240 



Improvement of Grazed Pastures. 



improvement, and the chief botanical result was a distinct 

 increase, both in number and vigour, of Jiincns suhnodulosn^, 

 following the application of basic slag, superphosphate and 

 superphosphate with ground lime. The most interesting 

 feature of this experiment, however, was that ground Gafsa 

 phosphate had no effect whatever. 



At the other three centres, very marked results w^ere 

 obtained, but, unfortunately, owing to some doubts as to the 

 uniformity of the soil, three of the plots at Centre A and one 

 at Centre C have been ruled out. 



All the results given here were obtained by the Percentage 

 Frequency method. This method has the effect in some cases 

 of obscuring some important features, particularly the effect 

 of treatment upon the density of the herbage as revealed 

 by the number of plant units per unit area. For this reason, 

 aggregate results are given in terms both of plant units per 

 unit area, and percentage frequency, the unit area selected 

 being 36 sq. in. To give detailed analyses would mean very 

 long tables, and although these would be interesting, the 

 results for many plants occurring only in relatively small 

 quantities would not be sufficiently definite to be of much 

 value. Only the most important plants are. therefore, included 

 in the detailed results. 



The Effect of Potash. — At none of the centres where 

 botanical analyses were made w^as there any indication that 

 potash had any appreciable effect. At another centre, how- 

 ever, on well-drained, deep, acid peat, it had a marked effect. 

 On the " No manure " plot, it had the effect of increasing 

 Knapweed (Centaurea nigra) in a very conspicuous manner, 

 but this was not seen where the potash was used with other 

 manures. The greatest improving effect was obtained when 

 potash was used with superphosphate and ground lime, but it 

 was also clearly seen on the basic slag. Gafsa phosphate, and 

 superphosphate plots. 



No marked difference could be seen between the basic slag 

 and Gafsa plots, although White Clover was more developed 

 on the latter. Both were obviously superior to the superphos- 

 phate plot, which, however, showed considerable improvement 

 over the unmanured plot. 



All three plots showed a marked increase in the number of 

 plant units per unit area. It is interesting to note (Table II) 

 that the number of grass unit? increased equally on the basic 

 si a;? and Gafsa plots. There was a considerably greater 

 increase in grass units on the superphosphate plot, but the 



