36 
WATER REQUIREMENT OF PLANTS. 
singly. In the clay soil phosphorus and nitrogen combined gave a 
water requirement lower than either phosphorus and potassium or 
potassium and nitrogen. In the sand phosphorus and nitrogen gave 
the same result as potassium and nitrogen, while potassium and 
phosphorus gave a somewhat higher water requirement. 
Table XXVI. — Effect of different fertilizers on the water requirement 1 of oats 
at Gottingen, according to Liebscher (1895, p. 211). 
Clay, 9,160 grams; 
water, 2,210 grams. 
Sand, 11,700 grams; 
water, 1,740 grams. 
Dry matter, 
grams. 
Water require- 
ment. 
Dry matter, 
grams. 
Water require- 
ment. 
Water requirement, using- 
32.1 
344±9 
35.2 
313±8 
45.6 
311±1 
129.7 
194±2 
43.2 
270±7 
35.7 
307 ±5 
KNP Check. KN KP PN Mean. 
123.2 
173±3 
149.3 
178±1 
2 32.1 
349±9 
34.0 
332±7 
42.2 
319±7 
133.3 
192±2 
42.6 
264±2 
36.0 
299±6 
122 
177±2 
139.7 
192±1 
278 
251 
1 Probable errors are computed by the writers from Liebscher's data; three pots were used in each deter- 
mination. Three applications of fertilizer were made during the season, the amounts applied- per pot 
each time being as follows: 0.475 grams of N; 0.482 grams of P 2 5 ; and 0.906 grams of K 2 0. 
2 Liebscher gives 32.7, which is evidently an error. 
MAERCKER S EXPERIMENTS. 
Maercker (1896) investigated the effect of various potassium fer- 
tilizers and of sodium chlorid on the water requirement of white 
mustard. As a source of potassium he used kainit (a hydrous magne- 
sium sulphate containing potassium chlorid) and carnaUit (a hydrous 
chlorid of magnesium and potassium). The soil used was sand 
with an admixture of 2.5 per cent of peat. The capacity of the pots 
is not stated, but was probably small, 6 kilograms of soil being used 
in other fertilizer experiments with mustard. The pots were not 
covered, and check pots without plants were not used. The sum- 
mary of results (Table XXVII) shows that all the fertilizers used, 
including sodium chlorid, reduced the water requirement. 
Table XXVII. — Effect of potassium and sodium salts on the water requirement of white 
mustard, 1 according to Maercker (1896, p. 21). 
Fertilizer per hectare. 
Without potash 
1,000 kilograms kainit. . . 
2,000 kilograms kainit . . . 
2,000 kilograms carnallit . 
2,000 kilograms NaCl. . . . 
Mean. 
per cent of mois- 
ture-holding ca- 
pacity (18 per 
cent water). 
Dry 
matter. 
24.4 
25.5 
25.3 
24.0 
16.6 
Water 
require- 
357 
309 
305 
333 
321 
20 per cent of mois- 
ture-holding ca- 
pacity (8 per 
cent water). 
Dry 
matter. 
Grams. 
12.6 
12.1 
Water 
require- 
2S2 
226 
143 
200 
197 
210 
water 
require- 
320 
268 
224 
267 
259 
One pot only was used for each treatment. These data are also found in Maercker, 1896a (p. 15). 
285 
