280 EXPERIMENTAL STATIONS — EEPOET FOR 1879. 



On Harelaw the effect of applying dissolved phosphates has 

 been to increase the percentage of ash considerably, and this 

 increase is seen to be quite regular over all the plots. At 

 Pumpherston the results seem to point in an opposite direction, 

 the average amount of ash in the undissolved being slightly over 

 that of the dissolved phosphate plots. 



On comparing this table with that which exhibits the amounts 

 of water contained in the crops (page 276), it will be seen that 

 the percentage of ash varies very regularly with the percentage of 

 water contained in the bulbs, the rule being that the higher the 

 percentage of water the higher the percentage of ash. There 

 seems to be an intimate relation between these two constituents. 

 It would naturally l)e expected that plants to whose roots dis- 

 solved minerals were applied should be able to absorb more 

 mineral matter than others, but why they should also absorb 

 more water is not quite so apparent. The explanation is pro- 

 bably to be found in osmotic action. The rootlets of plants con- 

 sist of cells and vessels containing albumenoid matter, and whose 

 delicate walls constitute a fine membrane, permitting of the easy 

 diffusion into them of the crystalloid salts surrounding them in 

 the soil, and it is in great measure to this endosmotic action that 

 the absorption and flow of sap in plants has been ascribed. It 

 follows from this that the amount of water taken up by the 

 roots of plants will be greater in proportion as there is present 

 around their rootlets dilute solutions of crystalloid substances, 

 such as are contained in dissolved manures, and it is probable 

 that the higher percentage of water in the turnips grown with 

 dissolved phosphates is due to this cause. If this explanation is 

 correct we should expect to find that an increase in the propor- 

 tion of ash should l)e accompanied by an increase in the propor- 

 tion of water. 



At both stations the amount of mineral matter abstracted from 

 the soil per acre is greater where the dissolved phosphates have 

 been applied, and it would thus appear that the dissolving of 

 phosphates enables the plant to make better use of the mineral 

 food contained in the soil or supplied to it in the manure, and 

 also til at farmyard manure, made from the consumption 

 of turnips grown with dissolved phosphates, will be richer in 

 mineral plant food than that made from the consumption of 

 turnips to which undissolved manures had been applied. 



We come next to consider the effect produced by various forms 

 of manure upon the amount of albumenoid matter contained in 

 turnips. Tins is an important inquiry, and one which will 

 receive careful attention in future experiments at our stations. 

 Albumenoid matter is present in small amount in turnips, but 

 it is the constituent of most importance in determining their 

 feeding value, and anything which could be found to increase the 



