522 Experiments with Phosphates a.nd Stags. [Sept., 



for the five years 1917 to 1921 are shown in Table 2 and are 

 illustrated in Fig. 1 : — 



Table 2. — Weight of Hay at Martins Hearne Farm. 

 Manures sown : 20th February, 1917. 



Plots 

 I acre 



Manure 

 200 lb. P2O, per acre 



Citric 

 solubility 

 of phos- 

 phate, 

 per cent. 



Hay (in cwt. per aere). 



1917 



1918 



Open hearth (fluorspar) 



basic slag 



Open hearth basic slag ... 

 No manure 



Gafsa rock phosphate ... 

 Egyptian rock phosphate 

 Algerian ., ., 

 Farmyard manure* 



20-1 

 91-2 



38-6 

 35-0 

 35-7 



Kainfall, May 1st till 

 harvest (in inches) ... 

 Plots cut 



23 

 30-4 

 U-3 

 23-8 



22- 8 



23- 2 



28-6 

 33-4 

 23-4 

 38-6 

 35-9 

 35-0 



1919 



1920 



1921 



16-4 

 27-0 

 10-4 

 24-8 

 21-9 

 21-0 



6-27 

 July 

 23 



11-51 

 Aug. 

 10 



2-85 

 July 

 9 - 



28- 4 

 31-9 



23-0 

 35-2 



29- 

 34-6 

 403 



9-9 

 13-4 



9-4 

 15-6 

 10-8 

 12-7 

 15'5 



Average 

 5 years 



21-3 

 27-2 

 16-1 

 27-6 



24- 1 



25- 3 



8-3- 



Aug 

 9 



2-44 



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



r 



4-0 



^0 



20 



1 . 



o 



o 

 U 



10 H 







4 



5 



Fig. 1. — Yield of Hay (average of 4 years) from the various Phosphate Plots at Martins Hearne. 

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

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



The improvement which followed the application of the 

 various phosphates was very marked indeed. During 1917 a 

 mat of wild white and red clover began to cover the plots, and 

 during 1918 it w^as so thick on some plots as almost to exclude 

 the grasses. 



As will be seen from Table 2 the high soluble slag proved 

 considerably more effective than the open hearth fluorspar slag 

 (low soluble) throughout the whole course of the experiment. 



