

(1.98)** (0.42) (3.25)***

Industry GDP(t-1)0.002 0.005 -0.009-0.65 (1.45) (1.66)*

Service Industry GDP(t-1)0.003 0.014 -0.025-0.87 (3.00)*** (3.66)***

Population(t-1)-0.003 -0.022 -0.006(-0.71) (4.85)*** (0.80)

Physiographic factor

Slope-0.002 -0.002 -0.001

(2.15)** (1.88)* (0.30)

Distance to the nearest port0.001 -0.004 0.007(-0.87) (2.70)*** (2.83)***

Distance to the capital city-0.000 -0.007 0.02(0.02) (2.96)*** (5.48)***

DEM-0.000 0.002 -0.000(0.33) (2.66)*** (0.06)

Plain area proportion-0.001 -0.012 -0.043(0.22) (1.53) (3.44)***

Average precipitation-0.007 -0.057 0.041(1.17) (7.97)*** (3.89)***

Average temperature0.000 0.005 -0.004(1.06) (9.34)*** (4.58)***

R2 0.78 0.91 0.99Observations 1738 1738 1738

Estimation results for the eastern region, the decision factors of urbanization model and cultivated land, 2000-2008, (Pooled OLS)

Explanatory variables"Small-town"

model proportion"City" model

proportionCultivated land

area(3SLS)

Explained variables in 19891.023

(128.84)***

"Small-town" model proportion0.826 -0.146

(54.23)*** (2.92)***

"City" model proportion0.793 -0.067

(64.47)*** (2.01)*Policy instrumental variables

Non-agri population registered (t-1)0.021 0.037

(2.10)* (3.51)***

County updating to city (yes=1)-0.005 -0.001 (-0.95) (-0.13)

Foreign direct investment per capita

0.003 -0.008 (1.14) (-2.88)***

Development zone (exist=1)0.000 -0.005 (0.03) (-0.95)

Explanatory variablesTown-area land

expansionCity-area land

expansioncultivated land

area

Socio-economic factors

Agriculture GDP(t-1)0.015 -0.018 0.014

(3.59)*** (-4.24)*** (1.38)

Industry GDP(t-1)0.004 0.012 -0.003(1.04) (2.75)*** (0.34)

Service Industry GDP(t-1)-0.015 0.022 -0.037

(-2.69)*** (3.82)*** (3.25)***

Population(t-1)-0.012 -0.007 0.038

(-2.07)* (-1.25) (3.06)***Physiographic factor

Slope0.004 -0.001 0.005

(3.03)*** (-0.46) (1.38)

Distance to the nearest port-0.011 -0.001 0.002

(-3.49)*** (-0.36) (0.39)

Distance to the capital city-0.000 0.004 -0.003(-0.13) (1.28) (-0.41)

DEM-0.001 -0.000 -0.008(0.89) (-0.30) (-3.42)***

Plain area proportion0.017 0.001 0.009(1.77) (0.13) (0.43)

Average precipitation0.008 -0.012 -0.091(1.01) (-1.47)*** (-5.42)***

Average temperature-0.000 0.004 0.000(-0.60) (5.37)*** (0.06)

R2 0.56 0.85 0.97Observations 1738 1738 1738

The estimation result of urbanization models In 1995-2000, the household registration policy has significant

different impacts on different urbanization models ， the influence coefficient is -0.025 ； However, the household registration policy has significant positive influence on “City” model ， the coefficient is 0.087

In 1995-2000, the implementation of county to city (or district) has a negative effect on “Small-town” model, but has a significant positive effect on “City” model, the influence coefficient of estimation is 0.013, and statistical tests of coefficient are significant at the level of 1%. However, in 2000-2008, the estimation results show that the development of county to city (district) has an effect on “Small-town” model and “City” model

The estimation results of urbanization models

Further, In 1995-2000, the effects of the foreign direct investment on both “Small-town” model and “City” model are not significant, but in 2000-2008, the effect was significant in “City” model, the influence coefficient is 0.008

The regional development policy has a significant negative effect on “Small town” model, but has a positive effect on “City” model, this is because the development zones are generally set up around the town and consequently promote its expansion

The estimation results of the cultivated land modelIn 1995-2000, the cultivated land which was used in the

small town model and city model is more economical than in village model, and the less percent of occupied the cultivated land is 0.12% and 0.04%, respectively

In 2000-2008, the cultivated land which was more used in the small town model and city model than in village model, and the urbanization level increases every one percent will lead to the cultivated land which was occupied by construction land increase more than 0.15% and 0.07%.

