DOI: 10.23637/wrn12-fym-1
title: Dataset: Woburn Organic Manuring Experiment organic manure chemical composition 1965-2019

description: Details of the amounts and chemical composition of the organic manures and other amendments applied to the Woburn Organic Manuring Experiment, 1965-2019. Organic manures (farmyard manure (FYM), peat, compost, straw, cover crops and green manure) were applied in three phases: 1966-1971; 1981-1986; 2003 onwards. Grass and grass/clover leys (short-term grassland) were also included as treatments 1965-1972; and 1979-1987. The leys were incorporated (ploughed in) at the end of each phase. Permanent grass/clover has been included as a treatment since 2003, but has not been incorporated in this phase of the experiment. Arable crops were grown in the intervening years to assess the effects of the different organic amendments. 


This dataset provides details of the amounts of the manures applied and of their chemical composition: % total N, P, K, Ca, Mg, Na and S, and the total amount of each element applied (kg/ha). %C data is available for FYM, and % organic matter in FYM, peat and straw, 1966-1971. %N data is available for the green manure, and grass and grass/clover leys sown in 1965 and incorporated in 1971/1972. Data is available for boron in FYM, peat and straw, 1966-1971, and trace elements in FYM and straw, 1981-1983 (Fe, Mn, Zn, Cu, Ni, Co, Cd and Pb). No data is available for the cover crops grown since 2003, or grass/clover sown in 1979 and 2003.


The FYM (25t/ha) supplies on average 189 kgN/ha, 42 kgP/ha and 215 kgK/ha; the straw (7.5t/ha) 37 kgN/ha, 4 kgP/ha and 67 kgK/ha. For comparison, the standard inorganic fertilizer treatments on the Woburn Organic Manuring experiment since 2003 supply 0-250 kgN/ha, 20 kgP/ha and 83 kgK/ha.
description: - **Total nitrogen** determined in FYM in fresh sample (not dried) at normal moisture content, by Kjeldahl digestion. 
 In other organic manures and amendments, determined in oven-dried samples, by Kjeldahl digestion, 1965-1986 and by combustion, based on the Dumas method, using the LECO combustion system since 2003. 
- **Total carbon** determined by combustion in oven-dry samples. 
- **Total P, K, Ca, Mg, Na and S and trace elements** determined in oven-dry samples by digestion with 6M HCl, the extracts analysed by ICP-OES. 
- **Boron** (1966-1971) measured colorimetrically, after dry ashing (Mattingly, 1974) . 
- **Organic matter** (1966-1971) measured by loss on ignition (Mattingly, 1974).
description: An Excel file with annual data, 1965-2019. Frictionless CSV files are also provided for users who prefer the CSV format.
description: - **Code Dg**: Farmyard manure (FYM) applied at 50t/ha 1966-1971 and 1981-1986
- **Code Dg10**: FYM applied at 10t/ha 2003 onwards
- **Code Dg25**: FYM applied at 25t/ha 2003 onwards
- **Code Pt**: Peat applied at 7.5t/ha 1966-1971 only
- **Code St**: Chopped cereal straw applied at 7.5t/ha for all three periods
- **Code Co**: Compost applied at 40t/ha 2003 onwards
- **Code Gm**: Green manure undersown to spring cereal, 1965-1971
- **Code CC**: Cover crop grown before spring crop, 2003 onwards
- **Code Lc**: Grass/clover ley. Grown for between six and eight years then incorporated, 1965-1972 and 1979-1987, sown 2003, not incorporated in this phase of the experiment
- **Code Ln**: Grass ley with nitrogen fertilizer. Grown for between six and eight years then incorporated, 1965-1972 and 1979-1987


**Organic matter** in peat, straw and FYM was measured 1966-1971. This was converted to %C assuming 58% C in organic matter. 

**Trace elements** (Fe, Mn, Zn, Cu, Ni, Co, Cd, Cr and Pb) were measured on FYM and straw applied 1981-1983. Two replicate samples (A and B) were taken from each sample for analysis. If the value was below the Limit of Detection of the equipment used, it is shown as LOD, and the actual LOD is listed in the fields_metadata under the appropriate trace element.
description: Early data from Mattingly (1974), Rothamsted Report for 1973, Table 2 and Appendix Table 2. Additional data from the Rothamsted Library Archive. 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. Data checked by Paul Poulton and Andy Gregory. 

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. Years quoted refer to the year of harvest (harvest year); the organic amendments were usually applied the previous autumn. 

In some years, two replicate samples, A and B, were taken. For the FYM, these were from the front and back of the trailer containing the FYM.