Dataset: Broadbalk changes in Olsen P in top soil, 1843-2010

Citation:  Rothamsted Research (2016). Broadbalk changes in Olsen P in top soil, 1843-2010 Electronic Rothamsted Archive, Rothamsted Research 10.23637/keyrefoabkolsenp
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Open Access BK Olsen P

Open Access BK Olsen P


Summary data showing changes in plant-available phosphorus (Olsen P) in the topsoil (0-23cm) of selected plots of the Broadbalk Wheat experiment, 1843-2010.


Until 2000, most of the Broadbalk plots had received superphosphate P (35 kg P ha-1) each year since 1852. Since 2001, applications of P have been withheld on some plots. The accumulation of available P was greatest on the FYM plot, reflecting the larger total P inputs in FYM (approx 45 kg P ha-1) compared to that applied as inorganic fertilizer or where no P was applied. The greater Olsen P concentrations on plot 5 (PKMg) compared to plot 8 (N3PKMg), despite their similar P inputs, were a result of the higher yields and greater P offtakes in the crop on plot 8, due to the applied N. Plot 18 (N4 1/2PKMg) received P at half the standard rate between 1852 and 2000, resulting in relatively low Olsen P concentrations. Since 2001 fertilizer P has been applied at the full rate on this plot, and there has been a corresponding increase in Olsen P. Olsen P concentrations were least on plots receiving no (or very little) P inputs in fertilizer (plot 3, given no fertilizer or manure). Since 2001, fertilizer P has not been applied to plots 5 and 8 (and others not shown), due to the high reserves of plant-available P in the soil. This is reviewed each year.

Technical Information

Plant-available phosphorus (Olsen P) is measured by extracting soil with a solution of 0.5M NaHCO3, buffered at pH 8.5. The values for 1843 were estimated, although it is unlikely that all treatment strips would have started at the same value. Soils sampled before 1966 were analysed in 2001-4. Data is mean of all sections, both continuous wheat and wheat in rotation.

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Dataset Access and Conditions

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Rothamsted Research


Creative Commons License This dataset is available under a Creative Commons Attribution Licence (4.0).

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YOU MUST CITE AS: Rothamsted Research (2016). Dataset: Broadbalk changes in Olsen P in top soil, 1843-2010 Electronic Rothamsted Archive, Rothamsted Research

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Table Of Contents

Soil Olsen P from the following plots:

  • Plot 3: no fertilizer or manure since 1852
  • Plot 5: PKMg 1852-2000; no P since 2001
  • Plot 8: PKMg + 144 kg N 1852-2000; no P since 2001
  • Plot 2.2: 35t FYM since 1843
  • Plot 10 96 kg N 1852-2000, 192 kg N since 2001. No PKMg
  • Plot 18 96 kg N 1852-2000 + half normal PKMg until 2000; 192 kg N + PKMg since 2001

This dataset is derived from measurements made by the Analytical Chemistry Unit, Rothamsted Research, Harpenden. The data presented is mean data from selected plots only. The complete data set, including the raw data used to derive the mean values, is available from the e-RA curators.

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.

  • The dataset Broadbalk changes in Olsen P in top soil, 1843-2010 is a published dataset from the e-RA Database. e-RA is part of the Rothamsted Long-Term Experiments - National Bioscience Research Infrastructure (RLTE-NBRI), which also covers maintenance of the Long-Term Experiments, the Rothamsted Sample Archive and Rothamsted's environmental monitoring activities including the weather stations and its role in the UK Environmental Change Network
  • The RLTE-NBRI is funded by UK Research and Innovation - Biotechnology and Biological Sciences Research Council (UKRI-BBSRC) under award BBS/E/RH/23NB0007 (2023-2028). The RLTE-NBRI is also supported by the Lawes Agricultural Trust. e-RA has been part of a National Capability since 2012, previous awards from the BBSRC were Grants BBS/E/C/00005189 (2012-2017) and BBS/E/C/000J0300 (2017-2022)
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