DOI: 10.23637/rbk1-1796346264-1
title: Dataset: Broadbalk Wheat annual grain and straw yields 1852-1925

description: Mean annual grain and straw yields for each treatment strip of the Broadbalk Wheat Experiment, 1852-1925. Also other agronomic information, including sowing and harvest dates, amount, type and date of application of treatments, and winter wheat cultivars.
description: The treatment strips (plots) extend the whole length of the field, each testing a different fertilizer or manure treatment. In some years, the strips were divided into two or more sub-plots. Annual yield data presented here for each strip is the mean of all sub-plots, except when the fertilizer treatments were different (plots 9a and 9b, 15a and 15b, selected years), or if a sub-plot received a different treatment for one year, when it was excluded from the mean. See 'Broadbalk plan and cropping 1852-1925' for full details. Yield data from 1844-1851 is not included, as the fertilizer treatments were not fully established until 1852.
description: *Note* the Excel file: _*01-BKyield1852-1925.xlsx*_ contains the same data as the CSV files listed below. The Excel file contains each of the CSV files as an Excel worksheet and is provided for users who prefer Excel over CSV.

### Contents

|File|Dataset Name|Description|
|----|------------|-----------|
|README.html|Read me|File describing and explaining all details of the dataset (html) 
|README.txt|Read me|File describing and explaining all details of the dataset (txt)
|crop_data.csv|crop yield data|The main data table containing mean annual grain and straw yield data for all strips (plots) and details of all fertilizer and manure treatments, 1852-1925. Also other agronomic information, including sowing and harvest dates, amount, type and date of application of treatments, and winter wheat cultivars. The strips extended the whole length of the field; each strip tested a different fertilizer or manure treatment. Most strips were divided into two or more sub-plots for many of the years 1852-1925. Annual yield data for each strip (plot) is the mean of all sub-plots, except when the fertilizer treatments were different (plots 9a and 9b, 15a and 15b, notes 6-7). If a sub-plot received a different treatment for one year it was excluded from the mean (notes 2-4). See notes and plan for full details. |
|fym_factor_data.csv|FYM treatment factor level description|Describes the FYM (farmyard manure) treatment factor levels used|
|rape_cake_factor_data.csv|Rape cake treatment factor level description|Describes the rape cake (a type of organic manure) treatment factor levels used |
|n_factor_data.csv|N fertilizer treatment factor level descriptions|Describes the different N (nitrogen) fertilizer treatment factor levels used|
|p_factor_data.csv|P fertilizer treatment factor level descriptions|Describes the P (phosphorus) fertilizer treatment factor levels used|
|k_factor_data.csv|K fertilizer treatment factor level descriptions|Describes the K (potassium) fertilizer treatment factor levels used|
|na_factor_data.csv|Na fertilizer treatment factor level descriptions|Describes the Na (sodium) fertilizer treatment factor levels used|
|mg_factor_data.csv|Mg fertilizer treatment factor level descriptions|Describes the Mg (magnesium) fertilizer treatment factor levels used|
|notes_data.csv|Notes|Additional explanatory notes for records in the crop_data table, including details of sub-plots.
description: Wheat grain and straw yields have been recorded every year since the experiment began, with the first harvest in 1844 (the crop was sown in autumn 1843). Dried grain and straw samples have also been kept for chemical analysis since 1844; these are preserved in the Rothamsted Sample Archive. Yields are expressed at field moisture content, 
approximately 85% dry matter.
description: Mean yields are derived from the individual sub-plot yields of grain and straw in the BKYIELD dataset in the e-RA database. The Broadbalk 'White Books' , held in the Rothamsted Library Archive, were used to check the treatments applied to the sub-plots. In accordance with the Joint Code of Practice for Research at Rothamsted, data processing in e-RA follow rigorous standard operating procedures to ensure the quality and correctness of data collected in the field through to depositing in the e-RA database. To ensure quality control during data inputting, the data sets were typed on two separate occasions (double data entry). During the second typing (verification) the data values were compared with those typed on the earlier occasion, and any discrepancies were resolved before verification continued. This procedure also set out how to handle situations where the written records were illegible or ambiguous. This procedure avoided visual checking of data, which can be very inaccurate. Once the data were entered into e-RA, they were independently back-checked against the original data sheets. Individual sub-plot data can be accessed from the BKYIELD dataset in the e-RA database.