Farmers in the region are continuing to benefit from the evidence and insights gained from some of the longest-running agricultural research trials in the world. TMAF is supporting the management by NIAB of an important field experiment that has been running for well over a century.
1978
1978
Saxmundham in 1978
(credit: Ed Brown)
1980
1980
Saxmundham in 1980
(credit: Ed Brown)
1986
1986
Saxmundham in 1986
(credit: Ed Brown)
2023
2023
Saxmundham in 2023
The Saxmundham Experimental site was set up in 1899 by East Suffolk County Council to investigate how, with a typical Norfolk four-course rotation, crops respond to the relatively new technology of mineral fertilisers compared to more traditional methods of the day using farmyard manures.
The site has been run by various organisations in its lifetime including, for a large part, by Rothamsted Research. More on the history and historic results can be found on the e-RA Rothamsted archive website.
Trial future secure with TMAF
In 2015, after the site’s future had been in doubt and research had been discontinued for a short period, TMAF agreed to a long-term lease from Rothamsted. Since then, the site and investigation have been managed by NIAB and the long-term treatments and measurements reinstated.
Continuing tradition with some modern additions
The experiment’s aim has remained consistent over the last 120 years: to measure the response in crop and soil properties from the application of mineral phosphate and potassium fertilisers compared with manures and organic amendments. Many of the plots have received the same treatments since 1899 while some newer treatments more relevant to modern nutrient management were introduced in 2019.
Treatments on trial
The current treatment list and rationale are described in the table below.
| Treatment | Annual application | Target P | Target K |
|---|---|---|---|
| Untreated (Unt) | - | 0 | 0 |
| Farmyard manure (FYM) | 25 t/ha | 2 | 2+Low |
| Green Waste Compost (GWC) | ~18 t/ha (dose to match FYM organic matter additions) | 1 | 2+ |
| Foliar | 4 applications of Folex P (15 l/ha, 14%N, 46% P2O5) | 0 | 2+ |
| P | P2O5 | 2 | 2+ |
| K | K2O | 0 | 2+ |
| PK | P2O5 + K2O | 2 | 2+ |
| Low P+K | P2O5 + K2O | 1 | 2+ |
Results to date
Figures 1 and 2 show the soil P and soil organic matter results since treatment updates in 2019. Full annual results can be found in the annual reports.
In summary, most treatments are at their target indices for P with the P, PK and FYM plots Index 2 and above with K and Untreated between Index 0 and 1. In 2022 the GWK and PLK plots were at their target indices 1.
As the soils at Saxmundham are naturally K-releasing, all plots are an index 2- and above for soil K and only limited crop response to K has been recorded.
Soil organic matter is significantly higher in the FYM plots compared to all other treatments. Although FYM plots only record a 0.8% increase compared to PK, it is important to put this into context. This is a 19% relative increase and assuming a bulk density of 1.2 g/cm3 in 20 cm of soil it equates to 19.2 t of organic matter more per ha.
After 120 years of FYM applications, the soil has likely reached a new equilibrium.
External links
The Saxmundham Experimental Site research is also listed at:
- e-RA Rothamsted Archive
e-RA provides a permanent managed database for secure storage of data from the Long-term Experiments at Rothamsted, Woburn, Brooms Barn, and Saxmundham. - Global Long Term Trials Network (GLTEN)
The GLTEN is network of long-term agricultural experiments and associated researchers spanning 6 continents.