AGRICULTURAL USE & QUALITY OF LAND NEAR MINDALE HOUSE PRESTATYN Report 762/1 11 th April, 2012
AGRICULTURAL USE & QUALITY OF LAND NEAR MINDALE HOUSE PRESTATYN F W Heaven, BSc, MISoilSci Report 762/1 Ltd Lockington Hall, Lockington, Derby DE74 2RH 11 th April, 2012
SUMMARY An agricultural land classification survey has been carried out of 4.2 ha of arable land near Mindale House, Ty Newydd Road/FFordd Hendre, Prestatyn. The land is dominated by heavy textured, slowly permeable soils developed in reddish till or clayey alluvium. Agricultural land quality is governed by the degree of winter wetness in the soils, placing about three quarters of the land in sub-grade 3b and the rest in sub-grade 3a. 1
1.0 Introduction 1.1 This report provides information on the soils and agricultural quality and use of 4 ha of land to the north of Mindale House, Ty Newdydd Road, FFordd Hendre, Prestatyn. The land is being considered for development. The report is based on a soil and agricultural desk study and a survey of the land in April 2012. SITE ENVIRONMENT AND AGRICULTURAL USE 1.2 The site comprises agricultural fields that lie to the north-west of Mindale House and the urban development of Meliden. The application boundary in the north east and west is marked by field boundaries. The land slopes down from 25 m aod in the south east to around 18 m aod in the north-west. 1.3 The land is in grass used for the pasturage of horses. One field has been worked to provide a dressage area for horses with a sand cover over a membrane. 1.4 Historically, the land has been used for market gardening, but with limited success. PUBLISHED INFORMATION 1.5 BGS 1:50,000 geological mapping shows that the land is underlain by Pennine Coal Measures, covered by Devensian Till on the upper slopes, and with Flandrian alluvium in the valley floor. 1.6 The National Soil Map 1 at 1:25,000 scale shows soils of the Salop association, comprising slowly permeable seasonally waterlogged fine loamy over clayey soils associated with some more freely-draining types. 1.7 The provisional Agricultural Land Classification (ALC) map series published at one inch to the mile published in 1971 shows the land as of Grade 2 quality. 1 Rudeforth, C. C, et al (1984): Soils and their Use inwales. Soil Survey of England and Wales Bulletin No 11 2
2.0 Soils 2.1 The Defra Soil Strategy 2 points out that soils deliver a range of vital functions for human activities including production of food and fibre, support for ecosystems and habitats, and environmental services that play a vital role in the global carbon cycle, stabilising and degrading contaminants and providing clean water. One of the strategy s objectives is to ensure that soil functions (soil ecosystem services) are fully valued in the planning process. 2.2 A detailed soil resource and agricultural quality survey was carried out in early April 2012. It was based on observations at intersects of a 50 m grid, giving a sampling density of more than two observations per hectare. During the survey soils were examined by a combination of pits and augerings to a maximum depth of 1.1 m. A log of the sampling points and a map (Map 2) showing their location is in an appendix to this report. 2.3 The survey shows that the fields mainly have clay lower subsoil overlain by a variable thickness of loamy upper subsoil. The topsoil is heavy or medium clay loam. Heavy soils 2.4 The topsoil is typically a 25-30 cm-thick heavy or medium clay loam over heavy clay loam upper subsoil with mottle colours indicting seasonal wetness. On the sloping land in the east the lower subsoils are reddish brown and grey mottled clays with occasional stony and sandy pockets. On the flat land of the valley floor the lower subsoils are formed in clayey alluvium. 2.5 A typical profile from near observation 8 (Map 2) is described below: 0-28 cm Dark brown (7.5YR 3/2) heavy clay loam; a few small subangular stones; moderately developed medium subangular blocky structure; friable consistency; 5% fine and medium macropores; many very fine fibrous roots; abrupt smooth boundary to: 28-34 cm brown (7.5YR 5/3) heavy clay loam with a few strong brown (7.5YR 5/6) mottles; a few small subangular stones; weakly developed medium and coarse subangular 2 Safeguarding our Soils: a Strategy for England (Defra, 2009) 3
blocky structure; firm consistency; 2% fine macropores; common very fine fibrous roots; common ferri-manganiferous concentrations; clear smooth boundary to: 37-80+ cm Yellowish red (5YR 4/6) clay with many distinct reddish grey (5YR 5/2) and reddish yellow (5YR 6/8) mottles; common very small and rounded quartzite stones; very weak coarse prismatic structure becoming massive below; firm consistency; 0.1% very fine macropores; common ferri-manganiferous concretions; a few very fine fibrous roots. 2.6 These soils are slowly permeable and affected by waterlogging in winter because of slow movement of water through the lower subsoils (wetness class III or IV) They have a limited capacity to absorb excess winter rainfall and a moderate capacity to absorb or attenuate pollutants falling on the soil surface. Loamier soils 2.7 Near the bottom of the slope is a strip of soils where the topsoils are medium clay loam or sandy clay loam overlying similar textured upper subsoils extending to more than 50 cm depth before clay is encountered. The upper subsoils are relatively permeable and this reduces the degree of winter wetness in the soils (wetness class ii or III). 4
