Broadbalk experiment

In news: It is the world’s longest running farm study.

About the experiment-

• The field in Hertfordshire county of southern England has been under continuous scientific experiments for the past 178 years.
• Scientists have been sowing wheat on the field, named Broadbalk, every year since 1843 to understand how to use fertilisers to improve crop yield.
• The research was started by agricultural scientist John Bennet Lawes and chemist Joseph Henry Gilbert under the Rothamsted Research institution. 
• The aim of the experiment is to test the effects of different organic and inorganic fertilisers on soil fertility and study the optimum nutrition requirements to improve crop yield.
• The land was divided into 19 strips of wheat field, each 300 metres long and 6 m wide.
• To test the benefits of different combinations, some strips received inorganic fertilisers, some organic and some others a combination of both. 
• One strip was left received neither of these. 
• After 175 years of study, the scientists have found that yields from the section where wheat was grown with a two-year break, were higher than from sections where wheat was grown continuously. 
• The use of organic manure had increased the soil organic matter content on some plots.
• The highest average yield was in wheat treated with N6 fertiliser, grown in both continuous and rotational manner.

There is little benefit for farmers using fertilizers with such high levels of nitrogen.