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Urban encroachment and loss of prime agricultural land

F.M.Kelleher

Centre for Farming Systems Research, University of Western Sydney, Hawkesbury Campus, NSW.

ABSTRACT

Area and distribution of land by DLWC Land Capability Class (LC) for three NSW local government areas (LGAs) (Hawkesbury, Wollondilly and Mudgee) were determined with MapInfo GIS software. ‘Prime’ agricultural land (LC 1-3) area was small in both Hawkesbury and Wollondilly, while Mudgee had a greater proportion and total area of each. Subdivision of prime land in Hawkesbury and Wollondilly was not correlated with LC, but reflected rapid urban development on the western fringe of Sydney. LC 1-3 land in Mudgee was less intensively subdivided, reflecting its agricultural value and shire action to preserve them. Potential exists for substantial future land losses from agriculture in each LGA, as large areas currently in agricultural use have been extensively subdivided into smaller lots over a long period. The major agricultural industries in Hawkesbury and Wollondilly are much less dependent on land quality than those in Mudgee and as a result, are less threatened by future threats to prime land.

KEY WORDS

Subdivision, urban encroachment, land capability, cadastre, MapInfo, land loss, prime land.

INTRODUCTION

Land loss from Agriculture has been the focus of considerable research in the US and UK, but there has been little discussion or research on it in Australia (1). Loss of agricultural land does not necessarily equate to loss of agricultural industry (1,2,4), as land productivity is irrelevant in intensive industries such as poultry and mushrooms. Concern has been expressed at the loss of prime land in NSW (6) and has led to legislation in Qld and Vic to prevent its permanent loss through subdivision and urban development (2,4), while other states are considering similar action. Residential subdivision and hobby farm development are often blamed for loss of both prime land and agricultural industry, but the true extent of such loss in NSW is questionable (1). They may in fact foster retention of otherwise non-viable agriculture in a region (1), but carry greater risk of land and environmental degradation (3,7). Changes to agricultural land use with urban and residential encroachment often result in the intensification of agricultural industry and new, financially viable alternative forms of agriculture. Limiting subdivision of agricultural land could thus inhibit the emergence of new forms of agriculture that might contribute significantly to regional socio-economic development (7). Intensive industries are less dependent on land quality (4), but often create undesirable impacts and conflict when co-located with rural residences. Hence the case for preservation of prime land in peri-urban areas solely for its traditional agricultural value cannot be sustained (4). Data on the extent of loss of both prime land and agricultural industry in peri-urban areas is limited (6), but both have been major issues for local government (5). This paper reports research showing that the major threat to agricultural industry in western Sydney is not the subdivision and loss of prime land, but rather the pressures of urban or rural residential encroachment on its major industries poultry and mushrooms, for which land quality is irrelevant. In contrast, agriculture in Mudgee is dominated by traditional, prime land dependent industries, on which land loss impacts would be substantial. Agricultural land appears to be valued largely for its amenity value in western Sydney (5) and its protection appears to be more realistically justified on these grounds.

METHODS

Distribution and extent of agricultural land use in 1996 was determined for each LGA from Landsat TM imagery, with extensive ground survey. Thematic land use maps were then developed in MapInfo, a GIS (Geographic Information System). Farm gate production value was estimated for all industries using conversion factors developed from industry criteria and production returns (4). Digitised Land Capability data for the three LGAs from NSW Department of Land and Water Conservation (DLWC) was separated in MapInfo into discrete layers for each LC, enabling distribution and area of each LC to be determined. Subdivision of prime (LC 1-3) land was determined by overlaying cadastre for each LGA on the corresponding composite map of these classes in MapInfo. For each LC, total number and area of individual allotments was then categorised into lot sizes of <1, 1-4, 4-12 and >12 ha within each agricultural land use category. This enabled the extent and intensity of subdivision of each LC to be determined separately for land under each agricultural use. Cadastre was then separated in MapInfo into layers for individual decades of Deposited Plan (DP) registration, using NSW Land Titles Office deposition codes. Each was then overlaid onto composite maps of LC 1 to 3, to determine whether subdivision showed any time trends or concentration on prime land classes.

RESULTS AND DISCUSSION

Value of Agricultural Production

Area and estimated value of agricultural output of the three LGAs for 1996 are shown in Table 1. Agriculture in the two western Sydney LGAs is dominated by the intensive, non-land dependent, mushroom and poultry industries, both of which are seriously threatened by urban encroachment (4). The major land dependent industries turf, market gardening and some dairying are largely located on LC 1 and 2 land on the Hawkesbury floodplain. Orcharding in both is located on higher, less productive but flood-free LC 3 and 4 land. In contrast, agricultural industry in Mudgee is largely land dependent and, except for vines, less intensive, with the major industries, grazing and vines, located on Classes 1 to 4 land. Mudgee, the largest of the LGAs, has the greatest proportional land area devoted to agriculture (Table1) but the lowest value of agricultural production.

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Table 1 . Estimated area and farm gate value of agricultural industries in Hawkesbury, Mudgee and Wollondilly LGAs, December 1996 (4).

