0. Crowtiier and a. G. Ruston 201 



Of the plots receiving "artificials"' only (Plots 7-12), the nitrate 

 plots (7, 9, 11) have, in the main, kept up the relative standard of 

 fertility established at the start, whilst the ammonia plots (8, 10, 12) 

 all show signs of losing ground. This is notably the case with Plot 12 

 (ammonia alone) which in six years of the series has given yields no 

 greater than those obtained from the adjoining unmanured Plot 13. 



Effects upon Character of Herbage. 



It is now a familiar observation that the continued manuring of 

 grass-land may produce marked changes in the character of the 

 herbage^. That this has been the case in the experiments here under 

 review is obvious to the eye and is clearly defined in the results of 

 botanical surveys of the plots that have been made from time to time. 



The first of these was made by J. N. Cameron^ in May and June 

 1906, the method adopted being to take four specimen turves from 

 each plot, tease out the different plants, sort out into species and weigh 

 after removal of the roots. The weights were then calculated as per- 

 centages of the total herbage. The results were also checked by a 

 rougher examination of the herbage of much larger areas of the plots. 

 The great disadvantage of the method lay in the extreme difficulty 

 of getting turves really representative of the whole plot, since the 

 grasses tend to grow in patches. 



A further botanical analysis of some of the plots (Nos. 1, 2, 3, 0, 

 7, 9, 11, 12) was made in 1909 by J. R. Bond^, the samples this time 

 being taken from the cut grass lying in the swaths immediately after 

 mowing (July 22). Portions were taken from various parts of each 

 swath, and then the whole combined sample from each plot, weighing 

 several pounds, was dried, separated into its constituent species, and 

 these weighed. 



In order to complete the records the plots not dealt with by Bond 

 were sampled by one of us in July 1911 and dealt with on precisely 

 the same lines. Further analyses of some of the plots were made in 

 1914. 



In comparing the results of the three sets of observations it must 

 be borne in mind that the quantitative distribution of the various 

 species that compose the flora of a meadow may vary greatly from 



1 Cf. Stapledon, This Journal, VI. 499. 



^ Results? embodied in thesis submitted at Final B.Sc. Examination. 1907. 

 = Results embodied in thesis submitted at Final B.Sc. Examination, 1910. See also 

 "Guide to Experiments at Manor Farm, Garforth," 1914, pp. 6, 7. 



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