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AGRICULTURAL LAND CLASSIFICATION
ABERGELE EAST (2011), CONWY
ALC 001/2011
AGRICULTURAL LAND CLASSIFICATION SURVEY
ABERGELE EAST (2011), CONWY
CONTENTS
1.
Agricultural Land Classification
2.
References
Map 1
Agricultural Land Classification
AGRICULTURAL LAND CLASSIFICATION SURVEY
ABERGELE EAST (2011), CONWY
1.
AGRICULTURAL LAND CLASSIFICATION
Introduction
The original ALC map covering Wales was published in 1977 at a scale of 1:250 000
(one inch to four miles) and was marked ‘provisional’1. It shows the survey area to be
predominantly Grade 2 agricultural land. The purpose of the provisional map is to
provide broad-brush ALC, appropriate for strategic land use assessment. Additional
and more detailed survey work is needed where site specific ALC is required.
In response to a request from the Regional Planning Adviser, Welsh Assembly
Government (WAG), the majority of the area was surveyed in detail during August
and November 2007 (Map 1). In February 2011, an additional area was surveyed to
the north east of the 2007 area, and outlined in red on Map 1. The 2011 survey only
assessed the land outlined in red on Map 1. No additional survey work was carried
out, or ALC grade boundary changes made, within the 2007 survey area.
The purpose of both surveys was to assist in the agricultural evaluation of the site, to
provide further information on its ALC Grade and to subdivide any Grade 3 land
identified. The survey involved field sampling of soils at 100 metre intervals, together
with interpretation of aerial photographs, examination of published geological2,
climatic3 and soil data4,5,6.
For clarity, the 2007 and 2011 survey areas have been combined into one map and
report.
Land Use
The site covers approximately 60ha. At the time of the survey, the site was
predominantly under grassland.
a.
PHYSICAL FACTORS AFFECTING LAND QUALITY
i.
Climate
Average interpolated values for each climatic parameter as calculated
for this site are listed below:
Altitude
Average Annual Rainfall (AAR)
7 - 70 m
724 - 770 mm
Median Accumulated Temperature
above zero degrees C, January to June (AT0)
1423 - 1457 Day °C
Median Duration of Field Capacity Days (FCD)
Moisture Deficit (Winter Wheat)
Moisture Deficit (Potatoes)
171 - 180 Days
99 - 104 mm
88 - 95 mm
The favourable combination of the Average Annual Rainfall and
Accumulated Temperature values for this site meant it was not subject
to any significant limitations in terms of overall climate.
ii.
Site
The majority of the site was gently undulating, with gradients not
imposing any significant limitation to agriculture. However, some
areas, especially at the south of the site, contained gradients in excess
of 7 degrees. This resulted in moderately severe limitations relating to
gradient. A small enclosure to the west of Plas Isaf has severe
limitations to agriculture due to micro-relief.
iii.
Soils
A detailed survey of the site was carried out using a 120-centimetre
Dutch type hand auger. Samples were taken at approximately 100
metre intervals on a grid basis. Representative soil pits were dug to
supplement the auger boring information. Laboratory samples were
taken to confirm topsoil textures.
Soils on the site fell broadly into 2 types, both occurring across the
site:
Type 1 soils were typically composed of medium clay loam topsoils,
overlying medium clay loam and / or sandy clay loam / fine sandy clay
loam in the subsoil. Occasional subsoil horizons of heavy clay loam
were noted and some profiles contained clay in the lower subsoil.
Topsoil stone contents (>2cm diameter) were typically <5% by
volume. Subsoils were typically not significantly stony, though some
lower subsoil total stone contents (>2mm) were measured at 12% to
25% by volume.
Type 2 soils were typically composed of medium clay loam topsoils,
normally overlying medium clay loam in the upper subsoil with
reddish clay below. The reddish clay commonly occurred below c.40 –
60cm from the soil surface.
Stoniness was not a significant limiting factor in either topsoil or
subsoil.
iv.
Soil Wetness
Soils in Type 1 fell predominantly into Soil Wetness Classes (SWC) I
& II. Wetness Class II soils typically contained gleying within 40cm
from the soil surface. Soils in Type 2 fell predominantly into Soil
Wetness Class III & IV. Wetness Class was largely dependent on depth
to the slowly permeable reddish clay in the subsoil.
