DOI: 10.5285/6566a706-9c55-4f7f-b33d-27bc29c73274
title: Soil physical, chemical and biological measurements in the Conwy Catchment (North Wales) 2013 and 2014

description: The data consist of general physical, biological and chemical parameters for soil samples taken in the Conwy catchment in North West Wales. Samples were collected between 2013 and 2014 across a land use intensification gradient ranging from semi-natural peatlands, acid grasslands to improved grasslands and arable fields. Soil cores were taken to a depth of 1 metre and divided into 15 centimetre (cm) depth increments. General soil physical and chemical parameters were measured at each depth increment for most of the sites. Biological (root and fine root biomass) parameters were assessed in the topsoil 0-15 cm in 5 cm intervals. Soil parameters were tested across a land use intensification gradient to detect parameters that can predict aboveground biomass production across different land management types. Data were used to enhance the predictions of biomass production in the Joint UK Land Environment Simulator model (JULES). Measurements informed the improvement of the nitrogen cycle component in the model. Measurements were undertaken by trained members of staff from Bangor University, the Centre for Ecology & Hydrology and Exeter University.

This data was collected for the NERC project 'The Multi-Scale Response of Water quality, Biodiversity and Carbon Sequestration to Coupled Macronutrient Cycling from Source to Sea' (NE/J011991/1). The project is also referred to as Turf2Surf.
description: Intact soil cores were collected in spring 2014 using a Van Walt percussion (Cobra TT) core. Soil cores were taken to a depth of 1 metre and divided into 15 centimetre (cm) depth increments. Soil phosphorous was measured in detail using 5 different extraction methods. Standard Olsen-P was measured and compared to four alternative methods i.e. mimicking plant available phosphorous. Ion analysis was carried out using TXRF (Total X-Ray Fluorescence Analysis) S2 PICOFOX (Bruker). For nitrate analysis the vanadate methodology of Miranda et al. (2001) was followed. For ammonium analysis, the salicylate-nitroprusside and hypochlorite methodology of Mulvaney (1996) was followed. Dissolved Organic Carbon (DOC) and Total Dissolved Nitrogen (TDN) analysis was carried out using a Thermalox 5001.3 (Analytical Sciences Limited) instrument. For all soil available cations (Ca, Na, K) soil was extracted with 0.5 Acetic acid and analysis was conducted on the extracted solution. For all soil available C and N measurements soil was extracted with 0.5 M K2SO4 and analysis was conducted on the extracted solution. Total Carbon and Nitrogen (C_tot and N_tot) were analysed using thermal oxidation measured by an Elementar Vario Cube Select. Soil water content (SWC), Bulk density (BD) and Loss-on-ignition (LOI) and LOI-C were measured using standard techniques. To measure pH and conductivity a 1:2.5 ratio of soil to deionised (DI) water was used, so to 5g of soil 12.5 ml of DI was added. Samples were then placed on a flat-bed shaker for 30 minutes, removed and allowed to settle before measuring pH and EC using standard lab probes (Hanna 309 pH probe, UK; Jenway 4520 EC probe, UK). Biological (root and fine root biomass) parameters were assessed in the topsoil 0-15 cm in 5 cm intervals on six sites. Samples were prepared by removing any above ground vegetation, soil and stones.Roots were then scanned using the WinRhizo programme to measure parameters such as total root lengths, diameters and branching. Samples were then dried at 80 degrees Celsius to remove water content to calculate total root biomass (dry weight) and fine root biomass (dry weight).

All results were entered into Excel spreadsheets. Results from all the analyses were combined into one Excel spreadsheet. Data were then exported from this combined Excel spreadsheet as .csv files for ingestion into the EIDC.