Reading Agricultural Consultants

Transcription

1 Reading Agricultural Consultants Knowle Park Initiative, Cranleigh Agricultural Land Quality Appraisal October 2014 Beechwood Court, Long Toll, Woodcote, Reading, RG8 0RR

2 1. Introduction 1.1. Instruction Reading Agricultural Consultants Ltd (RAC) is instructed by Bespoke Property Consultants of behalf of Messrs A Spriggs and N Vrijland to undertake an appraisal of the likely quality of agricultural land at Knowle Park, Cranleigh This appraisal is based on existing available data sources, including: Provisional Agricultural Land Classification of England and Wales, 1:250,000 and 1:63,360; Natural England s post-1988 Agricultural Land Classification data for the surrounding locality; the Soil Survey of England and Wales 1:250,000 scale soil association maps; climatic data derived from the Meteorological Office s standard 5km grid point data set; Natural England s map of the Likelihood of Best and Most Versatile Land for Surrey; and the findings of a detailed soil and Agricultural Land Classification survey undertaken by RAC for land to the immediate north of this site. 2. Site and Climatic Characteristics 2.1. General Features, Land Form and Drainage The site extends to approximately 37ha to the south-west of Cranleigh and includes arable land, grassland and woodland to the east of Alford Road, and a horticultural nursery to the west of Alford Road. The western part of the site is relatively level at around 47-48m above Ordnance Datum (AOD), whilst the land to the east of Alford Road rises slightly along the valley floor to 57m AOD in the east, and also to about 70m AOD to the south at Knowle Park. The land drains to the west to the River Wey Agro-climatic Factors Local agro-climatic factors have been interpolated from the Meteorological Office s standard 5 km grid point data set for the site at a representative altitude, and are given in Table 1. Average annual rainfall is relatively high and temperatures are warm for lowland England. Average moisture deficits are moderately large. The Field Capacity Day (FCD) regime is relatively large and is considered to be slightly unfavourable for providing opportunities for landworking. RAC

3 Table 1: Local Agro-climatic Factors Average Annual Rainfall (AAR) Accumulated Temperature >0 C (AT0) Field Capacity Day regime (FCD) Average Moisture Deficit, wheat (MDw) Average Moisture Deficit, potatoes (MDp) 785mm 1473 day 166 days 107mm 101mm 2.3. Soil Parent Material and Types The principal underlying geology is that of the Weald Clay Formation which consists of mudstone The Soil Survey of England and Wales 1:250,000 scale soil association maps (Figure 1 below) show two soil types at this site: Shabbington association mostly to the west of Alford Road; and Wickham 1 association to the east. Figure 1: Soil associations Wickham soils are mapped in green and Shabbington soils in blue (Soil Survey of England and Wales, 1984) The Shabbington association comprises soils which are commonly found adjacent to or just above river floodplains and are typically developed in fine loamy drift and rest on sandy material, with mottles present immediately below the topsoil. Shabbington soils are seasonally waterlogged, even with drainage, and are typically of Wetness Class (WC) III or IV, imperfectly to poorly drained. RAC

4 The Wickham 1 association typically comprises variably stony fine silty or fine loamy soils overlying clay. Soils are typically waterlogged seasonally and often assessed as being of WC IV, poorly drained. 3. Agricultural Land Quality 3.1. Provisional ALC Data There is no detailed Agricultural Land Classification (ALC) information available for the site. The Provisional ALC map (originally at a scale of 1:63,360 and latterly at 1:250,000) shows most of the land to the east of Alford Road as undifferentiated Grade 3 land (in green), with a strip of non-agricultural land (in orange) along the northern boundary. The land to the west of Alford Road is shown as Grade 2 (in blue, see Figure 2 below). Figure 2: Provisional Agricultural Land Classification (Ministry of Agriculture, Fisheries and Food, 1972) However, it is acknowledged by Natural England 1 that the Provisional ALC is only suitable for strategic purposes, and should not be used for assessing the quality of individual sites. In addition to the limitations of scale of this material, the classification of land was undertaken using a methodological approach which has undergone two fundamental revisions, and does not distinguish between the subgrades of Grade 3. This has important policy implications, in that Subgrade 3a is included amongst the best and most versatile land (along with Grades 1 and 2), whilst less weight is afforded to the loss of Subgrade 3b land. 1 Natural England (2012), Technical Information Note TIN 049, Agricultural Land Classification: protecting the best and most versatile agricultural land RAC

