Future proofing a long-term agricultural experiment for decades to come: Relocation and redesign

Abstract

We took land encroachment for urban development that threatened a 60-year-old field experiment as an opportunity to transport and redesign an entire experiment to more effectively address contemporary challenges. The field experiment comprised long-term pH plots, established for agronomic demonstration in 1961, but used over the years for both applied and fundamental research. We redesigned the experimental layout to add strength to the statistical design through randomisation. Continuation and enrichment of the long-term pH experimental platform lends a unique resource for microbiome research per se. Here we have provided a rationale for why the decision was made to move the soils from the former Woodlands Field pH experiment. Moving soil on the scale of a field experiment requires costs and benefits to be weighed up in that the realisation of the transfer costs and the costs for the ongoing maintenance can outweigh the costs of a new experimental set up or indeed closing the experiment and walking away. It is important to recognise that much of the value is in assets that are not monetary. Considerations include the availability of a site suitable from a biophysical perspective but also considering ownership and future access. The topsoil (0–20 cm to plough depth) was moved to a new location in a similar environment and within the same soil association. The soil was disturbed under very dry conditions and placed back into the earth in the new location within 90 minutes, and thus as near to normal cultivation as possible. Additional plots were added to the experiment that will be amended to the pH treatments in the long-term experiment providing an exciting opportunity to assess how soil microbial communities change over time. Soil samples taken 2 years after the relocation of the soils indicate that the soil pH gradient (4.5–7.5) has been maintained. Safeguarding this long-term resource on soil pH helps us to predict the impacts of changed practice with regard to liming on productivity and also to address wider contemporary and future issues surrounding net zero, food security and soil protection.