244 



Improvement of Grazed Pastitrbs. 



[June, 



It would appear from the figures in this table that the 

 balance of the herbage on the slag and Gafsa plots was so 

 upset that it was unable immediately to return to its original 

 state, but immediate reversion was possible on the super- 

 phosphate plot when the effects of the manure w^ere exhausted. 



The effects of slag and of Gafsa phosphate are particularly 

 marked upon some plants. It is curious to note that Agrostis 

 spp. were much increased even by the fourth summer, when 

 the plots were in excellent condition, w^hile by the sixth 

 summer there was a further increase, although the plots were 

 then in a very poor condition. Some of the other plots showed 

 very little change or decrease by the fourth summer, and, 

 except on the superphosphate with ground lime plot, the 

 development of Agrostis was not far from normal in the sixth 

 summer. Festuca ovina was even more markedly affected by 

 slag and by Gafsa phosphate, but on the other plots it suffered 

 relatively little. There was a marked decrease of Molinia on 

 the most improved plots, but relatively little on the others. 



From these results, it would appear that, under the con- 

 ditions of the experiment, (1) a marked improvement may be 

 accompanied by such a change in the botanical composition 

 of the herbage that, when the direct effect of the manure has 

 been exhausted, the herbage may become even poorer than 

 it was originally; (2) an increase in Agrostis spp. ma}^ accom- 

 pany a marked improvement; (3) a decrease of Festuca ovina 

 may also occur when an improvement takes place, and, in 

 extreme cases, may almost disappear as a result of treatment 

 which has given a great improvement; (4) an increase in 

 Trifolium repens accompanies an improvement, while a decrease 

 accompanies a deterioration ; (5) Sagina 'procumhens shows 

 an increase with improvement, and may maintain or even 

 improve its increase Vv^ith the deterioration which follows 

 improvement, if the general balance has been so apset that 

 direct reversion to original condition is not possible. 



Centre'C : Ffyddion, near Caerwys, Flintshire 



Field: Very old pasture, continuously grazed, rather flat, but 



naturally well-drained. 

 Soil : Mostly rather heavy loam on clay drift over limestone. 

 Altitude: About 650 feet. 

 Main/all : About 40 inches. 



The plots at this centre were also examined by the Percentage 

 Frequency method in the fourth summer afif^r the application 

 of the manures. Part of Plot YII was on rather lighter soil 

 than the other plots, and the results obtained are not, there- 



