Spatial Variation in the Integrated Assessment of Pasture Dynamics and Soil Health on the North Wyke Farm Platform

This dataset contains measurements made in fields on the North Wyke Farm Platform, a national capability in South West England. These fields contained either permanent pasture or a Lolium perenne and Trifolium repens pasture, and were used as part of a beef and sheep livestock system. 10 locations were chosen in each field, 5 within 50 m of the field boundary and 5 closer to the middle of the field, and the latitude and longitude of each point is provided. At each location a range of measurements were made, including: percentage cover of plants and bare ground; leaf dry matter content; specific leaf area; pasture dry matter by rising plate meter; soil bulk density; soil organic matter; soil structure; earthworm counts and weights for different functional groups; and soil penetrometer readings.

The data collection took place on the North Wyke Farm Platform (NWFP), a UK National Bioscience Research Infrastructure in SW England. The NWFP is split into a number of self-contained farms (‘farmlets’) that are managed according to different operation philosophies or practices. The NWFP is highly instrumented and monitored, and core NWFP datasets are open and include in-situ water flow and chemistry taken at 15-minute intervals; 15-minute Met measurements; 15-minute soil moisture measurements; 30-minute GHG emissions; soils, crop and botanical field survey data; livestock and crop performance data; farm operational activities; and contextual information. See the related output section for further details on how to access these, and for a user guide detailing the NWFP design.

Samples were taken, or assessments made, on two of the NWFP farmlets. The green farmlet, with fields of permanent pasture, and the blue farmlet, where fields were sown with a mixture of high sugar ryegrass (Lolium perenne cv. AberMagic) and white clover (Trifolium repens cv. AberHerald). Plant species measurements and dry matter estimation by rising plate meter were done in 7 fields, and 6 of these fields also had soil analyses carried out in them. Stratified random sampling was used to find the sample locations. Each field was divided into two zones, the edge zone and the middle zone, indicated by an E or M respectively in the Site column of the data files. The edge zone was within 50 m of the field boundary, whereas the middle zone was greater than 50 m from the field boundary. Within these zones, the actual sample locations were chosen using a random generator. SamplingLocations.csv describes the farmlet, fields (including Field_Code, which can be used to join the data to other NWFP data), and the sample location latitude and longitude as measured by the rising plate meter.

At each location, the percentage cover and identity of all species (or bare ground) in a 50 cm x 50 cm quadrat was surveyed (see Plant.csv). Leaves were taken from each species in the quadrat for analysis in the lab (leaf area, leaf dry matter content, specific leaf area). The protocol was to select the relatively young but fully expanded and hardened leaves from adult plants. Leaves with obvious symptoms of pathogen or herbivore attack, or with a substantial cover of epiphylls, were avoided. To give the fairest comparison across individuals and species, the outer canopy leaves (also called sun leaves) were sampled where possible.

Soil samples were taken for bulk density by hammering a circular metal ring into the surface soil and taking the intact soil sample. The ring was 10 cm deep, with a diameter of 6.6 cm. Soils were assessed for bulk density and soil organic matter by loss on ignition. Soil structure was assessed using the visual evaluation of soil structure (VESS) method, developed by SRUC, and as part of this, earthworm counts and weights were assessed. Results are presented in Soil.csv. This file also contains the pasture dry matter measurements made by a rising plate meter.

Penetrometer.csv has the results of a cone penetrometer assessment of soil bearing capacity and compaction. The standard cone tip was attached, the penetrometer placed vertically on the soil surface, and the cone pushed into the soil at a constant speed. The required force was measured at depth intervals of 2.5 cm. Locations differ in the maximum depth to which the assessment is made for various reasons, including soil hardness, obstacles, equipment limitations and geological conditions.

Further details about sample collection or analysis are presented in Column_units_and_descriptors.csv, where appropriate.