The topsoil textures present, in combination with the number of Field
Capacity Days (171 - 180) for this area, rendered the land subject to
slight, moderate, or moderately severe agricultural limitations related
to soil wetness and workability.
v.
Soil Droughtiness
The combination of soil textures and structures present in Soil Types 1
& 2, related to the Moisture Deficit values for this area, meant soils in
these types were typically not subject to significant limitations related
to droughtiness. Occasional profiles were subject to slight limitations
related to droughtiness.
b.
AGRICULTURAL LAND CLASSIFICATION
Under the MAFF Agricultural Land Classification system, land is graded according to
the degree to which certain physical characteristics - in particular climate, relief and
soil - impose long-term limitations on agricultural use. A full description of the
classification and of the criteria used in determining the gradings can be found in the
published MAFF Report7.
The areas of each Grade & Subgrade are delineated on Map 1, the reasons for grading
are outlined below:
Grade 2
Land has typically been mapped as ALC Grade 2 due to slight
agricultural limitations relating to soil wetness and workability.
Grade 3a
Land has been mapped as ALC Subgrade 3a due to moderate
agricultural limitations relating to soil wetness and workability.
Subgrade 3b Land has been mapped as ALC Subgrade 3b chiefly due to moderately
severe agricultural limitations relating to soil wetness and workability
or gradient.
Grade 4
Land has been mapped as ALC Grade 4 chiefly due to severe
agricultural limitations relating to microrelief.
Grades & Subgrades 1 and 5 did not occur within the survey area.
Areas of land in each Grade and Subgrade
ha
% Agricultural Land
% Total Land
Grade 2
Subgrade 3a
Subgrade 3b
Grade 4
9.03
31.90
12.89
0.77
17
58
24
1
15
53
21
1
Total Agricultural Land
54.59
100
90
Non Agricultural
Not surveyed
4.16
1.57
-
7
3
TOTAL SITE AREA
60.32
90
100
2.
REFERENCES
1
MAFF (1977): 1:250 000 Series Agricultural Land Classification: Wales.
2
Geological Survey of Great Britain (England and Wales) (1970): 1:63,360
Map Series, Sheet 95 (Rhyl) – Solid & Drift.
3
Meteorological Office (1989): Climatological Data for Agricultural Land
Classification. Met Office, Bracknell.
4
Soil Survey of England and Wales (1983): 1:250,000 Map Series, Sheet 2
(Soils of Wales), plus accompanying memoir.
5
Soil Survey of England and Wales (1960): Sheet 95 (Rhyl), 1:63,360, plus
accompanying memoir.
6
MAFF/Soil Survey of England and Wales (1984): Soil Texture, Leaflet 895.
7
MAFF (1988): Agricultural Land Classification of England and Wales:
Revised guidelines and criteria for grading the quality of agricultural land.
Ian Rugg
Sustainability and Environmental Evidence Division
Welsh Assembly Government
April 2011
Map 1
295000
Agricultural Land
Classification
ABERGELE EAST 2011
Grade
Agricultural Land
Quality
Excellent
0.00
3a
Good
31.90
4
Poor
1
2
377000
5
9.03
Very Good
3b
377000
Area (ha)
12.89
0.77
Moderate
Very Poor
0.00
Urban
0.00
Other Land Categories
W
Non Agricultural
4.16
0.00
Woodland
Agricultural Buildings 0.00
0.00
Open Water
Not Surveyed
1.57
Total Agricultural Land Area 54.59
60.32
Total Survey Area
Surveyed 2007
Surveyed 2011
160
80
0
160 Meters
This map is based upon the Ordnance Survey Boundary Line data
for The Welsh Assembly Government with the permission of
Ordnance Survey on behalf of The Controller of Her Majesty's
Stationery Office,© Crown Copyright. All rights reserved.
Unauthorised reproduction infringes Crown Copyright and may lead to
prosecution or civil proceedings. Licence Number 100017916.
Cartography by TSD GI Unit, DEPC, Aberystwyth.
© Crown Copyright 2007
295000
ALC Ref: 001/2011
Date: 06/04/2011