SECTIONAL TRANSACTIONS.— K. 431 



affect the flora so profoundly that initially different floras kept under the 

 same conditions for a few years and managed in the same way tend to become 

 indistinguishable. Grass land can always be improved by improving its 

 management so long as the desirable plants are already there. But if they 

 are not, the grass land must be broken up and reseeded. 



There are many varieties and strains of the same species of grass, and 

 also of the micro-organisms associated with the nodules of leguminous plants. 

 These also form part of the grass problem. 



Dr. Winifred E. Brenchley. — The ultimate composition of the herbage 

 from various seeds mixtures (10.20). 



Sawyer's Field at Rothamsted was laid down to grass in 1928, being sown 

 with six different mixtures, ranging from simple to complex. The area was 

 grazed till 1935, and cut for hay in 1936. Estimations of herbage composi- 

 tion have been made regularly, the methods used being specially adapted to 

 meet the difficulties that arose as the sward became established. At first 

 the botanical composition of the herbage bore some relation to the seeds 

 mixture sown, but this soon disappeared and a general levelling up occurred 

 on all the plots. Clovers and grasses were of almost equal importance until 

 the drought of 1933, which killed out most of the clover, its place being 

 largely taken by grass. A certain increase of wild white clover has since 

 occurred, but the leguminous species have failed to regain their original 

 importance. 



Summarising the present position, rye grass (Lolium spp.) has assumed and 

 retained a dominant position, the Italian variety being particularly persistent. 

 Cocksfoot (Dactylis glomerata) has spread rapidly, regardless of the amount 

 sown, whereas rough-stalked meadow grass {Poa trivialis) was slow in be- 

 coming established. All the clovers have disappeared except the wild white, 

 which shows marked seasonal variations, being specially influenced by rain- 

 fall. In general, comparatively little difference is now obvious between the 

 herbage of any of the plots, regardless of the type of seeds mixture sown. 



Mr. William Davies. — Present-day concepts of grassland improve- 

 ment (10.50). 



The principles of grassland improvement may be grouped as follows : 

 (i) the botanical composition of the grassland ; (a) pasture and stock manage- 

 ment ; (3) soil fertility and the means of grading up that fertility. These 

 groups cannot be discussed singly without reference to the others because 

 of their interdependence. Whatever is done to grassland is reflected upon 

 that grassland as a whole. Thus alteration in soil fertility or a modification 

 of grazing practice is bound sooner or later to be reflected in the botanical 

 composition of the sward. 



The compounding of seeds mixtures is discussed, with particular reference 

 to simple and complex mixtures ; also the place of the grass and the legume 

 in pasture improvement, sward production and the maintenance of botanical 

 composition. The relationship of botanical composition to the productivity 

 and the economic value of pastures. 



Strain within the species in our common grasses and clovers and methods 

 of evaluation of strains bred for economic purposes. 



The influence of sharply contrasting systems of management upon the 

 botanical composition and the yield of pastures. The management of young 

 leys, temporary pastures and permanent pastures. Management in relatioii 

 to soil fertility and in relation to the manuring of grassland. 