Local Government Area

Hawkesbury

Wollondilly

Mudgee

 

Area (ha)

Value ($)

Area (ha)

Value ($)

Area (ha)

Value ($)

Land Dependent (LD) Agricultural Industries

Turf

1,571

31,640,000

209

4,210,500

5

125,000

Orchards

1,529

50,327,000

956

31,000,000

363

9,600,000

Market Gardens

1,634

16,240,000

1,036

9,600,000

38

400,000

Dairying

1,236

10,676,000

5,698

7,307,000

n.a.

200,000

Vines

71

390,500

n.a.

n.a.

2,906

27,000,000

Grain Crops *, **

neg.

neg.

neg.

neg.

75,356

2,000,000

Lucerne

179

480,000

n.a.

n.a.

6,315

4,100,000

Forestry

184

100,000

n.a.

n.a.

n.a.

n.a.

Berries/Nuts

157

1,500,000

n.a.

n.a.

n.a.

n.a.

Grazing

22,445

3,330,615

38,179

5,692,000

256,962

19,300,000

Horses #

3,961

no estimate

3,586

no estimate

5,000

no estimate

Other ##

226

150,000

138

250,000

n.a.

24,000

Total LD

33,193

114,834,115

49,802

58,059,500

346,945

62,749,000

Non-Land Dependent (NLD) Agricultural Industries

Mushrooms

30

66,000,000

20

3,000,000

   

Poultry

250

30,000,000

1,244

300,000,000

   

Pigs

       

n.a.

400,000

Total NLD

280

96,000,000

1,264

303,000,000

n.a.

400,000

Total All Agriculture

33,473

210,834,115

51,066

361,059,500

346,945

63,149,000

Total LGA Area (‘000 ha)

279

 

256

 

672

 

% Agricultural Land

11.8

 

21.6

 

50.3

 

*included in Market Gardens for Hawkesbury and Wollondilly. **Mixed grazing and cropland for Mudgee. #grazing area shared with cattle, value not determined. ##mainly exotic animals (deer, alpacas).

Land capability

Limited areas of prime arable land (LC1 to 3) occurred in both Hawkesbury and Wollondilly, with each LGA dominated by LC 7 and 8 land, National Parks, or protected water catchment areas, all of which excluded commercial agriculture. Mudgee had both a higher proportion and greater total area of land in these prime (1-3) classes (Table 2).

Subdivision by Capability Class

The great majority of LC 1 to 3 land in Hawkesbury has been extensively subdivided (Table 3) over time, but the flood-prone location of LC 1 land has limited it to relatively large (>12 ha) allotments and had little impact on its availability for agriculture. In contrast, intensity of subdivision (based on lot size) on

LC 2 and 3 land is greater, and imposes a potential threat to its continuing availability for agriculture (4).

Table 2. Area and percentage of total LGA area by DLWC Land Capability Classes for Hawkesbury, Mudgee and Wollondilly LGAs, December 1996. (4).

LGA

Hawkesbury

Wollondilly

Mudgee

Capability Class

Area (ha.)

% of LGA

Area (ha.)

% of LGA

Area (ha.)

% of LGA

1

3,491

1.25

0

0

3,058

0.46

2

6,088

2.18

3,540

1.38

25,497

3.79

3

10,471

3.75

5,248

2.05

56,329

8.38

4

18,444

6.61

18,552

7.26

148,997

22.17

5

1,262

0.45

3,534

1.37

78,089

11.62

6

8,015

2.87

10,454

4.09

119,328

17.76

7/8

212,608

76.13

50,497

19.77

117,920

17.55

Other *

18,883

6.76

163,842

64.08

122,724

18.26

Total

279,262

100.00

255,667

100.00

671,944

100.00

*Water, National Parks, urban, mining, State Forest areas not included in Capability Classes

Subdivision of the limited area of LC 2 and 3 land in Wollondilly is substantially less than in Hawkesbury, reflecting past planning policies and its use for medium scale dairy farming, now considered under threat (4). Hawkesbury and Wollondilly have large numbers of allotments of < 4 ha, under a range of land uses (Table 4). In Mudgee, high proportions of LC 1 to 3 land had been subdivided, but less intensively than in the western Sydney LGAs, and it was not seen to be under threat of loss from agriculture. The main population centres, Mudgee and Gulgong, are on LC 3 land, with LC 2 land adjoining. LC 1 land on the Cudgegong floodplain adjacent to Mudgee township is under mounting pressure for subdivision and development (4). Two waves of subdivision, pre-1920 and post-1960, were evident in each, reflecting early settlement in Hawkesbury and Wollondilly and, particularly, the gold rush period in Mudgee. Most subdivision occurred in the post-1960 wave in each. Patterns of subdivision in Hawkesbury indicated that land quality was largely irrelevant as a development constraint, as all LC 1 to 3 classes show the same trends over the entire period, suggesting other factors such as infrastructure and services dominated decision making on land development.

Table 3. Subdivision (total area [ha] per decade) of prime agricultural land by decade of plan deposition for Hawkesbury, Wollondilly and Mudgee LGAs (4).

