54 EFFECT OF PHOSPHATES 



A comparison of Tables XXV and XXVI brings out several points 

 of considerable interest. In the first place the all but complete dis- 

 appearance of clover from the herbage at Martin's Hearne and Tysea 

 Hill during the dry season of 1919, and the return of the clover at 

 Martin's Hearne but not at Tysea Hill during the moist favourable 

 season of 1920 is curious. Secondly, it will be noted that during the 

 dry season of 1919 weeds formed about 30 % of the small crop on 

 the untreated plot at both centres. In 1920 weeds still formed about 

 30 % of the crop by weight at Martin's Hearne, but at Tysea Hill 

 the crop on the untreated plot was a heavy one and the hay on this 

 plot was as free from weeds as on any of the treated plots. 



TABLE XXVII. BOTANICAL COMPOSITION OF THE HAY BY WEIGHT 

 AT LAMBOTJKNE END (LONDON CLAY) 



Sample taken: July 17th, 1919. Manures sown: Jan. 4th, 1919 



Composition of the grasses by weight 



Lambourne End (London clay). The botanical composition of 

 the hay at Lambourne End is shown in Table XXVII. As will 

 be seen from this table, the phosphates were sown six months 

 before the plots were cut. The season (1919) was a dry one, and the 

 phosphates were without any appreciable effect on the clovers, which 

 could therefore not act as an intermediary in encouraging the growth 

 of the grasses. Nevertheless the basic slag plots yielded almost twice 

 the crop secured on the unmanured plot, a result which appears to 

 indicate that phosphates have a direct and not an indirect action on 

 the grasses, and that it is quite possible to obtain a specific and marked 

 response to phosphates on pastures where clover plants are absent. 



