60 
Indian Forest Records, 
[Vol. VIII 
aerated sand, seedlings soon become unhealthy in loam 
and leaf-mould if kept constantly moist whether by watering 
or by decreasing evaporation, see l.c. part I, 1914, paras. 
12 (3), 18, 19. 
(16) In the ordinary loam characteristic of the local sal forests, 
sal seedlings soon become unhealthy if the soil is kept con- 
tantly moist. In ten days the less vigorous seedlings are 
killed and after 6 weeks 100 per cent, of the seedlings show 
more or less extensive death and decay of the root. Consider¬ 
able root damage of this kind may occur in plants which 
still retain their green leaves and appear healthy above 
ground, see l.c. part I, 1914, para. 26,30 (4) (5) and Appendix 
II, also l.c. part III, 1916, paras. 5, 6. 
(17) In loam taken from a local sal forest and which had been 
consolidated by pressure, 25 per cent, more sal seedlings 
were found to die during the rains than in a non-consolidated 
sample of the same soil and those plants which survived 
were found to have an abnormal root system confined to 
the superficial better aerated layers of soil, see l.c. part I, 
1914, para. 22 (2) (3) and Plate II. 
(18) When water is held in contact with the ordinary sal forest 
loam mentioned in (16) above, it becomes heavily charged 
with CO 2 and impoverished as regards its oxygen supply. 
The bad growth noted in (15) and (16) above is at present 
believed to be due chiefly to a deficiency of oxygen and a 
poisonous accumulation of C0 2 in the soil and, throughout 
the present work, this has been provisionally termed “ bad 
soil-aeration.”* This appears to be another limiting factor of 
great importance for the development of sal seedlings, see 
l.c. part III, 1916, para. 8. 
That the limiting factor in this case is not water per se is shown 
by the fact that sal seedlings can be successfully grown 
in water cultures, see l.c. part III, 1916, para. 14. 
(19) Sowings in the local sal forests in 1912, 1913, 1915, 1916, 
1917 and 1918 have shown that seedling development is 
invariably better, both in favourable and unfavourable 
seasons, in cleared patches and narrow strips with full over¬ 
head light and side-shade than in the shade plots where 
the overhead cover was not removed. In the shade plots, 
* Results of further work dealing with the influence of CO 2 and oxygen on the root 
growth of seedlings in water cultures will shortly be published in another paper, see als 9 
Agricultural Journal of India , Vol. XIII, Part III, pp. 433-436, July 1918. 
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