5 The likelihood that land is of best and most versatile quality is depicted in a map in Figure 3, prepared by Natural England. The predictions use soil associations (which are the mapping unit of the published 1:250,000 scale national soil map) as the main basis of assessment. The map is also intended for strategic planning purposes and is not suitable for use for the definitive classification of any local area or site. Nevertheless, the map indicates that there is a less than 20% likelihood of best and most versatile agricultural land over most of the site, with a higher likelihood on land to the west. Figure 1: Likelihood of best and most versatile quality agricultural land (Natural England, 2012) Detailed ALC data is available from MAFF for a site of approximately 65 ha to the east of Cranleigh at Ewhurst Green. Of the total, around 7 ha are classified as Subgrade 3a, but the majority is classified as Subgrade 3b Of most relevance though are the results of a detailed ALC survey undertaken by RAC on land to the immediate north of this site. Seventeen soil profiles were examined using an Edelman (Dutch) auger and spade in March 2014, at an observation density of one per hectare which is the density recommended in Natural England s Technical Information Note 049 for ALC surveys. At each observation point the following characteristics were assessed for each soil horizon up to a maximum of 120cm or any impenetrable layer: soil texture; significant stoniness; colour (including local gley and mottle colours); consistency; structural condition; presence of compaction and smearing; RAC

6 presence of anaerobic conditions; free carbonate; and depth The soil parent material and the soil associations on the land to the north are the same as those on the current site (although in different proportions). The survey found that the land to the north was predominantly (75%) classified as moderate quality Subgrade 3b land, with about 4ha or 25% classified as Subgrade 3a. Poorly permeable clay subsoils (typically associated with the Wickham soils) are limited to Subgrade 3b on a soil wetness limitation, and the sandier soils more typically associated with the Shabbington soils were limited by soil droughtiness to Subgrade 3a or 3b Site Assessment By collating all available data and assessing the site according to the criteria as set out in the MAFF revised guidelines ( ), it is apparent that most of the site will reflect the Wickham soils on the site to the north, and will be limited by soil wetness to Subgrade 3b A typical soil profile of the Wickham series is given in Appendix 1. Soils are mottled from the top of the profile and slowly permeable clay is encountered between 20 and 40 cm. Assessed in conjunction with local agro-climatic data, soils are considered to be of WC IV according to Figure 7 of the MAFF revised guidelines (Appendix 2) With a FCD regime of 166 days, Wickham soils of WC IV with a typical silty clay loam or clay loam topsoil texture are assessed as being of Subgrade 3b quality according to Table 6 of the MAFF revised guidelines (Appendix 3) The area shown as Shabbington association in Figure 1 which, from the survey work carried out for the site to the north, would be expected to be generally higher quality than the Wickham soils but limited by droughtiness to Subgrade 3a or 3b, has been developed mostly as a horticultural nursery. The ALC guidelines include agricultural buildings amongst the Other land categories such that the land to the west of Alford Road will be defined as non-agricultural and will not be assigned to a grade of land between 1 and 5 (see extract from the ALC guidelines in Appendix 4). There is a small area to the immediate east of Alford Road which is also shown as Shabbington soils, and which could be limited by droughtiness to Subgrade 3a or Subgrade 3b Therefore, the evidence is that of the total site area of approximately 37ha, about 23ha (62%) will be classified as Subgrade 3b, 1ha (3%) to the immediate east of Alford Road may be classified as either Subgrade 3a or 3b, and the remaining 13ha (35%) will be classified as non-agricultural land (either existing woodland or agricultural buildings). 2 MAFF (1988). Agricultural Land Classification of England and Wales. Revised guidelines and criteria for grading the quality of agricultural land. MAFF Publications RAC

7 Appendix 1: Soil profile descriptions Source: Soil Survey of England and Wales, Soils and their Use in South East England. Wickham Series Profile no: TQ 64/0792 Definition: Typical stagnogley soils. Fine loamy or fine silty drift over clayey passing to clay or mudstone. Elevation: 42 m O.D. Slope and aspect: 1 NNE, straight. Land use: Orchard. Horizons 0-22 cm, Ah. Dark greyish brown (10YR4/2) very slightly stony silty clay loam with few fine greyish brown (10YR5/2) mottles; medium subangular and tabular, chert; moist; moderately developed medium subangular blocky; medium packing density; moderately firm soil strength; many very fine fibrous roots; non calcareous; clear wavy boundary cm, Eg. Brown (10YR5/3) slightly stony silty clay loam with many fine strong brown (7.5YR5/6) mottles; medium subrounded and tabular, chert; very moist; weakly developed, adherent coarse subangular blocky with light brownish grey (2.5Y6/2) faces; medium packing density; moderately firm soil and ped strength; common very fine fibrous roots; non calcareous; few rounded ferruginous concretions; gradual wavy boundary cm, 28tg. Light grey (5Y7/1) slightly stony silty clay with many fine strong brown (7.5Y5/8) mottles; medium subangular and tabular, chert; very moist; weakly developed, adherent medium prismatic; high packing density; moderately firm soil and ped strength; few fine fibrous roots; very slightly calcareous; gradual wavy boundary cm, 28cg. Light grey to grey (5Y6/1) stoneless silty clay with many fine strong brown (7.5YR5/8) mottles; moist; weakly developed, adherent coarse, prismatic; high packing density; very firm soil and ped strength; very slightly calcareous. Horizon: Ah Eg 28tg 28cg Depth (cm) Sand 600 µm-2 mm % µm % µm % Silt 2-60 µm % Clay <2 µm % < 0.2 µm % CaCO 3 equivalent % Organic carbon % ph in water (1:2.5) ph in 0.1M CaCl 2 (1:2.5) Bulk density g cm Available water capacity % vol. < 2 bar < 15 bar Air capacity % vol Retained water capacity % vol Illuvial clay % 0 <1 >2 >2 RAC

