632 SECTIONAL TRANSACTIONS.— M. 



Mr. Donald MacKelvie. — Breeding of Potatoes. 



Mr. M. M. MoNiE. — The Soils of West Stirlingshire. 



Friday, September 7. 



Joint Discussion with Section I (q.v.) on Lactation and Nutritiona 

 Factors allied thereto. 



Kt. Hon. Lord Bledisloe, K.B.E. — Grassland Improvement. 



Need for better grassland farming with temporary decay of arable husbandry. 



Pasture a crop. 



Applicability of Dr. Warmbole's methods to British conditions. 



Protein in young grasses comparable with that in clover. 



Outline of System. 



(1) Cultural treatment; (2) Repeated fertihser dressings; (3) Close rotational 

 grazing period lengthened. Stock carrying capacity increased. Not ' Three acres 

 and a cow,' but ' Three cows and an acre.' 



Leafy indigenous strains of herbage respond most to nitrogenous fertilisers. 

 Hardening efEect of potash. 



Mineral content of pasture adequate if intensively treated. Effect on milk 

 yields. 



Size of fields for rotational grazing unimportant. Importance of mowing machine. 



Intensive system specially applicable to Small Holdings. Output of British 

 Small Holdings far too small. 



Economic justification of Intensive System. 



Afternoon. 



Dr. D. N. McArthur. — Mineral Metabolism of Swedes. 



The primary object of the investigation was the study of the efEect of a phosphatio 

 fertiliser upon the metabolism of the swede. The phosphate used was a sihcophosphate 

 whose molecular constitution was determined by the co-ordination of metallographic, 

 petrographic and chemical examinations. 



The variety of swede used was ' Scotia ' — chosen because it showed uniformity 

 in great measure. The plants were grown on two plots and samples were taken 

 regularly throughout the summer and winter months. At each samphng, fifty plants 

 were taken from each plot and from these representative portions of bulb and leaf 

 were drawn. Between June and September the samphng was conducted at intervals 

 of fourteen days and thereafter at intervals of thirty days. The ' control plot ' 

 received no manurial treatment, whUe the ' manured plot ' received an application of 

 the sihcophosphate. 



The percentage of dry matter was determined in each sample and subsequently 

 the weights of dry matter in the fifty plants (bulbs and leaves calculated separately) 

 were calculated. The dry matter obtained at each samphng was analysed for calcium, 

 phosphorus, nitrogen and silica. From the percentages obtained the molecular ratios 

 were calculated, taking lime as unity in all cases. 



During the first fifty days of growth the absorption of calcium, phosphorus and 

 nitrogen was slow, but rapidly increased during the following ten days. The rates of 

 absorption of calcium and nitrogen were similar but phosphorus was absorbed at a 

 slower rate during the first sixty days. Each of the mineral elements in the leaves, 

 except siUcon, was translocated to the bulb at the end of the first year's growth. The 

 calcium was returned earher than the phosphorus but was also translocated back to 

 the leaves at an earlier date in the second year's growth. 



The metabohsm of calcium in the leaf appears to be a function of the nitrogen 

 metabolism or vice versa. 



The increase in weight of the bulb during November and December is largely due 

 to an increased absorption of water, and evidence was obtained to support the 



