DOI: 10.5285/9ab5285f-e9c4-4588-ba21-476e79e87668
title: Soil near-surface properties, vegetation observations, land use and land management information for 1800 locations across the Thames catchment, UK, 2018-2021

description: This dataset contains information about soil near-surface physical and hydrological properties, vegetation observations and land use & management information across the Thames catchment (UK). It was collected during the ‘Landwise' project's ‘Broad-scale field survey' which sampled 1836 location points across a total of 164 fields/land parcels. The aim of the survey was to quantify the impact of innovative land use and management on soil properties, with implications for natural flood management. The surveyed fields were selected to represent four broad land use and management classes (arable with and without grass in rotation, permanent grassland and broadleaf woodland) and five generalised soil/geology classes. Approximately eight fields were sampled for each of the twenty combinations of land use and soil/geology class. The sampled fields cover a range of traditional and innovative agricultural practices. Within each field/parcel, representative sampling locations were selected to cover the anticipated range of soil variability, including typical infield, untrafficked margins and trafficked headlands/tramlines etc. Sampling was undertaken once during the period 2018-2021. Samples were measured and analysed using a range of field and laboratory techniques (see Data Lineage).

Point data include:
1.	Survey point location (British National Grid coordinates)
2.	Soil quantitative measurements (near-surface: 0 – 50 mm below ground level): dry bulk density, volumetric water content, organic matter, derived porosity, derived porosity accounting for variable organic matter, particle size distribution and texture classification
3.	Vegetation quantitative measurements: maximum and minimum height
4.	Soil qualitative measurements: hand texture classification, aggregate stability test slaking and dispersion results, hydrochloric acid test for calcareous soil, and for a subset of locations Visual Evaluation of Soil Structure (VESS) score
5.	Observations (also classified into groups): soil surface condition (e.g. slaked/unslaked/capped/poached etc.), vegetation type

Field contextual data include:
1.	Land owner/manager responses to a land use and management questionnaire (primary data) including information on: crop types/rotation, cover crops, herbal leys, organic or conventional, organic amendments, lime additions, tillage, last ploughed, tramlines, buffer strips, field drainage, grass species, livestock, last grazed, stocking density, grazing weeks per year, stock out-wintering, mob or paddock grazing, woodland management, tree species, woodland age, path management, land use history, flooding history, waterlogging, water or sediment runoff 
2.	Classification of selected questionnaire free text responses into categories (derived secondary data)
3.	General field observations (primary data) including: slope gradient and shape, surface form, surface water, surface condition (slaking, capped, ruts, wheelings, poaching etc.), soil erosion or deposition features

As agreed with the survey participants, this dataset has been anonymised by removing location specific information, such as farm and field names, along with any other personally identifiable information. As also agreed, point data location coordinates have been degraded to the nearest 1 km grid point.

The dataset was co-produced by the UK Centre for Ecology and Hydrology and Landwise Partners as part of the Landwise Natural Flood Management project, supported by the Natural Environment Research Council (Grant NE/R004668/1). The participation and assistance of the land owners and managers is gratefully acknowledged.

description: Survey participants (land owners/managers) were self-selecting. Survey areas were identified to fulfil the overall Landwise sampling strategy objective of sampling approximately 8 fields in each of the twenty Landwise land use/management and soil/geology class combinations. Participants completed a land use and management questionnaire for each sampled field/land parcel.

At each sampling point within a field, observations of vegetation type and soil surface condition were made. Volumetric soil samples were taken vertically from 0-50 mm below ground level (bgl) using an Eijkelkamp 50 mm internal diameter soil sampling ring. An additional (non-volumetric) soil sample was also taken by trowel. Soil samples were sealed in plastic bags and refrigerated on the day of collection prior to laboratory analysis. A soil sample from 0-50 mm bgl was also hand textured following Natural England (2008) TIN037. For selected sampling points, a Visual Evaluation of Soil Structure (VESS) score was determined.

The following laboratory analyses were undertaken. Soil dry bulk density and volumetric water content were determined by oven drying at 105°C for 36 h. Sub-samples from the additional soil samples were used for hand texturing and laser particle size distribution measurement (Malvern MasterSizer 2000). Air-dried sub-samples were used in an aggregate stability slaking and dispersion test. Soil organic matter was determined by loss on ignition in a furnace at 400°C for 16 h. Soil was tested for reaction to hydrochloric acid test to identify calcareous soil.

Field and laboratory data record transcriptions were independently verified. Calculated primary data were quality controlled by an independent assessor to flag any potential spurious values, correcting or removing the data as appropriate.

Secondary (derived) data were determined from the primary data. Soil porosity was calculated using dry bulk density, typical soil particle density percentage and optionally soil organic matter percentage and typical soil organic matter density. Secondary classifications (class groups) of questionnaire responses were made using spreadsheet filtering tools. Soil texture classes were determined from soil laser particle size distribution data using the R ‘soiltexture' package (Moeys et al., 2018).

Details of the variables (name, units and brief description) may be found in the Supporting Documentation:

LANDWISE_BroadScale_Survey_Field_Contextual_Data_PUBLIC_metadata.csv

LANDWISE_BroadScale_Survey_Point_Data_PUBLIC_metadata.csv

The following data limitations should be noted. Although field observations and measurements were taken following a consistent methodology, the different field teams had varying expertise and experience. A ‘SurveyStaffCode' has been provided for each data record to reflect this potential variation. Soil organic matter determined by loss on ignition is known to be an estimate. Derived soil porosity accounting for soil organic matter relies on an assumed typical organic matter particle density, which will be somewhat uncertain. Secondary classifications, although independently quality controlled, are an interpretation of free text responses and/or field observations and are therefore somewhat dependent on the data analyst.