The Ecology of Calluna vulgaris. 
C.—Chemical Analysis of 100 parts of air-dry fine earth. 
237 
Moisture ... 
3-97 
5-41 
415 
4-71 
2-0 
30 
1-2 
Organic Matter ... 
12-57 
13-92 
18-42 
1216 
9-1 
7-9 
6-3 
Nitrogen ... 
•345 
•358 
•547 
•369 
•19 
•16 
•16 
Insoluble Mineral Matter 
70-50 
67-80 
26-28 
72-00 
23-40 
75-70 
89-50 
Constituents soluble in 
strong acid 
12-96 
12-87 
5115 
1113 
65-50 
1340 
3-00 
Phosphoric Acid, P 2 0^ 
•40 
•29 
•23 
•45 
■36 
•44 
•20 
Sulphuric Acid, S0 3 
•13 
•18 
•27 
•13 
•29 
•32 
•24 
Potash, K 2 0 
•17 
•21 
•13 
•22 
•38 
•17 
•18 
Soda, Na 2 0 
•15 
•18 
•16 
•19 
•12 
•29 
•54 
Magnesia, MgO ... 
*55 
•57 
•58 
•33 
•27 
•41 
•17 
Calcium Carbonate, ) 
CaC0 3 / 
— 
rr 
41-80 
— 
54-00 
•36 
•05 
Lime other than this as 1 
Calcium Oxide, CaO ) 
•70 
•68 
•90 
•31 
5-40 
•70 
•77 
Iron Oxide, Fe 2 0 3 
4-07 
3-91 
2-40 
348 
1-70 
5-43 
•55 
Alumina, A1 2 0 3 
7-27 
734 
4-43 
6-21 
2-89 
5 31 
•31 
Constituents soluble in ^ 
1% Citric Acid. 1 
Phosphoric Acid, P,O s 
•018 
•017 
•007 
•047 
•020 
•015 
— 
Potash, K z O 
■009 
•005 
•023 
009 
•009 
•011 
— 
Reaction ... 
Neutral. 
Neutral. 
Slightly 
Alkaline, 
Neutral. 
Alkaline. 
Neutral. 
Acid. 
Comparison of these figures brings out the following points: 
1. The mechanical composition of the soils A, B, and D is 
very similar to that of a good average fertile loam. The hygroscopic 
water held by all is rather high, especially in the case of B, and 
examination of the soils, in situ, during the progress of the 
work in damp weather showed that A, B and D were retentive of 
water as compared with C, and were rather more sticky in texture. 
The stickiness is possibly due in part to the excess of magnesia 
over the carbonate of lime present as well as to the deficit of lime 
(9). Soil A under Calluna contrasts sharply as regards physical 
character with G—a soil from a Calluna- heath. 
2. In chemical composition A, B, and D are very similar. 
The total amount of soluble mineral matter is high ; the figures for 
phosphoric acid and nitrogen are higher than those in F ; the 
soluble mineral matter is very much higher than that in G which is 
typical of dry sandy heath soils on the Bagshot Beds where Calluna 
is a prominent feature of the vegetation. These facts do not appear 
to agree with the conclusions of Graebner (loc. cit.) and others, as 
to the improbability of Calluna competing successfully with other 
plants on good soils. 
A striking feature is the high proportion of magnesia to calcium 
carbonate in the soils from the mapped area, the latter being 