3.0 Agricultural Quality 3.1 To assist in assessing land quality, the Ministry of Agriculture, Fisheries and Food (MAFF) developed a method for classifying agricultural land by grade according to the extent to which physical or chemical characteristics impose long-term limitations on agricultural use for food production. The MAFF Agricultural Land Classification (ALC) system classifies land into five grades numbered 1 to 5, with grade 3 divided into two sub-grades (3a and 3b). The system was devised and introduced in the 1960s and revised in 1988. 3.2 The agricultural climate is an important factor in assessing the agricultural quality of land and has been calculated using the Climatological Data for Agricultural Land Classification 3. The relevant site data for an average elevation of 20 m is given below. Climate is not on its own a limiting factor in this area. Average annual rainfall: January-June accumulated temperature >0 C Field capacity period (when the soils are fully replete with water) Summer moisture deficits for: 703 mm 1448 day 169 days Early Nov-late April wheat: 103 mm potatoes: 93 mm 3.3 The survey described in the previous section was used in conjunction with the agroclimatic data above to classify the site using the revised guidelines for agricultural land classification issued in 1988 by the Ministry of Agriculture, Fisheries and Food 4. SURVEY RESULTS 3.4 The land is classified as grade 3, mostly in sub-grade 3b. 3 Climatological Data for Agricultural Land Classification. Meteorological Office, 1989 4 Agricultural Land Classification for England and Wales: Guidelines and Criteria for Grading the Quality of Agricultural Land. MAFF, 1988. 5
Sub-grade 3a 3.5 This sub-grade occurs in parts of the site on soils similar to those described in paragraph 2.7, mainly on the lower slopes beside the valley. The land can be wet in late autumn and spring because of water ponding over the subsurface clay layers or from local groundwater over the alluvium (wetness class II or III), but to a lesser extent than in the sub-grade 3b land described below. This slightly restricts workability and increases the risk of poaching damage from over-wintering animals. Sub-grade 3b 3.6 This sub-grade occurs in parts of the site on soils similar to those described in paragraph 2.4, with evidence of soil wetness within 45 cm of the soil surface The topsoils are wet from late autumn to early spring because of water ponding over the subsurface clay layers (wetness class III or IV) and this leads to poor workability and poaching damage from over-wintering animals. Other land 3.7 Near the farm buildings some of the land is used as garden, and some land is used for exercising horses. Grade areas 3.7 The boundaries between the different grades of land are shown on Map 1 and the areas occupied by each are shown below. Table 1. Areas within the survey area occupied by the different land grades Grade/sub-grade Area (ha) % of site Sub-grade 3a 1.06 25 Sub-grade 3b 2.96 70 Other land 0.02 5 Total 4.22 100 6
APPENDIX LOCATION AND DETAILS OF OBSERVATIONS 7
Agricultural land quality survey of land at Mindale House - Details of observations at each sampling point Obs Topsoil Upper subsoil Lower subsoil Slope Wetness Agricultural quality No Depth Texture Stones Depth Texture Mottling, Depth Texture Mottling ( ) Class Grade Main limitation (cm) (%) (cm) etc (cm) 1 0-30 HCL 1 30-60 SCL xxx 60-110 SCL xx 1 II 3a W 2 0-32 ca HZCL 1 32-45 ZC xxx 45-110 ZC xxxx 0 IV 3b W 3 0-35 SCL 0 35-50 SCL xx 50-80 HSCL xx(x) 1 III 3a W 80-110 C xxx 4 0-28 HCL 1 28-40 C xxx 40-110 rb C xxx 2 IV 3b W 5 0-30 MCL-SCL 0 30-60 MCL-SCL x 60-110 HCL xx 0 II 2/3a W 6 0-20 HCL 0 C+HCL mixed soil bund 0 III 3b W 7 HCL topsoil and subsoil mixed 3b w 8 0-28 HCL 1 28-34 HCL xx 32-110 rb C xxx 3 IV 3b W 9 0-35 MCL 0 35-55 HCL xx 55-110 rb C xxx 4 III 3a W 10 0-35 MCL 1 35-80+ rb C xxx 4 IV 3b W 11 0-30 HCL 1 30-60 C xxx 60-110 C xxx 4 IV 3b W 12 0-30 HCL 1 30-60 rb C xx(x) 60-110 rb C xxx 4 III 3b W 13 0-25 MCL 1 25-35 MCL xx 35-110 rb C xxx 3 IV 3b W Key to table Mottle intensity: Texture: Limitations: o unmottled C - clay W - wetness/workability x few to common rusty root mottles (topsoils) ZC - silty clay D - droughtiness or a few ochreous mottles (subsoils) SC - sandy clay De - depth xx common to many ochreous mottles and/or dull structure faces CL - clay loam (H-heavy, M-medium) St stoniness xxx common to many greyish or pale mottles (gleyed horizon) ZCL - silty clay loam (H-heavy, M-medium) Sl slope xxxx dominantly grey, often with some ochreous mottles (gleyed horizon) SCL - sandy clay loam F - flooding SZL - sandy silt loam (F-fine, M-medium,C-coarse) T topography/microrelief SL - sandy loam (F-fine, M-medium, C-coarse) LS - loamy sand (F-fine, M-medium, C-coarse) Texture suffixes & prefixes: S - sand (F-fine, M-medium, C-coarse) rb reddish brown; gy grey; dk - dark LP loamy peat; P - peat chk - chalk a depth underlined (e.g. 50) indicates the top of a slowly permeable layer