LGA

Hawkesbury

Wollondilly

Mudgee

 

DLWC Land Capability Class

 

1

2

3

1

2

3

1

2

3

Period

                 

Pre 1920

110

204

381

-

43

283

182

556

967

1921-30

36

29

104

-

0

25

201

103

518

1931-40

4

1

90

-

59

 

2

37

37

1941-50

144

21

96

-

20

52

9

87

3

1951-60

116

52

373

-

45

33

58

471

545

1961-70

432

679

1,852

-

166

478

105

992

869

1971-80

616

1,030

1,833

-

311

442

239

2,612

3,124

1981-90

608

1,500

1,333

-

132

518

623

2,189

3,905

Post 1991

25

149

268

-

40

64

146

249

387

Total

2,092

3,664

6,332

-

817

1,893

1,565

7,296

10,355

Other**

1,175

1,788

2,764

-

346

924

1,109

15,316

37,865

Total Area

3,267

5,453

9,096

n.a.

1,163

2,817

2,674

22,612

48,220

Total Class Area

3,491

6,088

10,471

0

3,540

5,248

3,058

25,497

56,329

% Subdivided

94

90

87

n.a.

33

54

87

89

86

** includes all non-private land use- roads, easements etc

Intensity of subdivision on agricultural land

Land subdivision by lot size on all agricultural land is summarised in table 4 for all land uses, which shows that extensive subdivision of agricultural land has already occurred and, depending on zoning, rural residential or even urban development could occur without further subdivision in all LGAs. Subdivision of land categorised as bushland, not used for agriculture, is extensive.

Table 4. Number of registered lots by size and land use for agricultural land in the three LGAs (4).

LGA

Hawkesbury

Wollondilly

Mudgee

Lot Size (ha)

<1

1-4

4-12

>12

<1

1-4

4-12

>12

<1

1-4

4-12

>12

Land Dependent (LD)

Turf

38

56

103

31

   

3

9

   

1

 

Orcharding

13

44

73

40

10

56

41

27

   

16

3

Market gardening

41

104

107

40

6

40

47

26

   

1

1

Dairying

25

65

57

32

18

18

19

73

       

Vines

2

3

5

1

       

4

13

46

82

Grain Crops

               

211

313

535

1661

Lucerne

0

8

11

2

       

10

23

61

125

Grazing

319

778

780

409

246

468

380

653

1633

1201

2003

4481

Horses

124

358

170

83

8

37

97

90

1

1

6

22

Other

12

27

11

12

5

8

5

8

   

1

3

Total LD

575

1449

1323

659

293

628

592

886

1859

1551

2670

6379

Non Land Dependent

Mushrooms

1

1

2

                 

Poultry

3

6

5

9

6

54

27

26

       

Total NLD

4

7

7

9

6

54

27

26

0

0

0

0

Bushland

423

232

700

630

662

480

443

665

578

342

599

1676

Rural Residential

1,962

726

489

70

1061

1441

482

56

163

122

450

105

CONCLUSIONS

Agriculture in Hawkesbury and Wollondilly is moving towards industries that are less, rather than more, dependent on prime quality land. LC 1 and 2 land in Hawkesbury has already been extensively subdivided, but its inherent flood liability will prevent urban encroachment and ensure its short term retention in agriculture. Wollondilly retains much of its Class 2 and 3 land in agricultural use, but future industry viability and subdivision pressures suggest its eventual loss to agriculture, notwithstanding Wollondilly Shire Council’s specific planning policies to retain it. The case for prime land retention for agriculture in these LGAs is undermined by the economic domination of non-land dependent industries and the poor viability of land dependent industries (4). Economic pressures to subdivide land may in fact spawn new, high value agricultural industries, but these can thrive only when local government planning precludes barriers to their viable operation. Future, intensified, industries are likely to be even less dependent on land quality and the case for protection of prime land is likely to be stronger when based on its community amenity, rather than its agricultural, value. Rural residential development may do more to retain traditional industries than large scale retention of financially marginal operations (4). In contrast, agriculture in Mudgee seems likely to remain based on traditional industries which require quality land and the threats of prime land loss to the regional agricultural economy appear much more serious (5).

Acknowledgments

Financial support for this research by RIRDC is gratefully acknowledged

REFERENCES

1. Bowie, I.J.S. 1993. Urban Policy and Research 11 : 217-229.

2. Houston, P. 1994. Proceedings Agriculture and Rural Industries on the Fringe Conference, Melbourne, p 103.

3. Jones, E., Jones, P.R., Horsfall, W. and O'Dwyer, P. 1992. Australian Planner 30 : 4-44.

4. Kelleher, F.M., Chant, J.J. and Johnson, N.L. 1998a. RIRDC, Canberra, publication 98/15, 234 pp.

5. Kelleher, F.M., Chant, J.J and Johnson, N.L. 1998b. Proceedings 9th Australian Agronomy Conference, Wagga Wagga, p 617.

6. Kennedy, A. 1993. Country Towns and Rural Areas Planning and Development Conference : The Agenda for the 90's , Bendigo, p 33.

7. Musgrave, W.F. 1986. Rev. Mark. Agric. Econ. 54 : 70-74.

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