328 The Wolmrn Pot-Culture E.rperiments, 1910-11-12. 



I'JOG crop, and which are similar to those obtained in 1907 

 from the respective pots (a), (6), (c), and {d) of Plate 9. 



Yet another feature was prominently brought forward, viz., 

 that the grain altered its character accordii g as more and more 

 magnesia was present in the soil, and starting with the ordinary 

 " Square Head's Master " wheat (a " starchy " wheat, as it would 

 be termed), the grain obtained when magnesia had been added 

 was found to have become what would be called a " hard " 

 wheat, and the grains, on being cut across, exhibited a distinctly 

 glutinous appearance, whereas the produce of the natural soil 

 when cut across was quite " starchy." This change was even 

 more emphasised in the succeeding lots where more magnesia 

 had been used, though the grain itself was much more shrivelled. 

 Analyses made subsequently showed that the grain grown with 

 magnesia gave increasingly higher nitrogen contents as magneeia 

 was added. 



These observations were repeated with the same general 

 results, and they were then extended to barley. Also different 

 forms of magnesia were tried in 1908 (see Journal R.A.S.E., 

 Vol. 70, 1909, pp. 391-3). In 1909 ground limestone was tried 

 in comparison with burnt lime, as also magnesian limestone. 

 The addition of magnesia to the soil was tried with red clover 

 and beans, but without showing any benefit. Lastly, in this 

 year there was begun a new series of experiments which 

 formed a complement to the earlier ones. Instead of a soil 

 poor in magnesia, one naturally richer in magnesia than in lime 

 was taken, and this was treated with increasing quantities of 

 lime. The account of these experiments of 1909 is given in 

 Journal R.A.S.E., Vol. 71, 1910, pp. 346-9. 



Up to this point all the work done had been on the small, or 

 " pot-culture " scale, and it had not been possible to obtain 

 sufficient grain to test the question of " strength " as understood 

 by the miller and baker. The most that could be done was to 

 determine the nitrogen contents of the grain. 



Later on — as will be recorded — the experiment was carried 

 out on a larger scale. The general conclusions to be drawn at 

 this stage were : — 



1. That the addition of magnesia to a soil poor in this 

 constituent will, as regards a corn crop, be attended with benefit 

 so long as the amount of magnesia does not exceed that of lime, 

 but that if the magnesia be in excess of the lime there will be 

 diminution of produce. 



2. That the influence of magnesia shows itself in a prolong- 

 ing of the period of incubation and in later ripening of the 

 crop, in greater leaf development and greener foliage, and also 

 in a shortening of the straw. 