The estimation results of the cultivated land model Natural factors are also the important factors to explain regional

differences of cultivated land. In the seven natural factors which are considered, there are five variables are reached 1% significant level, they are the nearest distance to the province capital, the nearest distance to the port, the ratio of plain area, precipitation and average temperature

In 2000-2008, when the agricultural GDP growth by 1%, the cultivated land will increase (or save) about 0.02%. This is because agriculture development needs a large number of cultivated land, the more agriculture develop, the more cultivated land used for farming

In 2000-2008, as industrial GDP or service industry GDP growth by 1%, the cultivated land will reduce about 0.003% and 0.037%, respectively

Decomposition analysis of cultivated land change;(1996-2000)

VariableEstimated parameter

[1]Variation （ % ） [2]

Influence [3]=[1]×[2]

Rate of contribution（ % ） [4]=[3]/（ -1.48 ） *100

Urbanization (construction land area ratio)

“Village”(Rural residential)

Town 0.117 0.66 0.08 -5City 0.036 0.79 0.03 -2Agriculture GDP* （ t-1 ） 0.021 18.08 0.37 -25Industry GDP* （ t-1 ） -0.009 40.45 -0.35 24

Service industry GDP* （ t-1 ） -0.025 50.07 -1.27 86

Population * （ t-1 ） -0.006 3.12 -0.02 1Other variables -0.32 21

Change of cultivated land area （ % ） -1.48 100

Note: Italicized data represents that the coefficient based on the decomposition analysis is not significant

Decomposition analysis of cultivated land change;(2000-2008)

VariableEstimated parameter

[1]

Variation （ % ）[2]

Influence [3]=[1]×[2]

Rate of contribution（ % ） [4]=[3]/（ -1.48 ） *100

Urbanization (construction land area ratio)

“Village”(Rural residential)

Town -0.146 3.33 -0.486 23.2City -0.067 1.87 -0.125 6.0Agriculture GDP* （ t-1 ） 0.014 35.67 0.499 -23.8Industry GDP* （ t-1 ） -0.003 42.08 -0.126 6.0

Service industry GDP* （ t-1 ） -0.037 49.92 -1.847 88

Population * （ t-1 ） 0.038 11.94 0.454 -21.6Other variables 1.150 77.7

Change of cultivated land area （ % ） -2.1 100

Note: Italicized data represents that the coefficient based on the decomposition analysis is not significant

SummaryAssuming that other factors remain constant, in 1995-

2000 of eastern region, the urbanization alleviates the loss of cultivated land by 7%, compared with the expansion of villages or the development of small towns

In the period of 2000-2008, the rapid urbanization resulted in the cultivated land loss by 29.2%. The policies designed to protect cultivated land by encouraging people move to small towns may actually accelerate the occupation of cultivated land

Concluding remarksWe saw net cultivated land actually increased during the

study period 1986 to 2000. Although newly cultivated area rose, average potential agricultural productivity actually fell.

Despite this, when examined in the aggregate for the entire period, the effect on total agricultural potential output was negligible.

Economic growth is the major determinant of any changes in cultivated land use

social, economic, and geophysical factors, such as industrial structure, population growth…played an important role in influencing urbanization

Although urbanization has an effect on the changes of cultivated land, its effect is marginal

Thank you for your attention

Xiangzheng Deng

November 6-8 ， 2014

2nd International ConferenceUrban Transitions and Transformations: Science, Synthesis and Policy