42 Pasture Problems 



and clovers or with a more complete mixture that all the stages in 

 stabihsation can be best followed. 



It is not necessary for the purpose of tracing the main features in 

 the competition of sown with un-sown species to difEerentiate between 

 all the types of grassland previously discussed. It will be sufficient 

 to deal with (A) Fields at and above 600', which may occur on either 

 shales or on clay ; (B) Fields below 600' on shales ; and (C) Fields below 

 300' on well-drained alluvia and on glacial gravel. 



A. Fields above 600'. 



The herbage ultimately covering such fields would depend upon the 

 soil. If it was derived from shales then it would become a heath fescue 

 pasture; or, if it was a drift clay, then a Molinia or Nardus pasture 

 would finally result. The early stages are, however, very similar in 

 both cases, and for the sake of bre\'ity are classed together in some 

 of the tables given. It will be convenient to deal firstly with fields sown 

 only with perennial rye grass, red clover and trefoil ; and secondly 

 with fields sown with a more complete mixture. 



Fields sown ivith rye grass, red clover and trefoil, only. 



Over fifty fields have been analysed which were sown with the 

 above simple mixture; some of the fields have received farmyard 

 manure, some superphosphate, and some basic slag. In most cases 

 hay was taken for the first one to four or six years ; and the fields subse- 

 quently grazed. The results obtained are presented in a generalised 

 form in Table II ; the percentage range of occurrence for each species 

 being given in terms of percentage frequency. Some further details 

 are given in the footnotes directly under the table. 



The chief points to be noted from these results, and from the 

 data presented in subsequent tables, will be discussed under the 

 several species in the summary at the end of this section. 



Fields sown with a more complete mixture. 



Two interesting sets of data are available for fields sown with com- 

 paratively complete mixtures. The fields were 650'-700' above sea 

 level on thin soil over shale; in both cases farmyard and phosphatic 

 manures were freely applied. In one case (see Table III) hay was 

 taken for the first two years — the field being subsequently used only 



