18 WATER REQUIREMENT OF PLANTS. 
Table VII. — Effect of different soil-moisture contents on the water requirement of carrots 
and ray-grass, according to Wimmer — Continued. 
RAY-GRASS— Continued. 
Year, period, and plat. 
Previous fertilizer. 
Soil 
per 
pot. 
Fertilizer 
per pot. 
Soil 
Mean 
mois- 
dry 
ture. 
matter. 
Per ct. 
Grams. 
15 
92.4 
18 
95.6 
15 
93. 8 
18 
98.7 
15 
92.5 
18 
100.4 
15 
90.0 
18 
113.4 
15 
88.4 
18 
104.3 
15 
90.0 
18 
102.1 
15 
80.2 
18 
90.6 
15 
84.7 
18 
93.5 
15 
96.2 
18 
95.9 
12 
41.5 
15 
46.2 
18 
50.9 
12 
39.9 
15 
48.6 
18 
46.9 
12 
43.0 
15 
46.0 
18 
46.3 
9 
41.5 
11.5 
44.0 
14 
46.4 
7 
26.0 
9 
36.0 
11 
33.8 
Water 
require- 
Apr. 17 to Sept. 26, 1905: 
B 3 i ' None, 1901 to 1905. 
H3i. 
.do. 
No potash, 1902 to 1905. 
F 3 i No potash since 1901 . 
Waldau > 87, 88, 89 No potash since 1903 . 
F 6 i Kainit since 1902. . . . 
Juetrichau sand ' 
Buhlendorf sand ' 
Grams. 
7,919 
Grams. 
7HS 
0.155 
.155 
.776 
.776 
.155 
.155 
.776 
.776 
7,768 
8,042 
7, SOS 
8,000 
8,000 
155 
155 
776 
776 
280N 
280 
280 
280 
280 
280 
313 ±4 
333±17 
306 ±21 
336±1 
310±7 
350±16 
305 ±13 
290±4 
319±32 
303 ±7 
312±17 
311±7 
341±32 
345±12 
311±11 
369 ±7 
262 ±9 
331 ±3 
406 ±5 
440±4 
439 ±27 
352±19 
397±18 
458±11 
373±35 
454±19 
523±6 
423±6 
441 ±5 
461 ±4 
521 ±14 
422±23 
490±27 
1 The mean of two determinations. 
PREUL S EXPERIMENTS. 
Preul (1908) investigated the effect of different soil-moisture con- 
tents for varying periods upon the water requirement of wheat. 
The experiments were conducted with two different soils and the 
soil moisture was maintained at 45 and at 80 per cent of the mois- 
ture-holding capacity. Open pots were used in these experiments. 
A correction based upon the evaporation from check pots was made 
for evaporation, although it was not clear that a check w r as provided 
for each series of observations. The results (Table VIII) show a 
gradual decrease in the water requirement with the increase of the 
period during which the low T er soil-moisture content was maintained. 
The lowest water requirement was obtained in the soil kept continu- 
ously at the low r er water content. 
285 
