404 BOTANICAL GAZETTE [MAY 
that even at the latter moisture content notable nitrogen fixation 
occurs in what is virtually a saturated soil. 
TABLE I 
INFLUENCE OF MOISTURE CONTENT ON NITROGEN FIXING POWER OF SANDY SOIL 
Per gon — ir tend lAv. N fixed 
* rgtam 
Culture no. (ive. Be isn N found mgs. of peo 98 ar of maine Wake 
2.5 per cent) 
Tic eesew eae ° 31.15 ° ° 
Bees owes es fe) 3h. 15 ° ° 
ary aren Dae 4 Sr. 35 7° 
88 
y eco ean Boe 4 32.20 1.05 
Gee Cases 8 34.65 4.50 
3.68 
sale Aiton ene 8 36,00 3.85 
fae at ree agra 12 37.30 5-95 
5-95 
ae Rae ae 12 37.10 5.95 
2 pene apie ue saee 16 26°95 5.60 
5-95 
1 eS Ae ge 16 37.45 6.30 
Plies oe. ies 20 39.20 8.05 
8.05 
BAe ede a ess 20 39.20 8.05 
4 i RE ee 24 30.55 8.40 
8.05 
cf See bg eae ah 24 38.85 7.70 
ot wae eee 28 38.15 7.00 
7.18 
W608) (ci, 28 38.50 7.35 
2 YAO eo SBE 32 36.40 5.25 
4.55 
Tol Geo. ee 32 35.00 3.85 
LU erate ne asia 36 33-95 2.80 
2.98 
PO lye es 36 34.30 3:35 
With small amounts of moisture in the soil some interesting 
results are obtained, also, as indicated in the table. Virtually no 
nitrogen fixation or very little takes place with a moisture content 
of 4 per cent (air dry basis), but a very marked increase occurs when 