8 Appendix 2: Figure 7 of the MAFF revised guidelines RAC

9 Appendix 3: Table 6 of the MAFF revised guidelines RAC

10 Appendix 4: Description of the Grades and Subgrades (extract from the ALC Guidelines) The ALC grades and subgrades are described below in terms of the types of limitation which can occur, typical cropping range and the expected level and consistency of yield. In practice, the grades are defined by reference to physical characteristics and the grading guidance and cut-offs for limitation factors in Section 3 enable land to be ranked in accordance with these general descriptions. The most productive and flexible land falls into Grades 1 and 2 and Subgrade 3a and collectively comprises about one-third of the agricultural land in England and Wales. About half the land is of moderate quality in Subgrade 3b or poor quality in Grade 4. Although less significant on a national scale such land can be locally valuable to agriculture and the rural economy where poorer farmland predominates. The remainder is very poor quality land in Grade 5, which mostly occurs in the uplands. Descriptions are also given of other land categories which may be used on ALC maps. Grade 1 -excellent quality agricultural land Land with no or very minor limitations to agricultural use. A very wide range of agricultural and horticultural crops can be grown and commonly includes top fruit, soft fruit, salad crops and winter harvested vegetables. Yields are high and less variable than on land of lower quality. Grade 2 -very good quality agricultural land Land with minor limitations which affect crop yield, cultivations or harvesting. A wide range of agricultural and horticultural crops can usually be grown but on some land in the grade there may be reduced flexibility due to difficulties with the production of the more demanding crops such as winter harvested vegetables and arable root crops. The level of yield is generally high but may be lower or more variable than Grade 1. Grade 3 --good to moderate quality agricultural land Land with moderate limitations which affect the choice of crops, timing and type of cultivation, harvesting or the level of yield. Where more demanding crops are grown yields are generally lower or more variable than on land in Grades 1 and 2. Subgrade 3a -good quality agricultural land Land capable of consistently producing moderate to high yields of a narrow range of arable crops, especially cereals, or moderate yields of a wide range of crops including cereals, grass, oilseed rape, potatoes, sugar beet and the less demanding horticultural crops. Subgrade 3b -moderate quality agricultural land Land capable of producing moderate yields of a narrow range of crops, principally cereals and grass or lower yields of a wider range of crops or high yields of grass which can be grazed or harvested over most of the year. Grade 4 -poor quality agricultural land Land with severe limitations which significantly restrict the range of crops and/or level of yields. It is mainly suited to grass with occasional arable crops (e.g. cereals and forage crops) the yields of which are variable. In moist climates, yields of grass may be moderate to high but there may be difficulties RAC

11 in utilisation. The grade also includes very droughty arable land. Grade 5 - very poor quality agricultural land Land with very severe limitations which restrict use to permanent pasture or rough grazing, except for occasional pioneer forage crops. Descriptions of other land categories used on ALC maps Urban Built-up or 'hard' uses with relatively little potential for a return to agriculture including: housing, industry, commerce, education, transport, religious buildings, cemeteries. Also, hard-surfaced sports facilities, permanent caravan sites and vacant land; all types of derelict land, including mineral workings which are only likely to be reclaimed using derelict land grants. Non-agricultural 'Soft' uses where most of the land could be returned relatively easily to agriculture, including: golf courses, private parkland, public open spaces, sports fields, allotments and soft-surfaced areas on airports/ airfields. Also active mineral workings and refuse tips where restoration conditions to 'soft' after-uses may apply. Woodland Includes commercial and non-commercial woodland. A distinction may be made as necessary between farm and non-farm woodland. Agricultural buildings Includes the normal range of agricultural buildings as well as other relatively permanent structures such as glasshouses. Temporary structures (e.g. polythene tunnels erected for lambing) may be ignored. Open water Includes lakes, ponds and rivers as map scale permits. Land not surveyed Agricultural land which has not been surveyed. Where the land use includes more than one of the above land cover types, e.g. buildings in large grounds, and where map scale permits, the cover types may be shown separately. Otherwise, the most extensive cover type will usually be shown. RAC