Photograph of a sample of grasses in plot 5 that have been treated with Ammonia Salts at Rothamsted in the mid 20th century.

Photograph of a plot of grasses with full minerals after nitrate at Rothamsted, [England] in the early/mid 20th century.

Photograph of a plot of land in a small box that was tested with full minerals and ammonium salts at Rothamsted in England in the early 20th century.

Photograph of a plot of land in a small box that was tested with full minerals and nitrate of soda at Rothamsted in England in the early 20th century.

Graph illustrating the growth of wheat at Rothamsted over a period of 13 years with increasing amounts of nitrogenous manure from the early/mid 20th century.

Image of a table showing the development of the growth of wheat in nitrogen manure at Rothamsted in 1903.

Informational graph on the total available plant food in soil compared with that removed in wheat crop at Broadback Field, Rothamsted, [England] in the early/mid 20th century.

Photograph of the buildings of Rothamsted [Experimental Station], [Harpenden, Hertfordshire, England] in the early 20th century.

Image of a table summarizing the measurements of sulphuric acid and chlorine in rain-water that was collected at Rothamsted between 1881 and 1887.

Table of information on the amount of nitrogen and chlorine in Rothamsted Station's rain by monthly averages over a 15 year period from 1889 to 1903.