DOI: 10.23637/rex4-soil2012-01
title: Dataset: Exhaustion Land Experiment soil chemical properties 2012

description: Soil chemical properties of six plots of the Exhaustion Land Experiment, May 2012. Including soil C, N, pH, extractable cations and total elements. These plots were subsequently used for the datasets describing wheat growth and crop element uptake, and soil moisture and soil P and N dynamics, over the growing seasons 2013 and 2014.
description: Samples were taken from six plots: two P treatments - **Control** (P0) and **P added** (P3), each from three main plots: **Plot 3** (FYM 1876-1901) **Plot 7** (NPKNaMg 1876-1901) and **Plot 9** (P only 1876-1901). 


**Annual P treatments:** 
- **Control (P0)**: no P fertiliser applied since 1901 
- **P added (P3)**: 131 kgP/ha 1986-1992, 20kgP/ha 2000-2008, 15kgP/ha since 2009, all as triple superphosphate.
description: An Excel file, 01-soil2012.xlsx, contains the Exhaustion Land soil characterisation data for 2012. CSV files are also provided.
description: Soil samples (0-23cm) were taken in May 2012 with a 2.5cm diameter stainless steel auger, a minimum of nine cores on a "W" across the plots, aggregated, sieved to 2mm, mixed and air dried. A sub-sample was further processed, by fine grinding to pass a 44 mesh sieve or finer, using a Retsch Planetary ball mill to provide an analytical sample.

- **Soil pH** in water, with a soil:water ratio of 1:2.5. Air dried soil, sieved &lt;2mm
- **%N** by combustion analysis, based on the Dumas method, using a LECO combustion system to measure total N. Measured on air-dried, finely ground soil
- **%C** by combustion analysis, based on the Dumas method, using a LECO combustion system to measure total C. Measured on air-dried, finely ground soil
- **%CaCO3** analysed by a calcimeter. %IC derived from %CaCO3 by dividing by 8.333.
- **% organic C** calculated as total %C minus % inorganic C.
- **PO<sub>4</sub>-P**, by Olsen P. Air-dried, sieved &lt;2mm soil, mg/kg (Olsen et al, 1954). 
- **Al, Fe, Mn and P extracted by ammonium oxalate - oxalic acid**. Air dried, &lt;0.5mm fine ground soil, extract analysed by ICP-OES, mg/kg (Loeppert and Inskeep, 1996; Rayment and Lyons, 2011).
- **Al, Fe, Mn and P extracted by Dithionite** with citrate buffer, extract analysed by ICP-OES, mg/kg (Mehra and Jackson, 1960).
- **K, Mg** extracted by ammonium nitrate (NH<sub>4</sub>NO<sub>3</sub>), extract analysed by ICP-OES, mg/kg (MAFF/ADAS 1986).
- **Pseudo "total" element extraction** with Aqua Regia digestion: Al, As, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn
Na, Ni, P, Pb, S, Ti, Zn, extract analysed by ICP-OES, mg/kg (McGrath and Cunliffe, 1985). Data for Mo and Se omitted as they were below the detection limit.

 
<i>References in Additional Information.</i>
description: This dataset is derived from measurements made by Sarah Dunham and Javier Hernandez-Allica, and analysed by the Analytical Chemistry Unit, Rothamsted Research, Harpenden. The Analytical Chemistry Unit follows the Joint Code of Practice (JCoPR) and participates in European Quality Assurance programmes. All performance is strictly monitored using certified external standards alongside in-house standard materials. Standards and check samples are monitored and recorded. <i>References for methods of analysis: </i>
- **Loeppert, RH and Inskeep WP** (1996). Iron. In: Methods of Soil Analysis Part 3-Chemical Methods (Ed DL Sparks) pp639-664 No 5 Soil Science Society of America Book Series. Soil science Society of America Inc. and American Society of Agronomy Inc, Madison, Wisconsin, USA.
- **MAFF/ADAS** (1986) The Analysis of Agricultural Materials: A Manual of the Analytical Methods Used by the Agricultural Development and Advisory Service, Volume 427, HMSO, London, UK. 
- **McGrath, SP and Cunliffe, CH** (1985) A simplified method for the extraction of metals Fe, Zn, Cu, Ni, Cd, Pb, Cr, Co and Mn from soils and sewage sludge. J. Sci. Fd Agric. 36, 794-79
- **Mehra OP and Jackson ML** (1960), Iron oxide removal from soils and clays by a dithionite citrate system buffered with sodium bicarbonate, Clays and Clay Minerals 10, pp. 317–327. 
- **Olsen, SR, Cole, CV, Watanabe, FS and Dean, LA** (1954) Estimation of Available Phosphorus in Soils by Extraction with Sodium Bicarbonate. USDA Circular No. 939, US Government Printing Office, Washington DC
- **Rayment, GE and DJ Lyons** (2011) Extractable iron, aluminium and silicon. Section 13A1. In: Soil Chemical Methods-Australasia. CSIRO Publishing pp253-264