Wikipedia reveals that ..” The Rothamsted Experimental Station was founded in 1843 by John Bennet Lawes, a noted Victorian era entrepreneur and scientist who had founded one of the first artificial fertilizer manufacturing factories in 1842, on his 16th century estate, Rothamsted Manor, to investigate the impact of inorganic and organic fertilizers on crop yield.”
The Broadback Field experiment started in 1843. Organic school called this the home of the NPK school.
The Secretary’s letter #21 of 1949 has a paragraph called Lessons from the Drought
“It is not often that Rothamsted is being quoted in support of the use of humus. The weekly News Service of the Ministry of Agriculture, No 514, of 26th July 1949 discussed Lessons from the drought, and said in the course of the informative article; “… In general, the best safeguard is an adequate supply of humus. It holds water better than soil. Plots at Rothamsted treated regularly with farmyard manure contain 3 to 4% more water than plots receiving manure containing no humus. And of course, every gardener knows how much better are his potatoes, beans, peas, etc if rotted organic matter is underneath them …”