CONTRIBUTIONS FROM THE WISLEY LABORATORY. 313 



the manganese is, however, a side issue and may be ignored. If we 

 leave out the plots which received manganese we get the following 

 comparisons, the two plots compared having been weighed on the 

 same day : — 





Weight of 

 thinnings. 



Weight of 

 thinnings. 



Weight of 

 thinnings. 



Untreated ..... 

 Dressed with bacterized peat 



4,740 grms. 



5.025 „ 



5,724 grms. 



7.309 „ 



9,405 grms. 

 8,835 „ 



The plants, after thinning, were allowed to grow on, with the necessary 

 attention to hoeing, and were all pulled, counted, and weighed on 

 July 29, with the following results : — 



Plot. 



Dressing received. 



No. of 

 Plants. 



Gross weight. 



Average weight. 



Tops. 



Roots. 



Total. 



Tops. 



Roots. 



Total. 









Lb. 



Lb. 



Lb. 



Oz. 



Oz. 



Oz. 



I 



Nothing . 



263 



81-5 



42 



123-5 



4'9 



2-5 



7-4 



2 



Bacterized peat, 11 lb. 



261 



96 75 



39-25 



136 



5-9 



24 



8-3 



3 



Bacterized peat, 11 lb., 



207 



8975 



44-25 



134 



6-9 



3-4 



10-3 





+ sulphate of manganese 













4 



Nothing 



239 



815 



46-5 



128 



5-4 



31 



8-5 



5 



Bacterized peat, 11 lb. 



221 



89-25 



45-75 



135 



6-5 



33 



9-8 



6 



Bacterized peat, 11 lb., 



















+ sulphate of manganese 



197 



79-25 



39 



Il8-2 5 



6-4 



31 



95 



7 



Nothing . 



186 



53-75 



21-75 



75-5 



4-6 



i-9 



6-5 



8 



Bacterized peat, 11 lb. 



180 



54-5 



22 75 



77-25 



4-8 



2 



6-8 



9 



Bacterized peat, 11 lb., 

















+ sulphate of manganese 



185 



61 



29 



90 



52 



2-5 



7-7 



The difference in the number of plants on the rows was due for the 

 most part to the death of plants from various causes, and partly 

 probably to the plants in the last set of three having been somewhat 

 larger when they were thinned. Consideration of these figures shows 

 that in all cases there was a slight increase in the average weight 

 of the whole plant on the plots treated with bacterized peat, and this 

 was generally increased where both peat and manganese sulphate 

 had been added. The increase was more, however, in the tops than 

 in the roots where peat alone was used, as the following figures, 

 showing the relative weight of tops to roots, demonstrate : — 





Plot. 



Roots. 



Tops. 



Average of 

 three plots. 



Untreated soil ..... 



I 



100 : 



194 





>> >> ..... 



4 



100 : 



175 



205 



>> >> ..... 



7 



100 : 



247 





Dressed with bacterized peat 



: 



100 : 



246 







i 



100 



195 



227 







100 



239 





Dressed with bacterized peat and man- 



3 



100 



202 





ganese ...... 



6 



100 



203 



205 



>> „ . . . . 



9 



100 



2IO 





