38 
WATER REQUIREMENT OF PLANTS. 
Table XXVIII. — Effect of different fertilizers and crop sequence on the water requirement 
of oats, according to Von Seelhorst (1899, pp. 372, 376-377). 
Water content, in terms of moisture-holding 
capacity. 2 
Crop-sequence experiment. 3 
Fertilizer. 1 
49 to 54 per 
cent. 
59 to 64 per 
cent. 
64 to 74 per 
cent. 
Mean 
water 
re- 
quire- 
ment. 
Oats. 
Oats follow- 
ing mustard. 
Dry 
mat- 
ter. 
Water 
re- 
quire- 
ment. 
Dry 
mat- 
ter. 
Water 
re- 
quire- 
ment. 
Dry 
mat- 
ter. 
Water 
re- 
quire- 
ment. 
Dry 
mat- 
ter. 
Water 
re- 
quire- 
ment. 
Dry 
mat- 
ter. 
Water 
re- 
quire- 
ment. 
K 
Grams. 
40.2 
55.2 
38.5 
49.9 
39.6 
41.3 
41.3 
46.8 
290 
230 
268 
225 
260 
227 
247 
236 
Grams. 
51.2 
67.5 
49.9 
86.7 
48.8 
65.9 
52.9 
84.0 
291 
243 
290 
237 
313 
225 
291 
220 
Grams. 
47.9 
75.5 
54.4 
95.1 
52.6 
92.9 
51.5 
108.3 
302 
231 
283 
232 
307 
222 
306 
216 
294 
235 
280 
231 
293 
225 
281 
224 
Grams. 
62.5 
62.4 
72.6 
90.3 
67.4 
79.3 
76.0 
91.5 
291 
363 
255 
258 
280 
277 
249 
254 
Grams. 
17.5 
36.4 
15.3 
21.2 
18.1 
31.3 
16.8 
23.3 
542 
N 
343 
P 
584 
KNP 
403 
Check 
506 
KN 
350 
KP 
535 
PN.... 
457 
235 
264 
262 
278 
465 
1 P represents 1 gram of phosphoric acid; K, 1 gram of potash; N, 1 gram of nitrogen. 
2 Harvested just before the milk stage; 20 kilograms per pot. Two pots were used in each treatment, 
but the data for the individual pots are not given. 
3 Eleven kilograms of earth per pot. 
WILMS'S EXPERIMENTS. 
Wilms (1899) conducted a somewhat more elaborate experiment 
with early potatoes. The results of this experiment are given in 
Table XXIX, the water requirement being expressed in terms of 
the green weight. The zinc pots in which the experiments were 
conducted held about 15 kilograms of soil. The surface soil was left 
dry throughout the experiment, water being added below the surface 
through Liebscher's aerating device. All tubers under 5 grams in 
weight were discarded and the ratio is expressed in the green weight 
of the remaining tubers. An analysis of the soil preparatory to 
the experiment showed it to be rather poor in phosphoric acid, 
and 1 gram of phosphoric acid (P 2 5 ) was therefore added in 
the form of ammonium calcium phosphate to each pot. The mean 
water requirement for each treatment shows that the various salts 
reduced the water requirement very slightly. The low yield and 
high water requirement when potassium chlorid was used is attrib- 
uted to the fact that this salt was impure, containing about 4 per 
cent of potassium chlorate. 
285 
