ol 
Hollrung ' is of the opinion that the alkalinity of calcareous soils 
is one of the principal causes of the chlorosis of grapevines, as they 
seem to prow best on slightly acid soils. Molz? is of the opinion that 
the chlorosis of grapes is largely caused bythe physical condition of 
the soil. 
From the previous work on chlorosis it is then apparent that certain 
plants growing on calcareous soils become chlorotic, and that treat- 
ment with certain iron salts is more or less effective in ameliorating 
the chlorotic condition. As to just how the carbonate of lime acts in 
causing the chlorosis there is some difference of opinion. 
To ascertain if possible how the lime disturbs the physiology of 
pineapples and induces the chlorosis the following investigations 
were made. 
EFFECT OF SOIL ALKALINITY AND ASSIMILABLE LIME IN 
CAUSING CHLOROSIS. 
Chemically calcareous soils differ chiefly from ordinary soils in 
having an alkaline reaction and in containing a large amount of easily 
assimilable lime. If the mere alkalinity of the calcareous soils were 
the causative feature it would be expected that soils rendered alkaline 
with sodium carbonate would also produce chlorotic plants. If the 
large amount of assimilable lime causes the chlorosis it would be 
expected that soils treated with calcium sulphate would produce 
chlorotic plants. To determine whether the chlorosis is caused 
either by the alkalinity or the large amount of assimilable lime, pot 
experiments were carried out. 
The experiments were carried out after the manner described on 
page 21 except that the pots receiving sodium carbonate were kept 
in the glass house to prevent loss of the alkali by leaching. 
In the experiment with sodium carbonate the soil used was No. 
213. Five check pots received nothing, five received sufficient 
anhydrous sodium carbonate to give the soil a content of 0.01 per cent, 
five received sodium carbonate to 0.05 per cent, and five sodium 
carbonate to 0.10 per cent of the weight of soil. The condition of the 
plants at the end of 10 months is given in the following table: 
Results of experiment in which sodium carbonate was added to sandy soil. 




Average 
Content of font of 5 
‘ontent o weight o 
NagCO; in soil. Appearance of plants. plants at 
end of 10 
months. 
. Grams 
Check.....:....}| Allplants dark green and vigorous throughout the experiment...........-..- 
0.01 per cent. ..|} All plants dark green but stunted throughout the experiment.............- 294 
0.05 percent... -|.....do.....4-.-+.. Per atic et ee | eee | Pee aeeeecer reer sere s | 264 
0.10 per cent.. | All slips remained green with practically no growth...........-.--.++------ 185 

1M. Hollrung. Landw. Jahrb., 37 (1908), pp. 497-616. 
2E.Molz. Centbl. Bakt. [etc.], 2. Abt., 19 (1907), Nos. 13-15, p. 461; 16-18, p. 563; 21-23, p. 715; 24-25, 
Pp. 788; 20 (1907), Nos. 1-3, p. 71; 4-5, p. 126. 
(Bull. 11] 
