The Water Requirement of Plants (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1913 Excerpt: ...the difference in the amount of soil evaporation from the series, factors which obviously have no dependence one upon the other; and, second, that if the soil evaporation from the two series was made equal, the water requirement of the two series would have to be equal, irrespective of the method of treatment It is evident from this analysis that the method of reduction employed by Pfeiffer, Blanck, and Fliigel is not sound, and that consequently no weight can be attached to the data as given. The data without the correction for evaporation are, unfortunately, not given in the original paper. Table XIII.--Effect of different soil-moisture contents on the water requirement oj oats,1 according to Pfeiffer. Blanck. and Fliigel (1912, p. 230). 1 Twenty-tour plants of Ligowo oats were grown in each pot. The pots contained 18 kilograms of sand of low moisture-holding capacity. There were four pots for each determination. The dry matter pro dueed is not given. 9 Applied as ammonium nitrate. 1 Pfeiffer, Blanck, and Fliigel omitted four pots in calculating this mean because the plants were not artificially shaded. These pots apparently formed the series whose mean is 383 4. CONCLUSIONS. In general, the results of the experiments herein recorded show an increase in the water requirement when the water content of the soil approaches either extreme. Many of the experiments were conducted in open pots and the evaporation estimated by means of check pots, which is an uncertain procedure. Extreme moisture conditions might, however, affect the water requirement indirectly. With a high water content, the aeration would be reduced and the soil solution would be diluted. In the case of soils kept at a low water content, the small amount of water required from time to ti...