. Proceedings of the American Society of Agronomy . Fig. 38.—Illustration of methods of determining water loss from cuttings. 264 PROCEEDINGS OF THE AMERICAN SOCIETY OF AGRONOMY. It is necessary that the branch or leaf to be tested be so inserted thatit is airtight. The small tube is scaled so that the amount of waterrequired by the leaf or branch can be determined from time to figures a very simple apparatus for determining water loss. Wide-mouthed bottles with ordinary corks can be utilized. A battery ofthis kind of evaporimeter can be quickly set up, and is convenientfor comparing th
. Proceedings of the American Society of Agronomy . Fig. 38.—Illustration of methods of determining water loss from cuttings. 264 PROCEEDINGS OF THE AMERICAN SOCIETY OF AGRONOMY. It is necessary that the branch or leaf to be tested be so inserted thatit is airtight. The small tube is scaled so that the amount of waterrequired by the leaf or branch can be determined from time to figures a very simple apparatus for determining water loss. Wide-mouthed bottles with ordinary corks can be utilized. A battery ofthis kind of evaporimeter can be quickly set up, and is convenientfor comparing the relative loss between different varieties of plantsunder varying conditions, such as shade and sunshine. Of coursethe records can only be taken for one or two days before the cuttingwilts, but the method is often very useful. Methods of Detennining Water Loss Where Grozmng Plants are Used. Fig. 39 illustrates three methods which have been utilized for thispurpose, a is a small flowerpot with a growing plant. After the. Fig. 39.—Illustration of methods of determining water loss from growing plants. plant has been well watered, the top of the pot is covered with arubber cloth to prevent evaporation. Hourly or daily water loss canbe determined by weighing, until the plant has used all the availablewater in the pot. The experiment may be continued by renewing thewater supply, b shows the wire basket method of growing seedlings,the wire basket and surface being covered with paraffin to prevent MONTGOMERY: WATER REQUIREMENTS OF CROPS. 265 evaporation from the soil, and water is added as needed, through theopening where the plants are growing, c illustrates a method of grow-ing the plant in a culture solution and determining the water loss bymeasuring the change in level on the graduated siphon. By renew-ing the culture solution from time to time, a very normal plant can begrown in this way for several days or even weeks. Automatic Methods of Securing a Record of the Water Loss.
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