Long-term experiments at Rothamsted Research, Harpenden, UK.

It is 1846. Soil and plant samples are meticulously collected and stored at the archive at Rothamsted Research, Harpenden, Herts. about half an hour north of London by train (see picture on the right). These samples are part of the long-term experiments that started in Rothamsted more than 150 years ago. The samples have been taken from the various treatments that are part of the classical and long-term experiments, which continue to be conducted at Rothamsted.

IPI Coordinators gathered at Rothamsted Research this spring, to learn more about the long-term experiments.

"...Between 1843 and 1856, Lawes and Gilbert started nine long-term field experiments, of which they abandoned only one, in 1878. Some treatments were changed during the first few years and, later, further changes were made to answer specific questions raised by the results... Their main objects were to measure the effects on crop yields of inorganic compounds containing nitrogen, phosphorus, potassium, sodium and magnesium (N, P, K, Na and Mg), elements known to occur in considerable amounts in crops and farmyard manure (FYM), but whose separate actions as plant nutrients had not been studied systematically."

The visit to Rothamsted Research was an excellent opportunity for IPI Coordinators to see the set-up of the experiments and learn of the assumptions and management of these through the years. The results of the experiments demonstrate the impact of long-term agricultural activity with various fertilization and management treatments on soil quality and fertility, changes in soil's chemical properties (e.g. pH), biodiversity, and more.

"It is a testament to the foresight of Sir John Lawes and Sir Henry Gilbert, as well as others who have come after them, that experiments established decades ago continue to reveal new insights and important findings of relevance to today's agriculture and its interactions with our ever-changing environment" (Crute, 2006).

In a presentation titled 'Rothamsted Research and Potassium', A.E. Johnston presented findings on leaching of potassium below the plough layer, the well-established relationship between soluble water and exchangeable K and K concentration in plant's tissues. The uptake curves of potassium by barley, the effect of potassium on sugar yield of sugar-beet crop and other crops, and finally the development of conceptual framework for potassium in soil were also presented.

See more on the long-term experiments of Rothamsted research at:

• http://www.rothamsted.ac.uk/resources/ExperimentsGuide.html; (Guide to the classical and other long-term experiments, datasets and sample archive, 2006. A publication of Rothamstead Research, www.rothamsted.ac.uk).
• http://www.agriculture.purdue.edu/broadbalk/.

Note: All the quotations made in this report are taken from http://www.rothamsted.ac.uk/resources/ExperimentsGuide.html.