THE ESSEX EXPERIMENTS 



25 



when the harvest was again late, and the season exceptionally moist, 

 the advantage was once more with the rock phosphates. In each of 

 the four years the open hearth (fluorspar) basic slag (plot 1) was 

 considerably less effective than the other types of phosphate. 



The dense growth of clover which covered the plots in 1918 failed 

 to make an appearance in 1919 and all the plots were practically 



TABLE X. WEIGHT OF HAY AT MARTIN'S HEARNE FARM 

 Manures sown: February 20th, 1917 



* Applied at the rate of 10 loads per acre in the autumn of 1919. 



30 



20 



10 



123456 

 FIG. 2. Yield of Hay (average of 4 years) from the various Phosphate Plots 

 at Martin's Hearne. Soil Boulder clay. 



1, Untreated. 2, Open hearth (fluorspar) basic slag. 3, Egyptian phosphate. 

 4, Algerian phosphate. 5, Gafsa phosphate. 6, Open hearth (high sol.) basic slag. 



