1913] LIPMAN & WILSON—TOXIC SALTS AND ACIDS 419 
acid treatment of soil may prove a valuable practice. The follow- 
ing experiment was considered, therefore, of very great interest 
as a preliminary test of the physiological effect of H.SO, on plants, 
and its arrangement and results are set forth in table IV. 
TABLE IV 
Errects oF H,SO, ON PLANTS 
DRY WEIGHT OF VETCH Dry WEIGHT OF 
WHEAT 
H.SO, ppm. 
Roots gm. Tops gm. Tops gm. 
OSs es ee ee 4:5 17:6 18.50 
SOu. ce ee ee Sis 15.0 12.20 
BOO os ek en ce ee ee 6.0 1g-5 16.65 
200 Oo es Pen ea 2.5 8.0 18.50 
BOO oo teers ee Oe eee 4.0 19.5 20.50 
BOO So So als Sere en 4.0 17.0 T0.50 
O00 ideo ee) oman eee ee 5.0 15.5 26.20 
The foregoing data would seem to indicate that considerable 
amounts of H,SO, may be added to soils without injury to plants. 
The objection, of course, to which such additions of acid would 
be open to in practice, is that when the lime and other bases have 
been neutralized in the soil by the acid, any further additions 
to the latter would tend to make an acid soil which is unfavorable 
for plant growth, but it is at any rate safe to assume that on strongly 
alkaline soils, where that condition is the interfering fact with plant 
growth, the acid treatment of soil should ameliorate its unfavor- 
able condition to a marked degree. Moreover, we are not without 
a basis in fact for our assumption. SymMMonpDs™ has shown that 
when nitric acid to the extent of 600 pounds per acre was mix 
with artesian water and applied to soils containing alkali, the yields 
of crops were greatly increased. It may be argued, of course, that 
this case is not an analogous one, since the nitric acid combines 
with bases in the soil to form nitrates which are an important food 
and even stimulant to plant growth, but it should also be remem- 
bered that, as one of us has already pointed out elsewhere, in a publi- 
cation above cited, on the basis of direct investigations, that Na,SO,, 
produced through the action of H,SO, on Na,CO, (black alkali), 
is a stimulant to nitrification, and that thus an application of 
1 Agric. Gaz. N.S. Wales 21:257~266. 
