DOI: 10.23637/rbk1-trace2005-01
title: Dataset: Broadbalk wheat grain micronutrients 1845-2005

description: This dataset provides the element concentrations of the trace elements Se, Cu, Fe, Zn and Mg in the wheat grain of selected plots of Section 1 (continuous wheat) of the Broadbalk experiment, from 1845-2005. Grain yield, harvest index and grain offtake of the elements are also included. This is the data reported by Fan et al. (2008a, 2008b).
description: Archived grain samples were analysed in 2006 from strips 3, 7 and 2.2, from the equivalent of the current Section 1 (continuous wheat). They were taken at five-yearly intervals 1845-1965 and at two- or three- yearly intervals 1968-2005, a total of 41 samples from each plot.

Amounts of fertiliser and manure applied to the plots:
- **Plot 3** Control - no fertiliser or manure applied 1844-present
- **Plot 7** N2PKNaMgS (1849-1973); N2PKMgS (1974-2000); N2KMgS (2001-present)
- **Plot 2.2** FYM (1844-present)

See <i>Broadbalk Fertiliser and Manure Treatments 1852-2021</i> for details of amounts and types of fertiliser applied. Varying amounts of S applied, by default, as part of other S-containing fertilisers. Year refers to harvest year, the experiment was started in autumn 1843.
description: Broadbalk wheat grain micronutrient data (Se, Cu, Fe, Zn and Mg), grain yield and harvest index 1845-2005, plots 3, 7 and 2.2, Section 1. 

An Excel file, 01-trace2005.xlsx, contains the micronutrient data, grain yield, fertiliser and manure treatment details. CSV files are also provided.
description: Approximately 10g of each archived grain sample was rinsed briefly with deionized water, dried at 80 degrees C, and ground to &lt;0.5mm with a stainless steel centrifugal mill. Ground grain samples were digested with ultra pure HNO<sub>3</sub> and H<sub>2</sub>O<sub>2</sub> in microwave vessels. Concentrations of Se in the digests were measured by ICP-MS. Concentrations of Cu, Fe, Zn and Mg in the digests were measured by ICP-OES. 
Concentrations of Cu, Fe, Zn and Mg are in mg kg<sup>-1</sup>; concentrations of Se are in μg kg<sup>-1</sup>
See Fan et al., 2008a and b for further details. 

Harvest index is calculated as grain yield/(grain yield + harvested straw yield). Yields are at 100% dry matter. Straw yield is the straw and chaff removed at harvest, but does not include the stubble or all the chaff.
description: This dataset is derived from measurements made by the Analytical Chemistry Unit, Rothamsted Research, Harpenden. Grain and straw yields were cross checked with yield data already published for the Broadbalk experiment by e-RA: 
- 1845-1925 yields were taken from the e-RA database (https://www.era.rothamsted.ac.uk/) 
- 1930-1967 yields were taken from https://doi.org/10.23637/rbk1-yld2667-01
- 1968-2005 yields were taken from https://doi.org/10.23637/rbk1-yld6822-01 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. Updated 11/02/2025: Changed Strip name 21 to 2.1, 22 to 2.2