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Broadbalk open access data

Broadbalk Open Access Data

Selected data from our long term experiments is being made freely available to the scientific community, as prepared summaries of commonly requested data. This recognises the national and international importance of the data. The aim is that greater use of the data will lead to further understanding and wider benefits. Rothamsted relies on the integrity of the user to ensure that Rothamsted Research receives suitable academic acknowledgment as being the originators of these data, and offer assistance to users to help ensure that where these data are being applied they are represented and interpreted in a rigorous way. Please contact the e-RA curators for help with questions about the data or its interpretation.

Creative Commons License This work is licensed under a Creative Commons Attribution 4.0 International License.

The following Broadbalk Open Access Datasets are currently available:

Broadbalk Yields

The figure shows the mean long-term winter wheat yields from selected treatments on Broadbalk 1852-2016, excluding spring wheat in 2015. The changes reflect the improved cultivars and better control of pests, diseases and weeds that have been introduced on Broadbalk, especially since the 1960s. To control weeds, the experiment was divided into five sections in the 1920s and one section bare fallowed each year. The introduction of herbicides removed the need for fallowing. Yields of continuous wheat given no fertilizer or manure have remained at around 1 t ha-1. In 1968 a rotation was introduced on part of the experiment, so that it is now possible to compare the yields of wheat grown continuously and as the first wheat after a two year break. Since 1979 summer fungicides have been used, which has allowed us to exploit the greater grain yield potential of modern cultivars. From 1985, two higher N rates have been tested, 240 and 288 kg N ha -1. The highest yields are now from the first wheat crop in rotation, with the greatest yields from fertilizer alone exceeding those from FYM alone, and the combination of FYM + 96 kgN ha-1 (144 kgN ha-1 since 2005) often exceeding both. The largest annual wheat yields on Broadbalk (>13 t ha-1) were recorded in 2014, following the change in variety from Hereward to Crusoe.

The greatest yields were not always achieved with the highest N rate. The figure shows the mean greatest first wheat yields achieved from the NPK treatments, receiving up to a maximum of 288 kg N ha-1 (a maximum of 192 kg N ha-1 from 1968-1984).

Click to download chart Broadbalk Yields

Click the chart above for a PDF version. Data, and information on treatments, are available to download as an Excel Spreedsheet: Yield data and treatments. These data are freely available, no password is required, however users are requested to acknowledge Rothamsted Research as the data source.

Reference: Rothamsted Research (2006) "Guide to the Classical and other Long-term Experiments, Datasets and Sample Archive", pp 8-18. Lawes Agriculture Trust Co. Ltd, Harpenden, UK. See Rothamsted Guide to the Classical Experiments (2006).

For further information about the experiment see Broadbalk Winter Wheat Experiment.

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Broadbalk Soil Organic Carbon

The figure shows the long-term changes in soil organic carbon (SOC) (t ha-1) content in the topsoil (0-23 cm) in selected treatments of the Broadbalk experiment, where winter wheat has been grown each year since 1843 ("continuous wheat"). Data has been calculated from measured % SOC (0-23 cm) and standard soil weights, adjusted for observed decreases in topsoil bulk density of plots given FYM, by including the appropriate amount of subsoil to ensure soil weights were comparable over time. SOC has remained almost constant in the unfertilized plot, at the equilibrium level for this farming system on this soil type. Inorganic fertilizer (N3PK) has enhanced SOC a little, probably due to increased returns of organic matter in crop roots and above-ground crop residues. The treatment given FYM (35 t ha-1) since 1843 now contains almost three times as much SOC as the unfertilized plot. Increases due to FYM were greatest in the initial years of the experiment. The same trends can be seen in the FYM treatments that started in 1885 and 1968.

Click to download chart Broadbalk SOC Click the chart above for a PDF version. Data, information on treatments and methods of sampling and analysis, are available to download as an Excel Spreedsheet: SOC data and treatments. For further information about the fertilizer treatments see Broadbalk Fertilizer Treatments (pdf). For further information about the soil, including site details and soil weights, see Broadbalk Soils.

These data are freely available, no password is required, however users are requested to acknowledge Rothamsted Research as the data source.

Reference: Updated from Powlson et al, 2012. With thanks to Andy Macdonald and Paul Poulton for providing the data.

For further information about the experiment see Broadbalk Winter Wheat Experiment.

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Broadbalk soil: Concentration of Olsen P (plant-available P)

The figure shows changes in plant-available phosphorus (Olsen P) in the topsoil (0-23cm) of selected plots of the Broadbalk Wheat experiment. Olsen P, which is commonly used to assess plant-available P, is measured by extracting soil with a solution of 0.5M NaHCO3, buffered at pH 8.5. Until 2000, most of the Broadbalk plots had received superphosphate P (35 kg P ha-1) each year since 1844. 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 1844 and 2001, 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.

Click to download chart Broadbalk Olsen P

Click the chart above for a PDF version. Data, information on treatments and methods of sampling and analysis, are available to download as an Excel Spreedsheet: Olsen P data and treatments. For further information about the fertilizer treatments see Broadbalk Fertilizer Treatments (pdf). For further information about the soil, including site details and soil weights, see Broadbalk Soils .

These data are freely available, no password is required, however users are requested to acknowledge Rothamsted Research as the data source. With thanks to Andy Macdonald and Paul Poulton for providing the data.

For further information about the experiment see Broadbalk Winter Wheat Experiment.

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Key References

2016

2012

2009

1996

1993

1990

1983

1969

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