DOI: 10.23637/rpg5-pgherbnutris-1
title: Dataset: Park Grass herbage nutrients 2000-2024

description: This dataset contains the herbage nutrient data (N, P, K, Ca, Mg, Na and S), of all 101 individual sub-plots of the Park Grass hay experiment, each year 2000-2024, specifically % nutrient and nutrient uptake kg/ha-1 for both 1st and 2nd cuts. Nutrient uptake is calculated from the % nutrient and yield data which are also provided. A separate file of 5-year mean nutrient data (% and uptakes) in a regular format is also part of this dataset. Prior to 2000, herbage samples were not routinely analysed, but these intermittent data will be available in future (see Additional Information below).

Nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulphur (S) are essential nutrients for plant growth, while sodium (Na) can provide beneficial support in some functions. These nutrients are supplied by soil reserves and fertilisers, influencing plant productivity, species composition, and forage quality. These herbage nutrient data from the Park Grass experiment shows that nutrient concentrations vary widely depending on fertiliser inputs, soil pH, yield, and legume content. For example, P and K applications increase their respective concentrations and total uptake, lime boosts Ca availability, and high K inputs can suppress Mg and Na uptake, with implications for plant health and grazing livestock. Atmospheric inputs of N and S have declined over recent decades. N dynamics reflect both fertiliser use and natural sources such as legumes and soil organic matter. Uptake data highlight strong interactions between nutrients and management practices, demonstrating how balanced fertilisation and liming are key to sustaining yields and nutrient status. These herbage nutrient data are discussed in Poulton et al. (2026).
description: <b> Herbage sampling</b> Since 2000, samples from all plots for both cuts have been oven-dried and ground &lt; 0.5 mm and usually analysed for N, P, K, Ca, Na and S. 

<b> Nutrient analyses</b> 
Total N in herbage is determined by combustion analysis based on the Dumas combustion method (CN928 and a CN628Analyser, Leco Corporation, St Joseph, Michigan, USA). Total P was determined after dry ashing (Piper, 1942), on a Spekker, Technicon AutoAnalyzer or using Alpkem Flow Injection Analysis using the method of Fogg and Wilkinson (1958) until the 1990s and now using the method of Murphy and Riley (1962) by Continuous segmented colourimetric flow analyser (Skalar SANPLUS, Skalar Analytical BV, Breda, Netherlands). Cations were measured after dry ashing, by emission (K, Na, Ca) or atomic absorption (Mg) spectrophotometry (Unicam SP 90A Series 2 Atomic Absorption Spectrophotometer and Shandon Southern, Baird Atomic A 3400 Atomic Absorption Spectrophotometer) and now by nitric perchloric digestion (Zarcinas,1987) and analysis by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) (Agilent 5900 SVDV ICP-OES Agilent Technologies 5301 Stevens Creek Blvd. Santa Clara, CA 95051, USA.) or UK - LDA UK Limited, 5500 Lakeside, Cheadle Royal Business Park, Stockport, Cheshire SK8 3GR (UK supplier).
description: 1. <b>A FAIR data Excel file</b> PG-herbnutris-data-2000-2024_01.xlsx, contains annual Park Grass herbage nutrients 2000-2024. Frictionless CSV files are also provided.

2. <b>A Simple Excel file</b> rPG-herbnutris-5-yr-means-simple-data-2000-2004-01, that provides the data in a readily readable tabular format, containing separate sheets:
- <b>Nitrogen</b> Data table containing 5-yr means of % nitrogen and uptakes of nitrogen
- <b>Phosphorous</b> Data table containing 5-yr means of % phosphorous and uptakes of phosphorous 
- <b>Potassium</b> Data table containing 5-yr means of % potassium and uptakes of potassium 
- <b>Calcium</b> Data table containing 5-yr means of % calcium and uptakes of calcium 
- <b>Magnesium</b> Data table containing 5-yr means of % magnesium and uptakes of magnesium 
- <b>Sodium</b> Data table containing 5-yr means of % sodium and uptakes of sodium 
- <b>Sulphur</b> Data table containing 5-yr means of % sulphur and uptakes of sulphur 
- <b>Notes</b> Note alerts regarding some missing years of data
description: This dataset is from measurements led by Andy Gregory, Andy Macdonald Paul Poulton, and previous scientists, and latterly analysed by the Analytical Chemistry Unit, Rothamsted Research, Harpenden, see list of contributors. The data have been calculated by Suzanne Clark and collated into this FAIR dataset by Sarah Perryman, checked by Margaret Glendining. 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. <b> Farm Plot Numbers </b>
This dataset 2026 also contains the current farm plot numbers, 1 to 101, to enable easier sorting of the Excel file rows. These are the plot numbers used by the Rothamsted farm staff to manage the experiment treatments. Each individual sub-plot has a unique number 1-101: There are four sub-plots (a,b,c,d) per plot and 28 whole plots (relating to different fertilizer treatments) - except , plot 19 and plot 20 =3 sub-plots, plot 6=2 sub-plots, plot 18.2 = 1 plot d and plot 5= 0 sub-plots (as plot 5 and plot 6c& dis not part of the main Park Grass experiment, instead is used for micro-plot experiments). Thereby 23x4 + 2 +3 + 2 +1 = 101 total. They start at plot 3 and zig-zag up and along the experiment. They are presented alongside the traditional plot numbers and new plot IDs. 

<b> Nutrient data pre-2000 </b>
Data prior to the year 2000 was intermittent and will be made available at a later date. It consists of 2 x 10-year sets of means produced by Lawes and Gilbert, followed by samples bulked together in the 1920s, 1940s and 10960s according to yield published by Johnston in 1965. From the 1980s and 1990s more and more plots were added to the samples analysed until the whole number of plots have been analysed from 2000. 

<b> New plot ids </b>
From 2025, an additional plot identification number, "new_plot_id" uses a new naming convention assigned retrospectively to all plots since the start of the experiment in 1856. It is intended to show the provenance of the treatments of the plots using ' \ ' and '.' to indicate significant changes, where ' \ ' indicates a liming change and '.' indicates a plot-split for a fertilizer modification. For example, original plot number id., 7\1a now also has the new plot id., 7.1\L\a, where 7.1 indicates it has been split, for a new fertilizer treatment, and \L\a indicates the changes in liming it has undergone (where L a indicates a limed half pre-1964 and a indicating lime to pH 7 from 1965.