52 



EFFECT OF PHOSPHATES 



disappeared, the improvement in the grasses has succeeded in reducing 

 the amount of weeds to about one-third of that present in the hay 

 from the untreated plots. The main points of difference are illustrated 

 in Figs. 7 and 8. 



w 



"8 







I 

 I 



FIG. 8. Botanical composition of the Hay, by weight, at Tysea Hill. 

 Season, 1919. Soil Boulder clay. 



1, Basic Bessemer slag. 2, Gafsa rock phosphate. 3, Untreated. 4, Open 

 hearth (fluorspar) basic slag. 5, Open hearth (high soluble) basic slag 1. 

 6. Open hearth (high soluble) basic slag 2. 



TABLE XXIV. PERCENTAGE OF GROUND SPACE OCCUPIED BY THE 

 VEGETATION AT TYSEA HILL AND MARTIN'S HEARNE 



The aftermath on both sets of plots was grazed by cattle, and 

 during the first week of October 1919 a determination of the ground 

 space occupied by the various species was made, and the results are 

 set out in Table XXIV. 



The clover had not reappeared at either centre in spite of the 

 favourable climatic conditions, and although the treated plots could 

 be distinguished from the unmanured more than a mile away through- 



