292 NATURE STUDY AND AGRICULTURE 



Does under drainage tend to make a long or short root 

 system? Which plants will fare better during the dry 

 season, those whose roots have grown to a good depth or 

 those whose roots are near the surface ? 



To prove how dependent plants are upon water, try the 

 following experiment. Have growing side by side in pots 

 or cans plants of the same kind : sunflowers, beans, or any 

 house plant. Give to one all the water needed. From 

 the other withhold water entirely for a number of days. 

 What is the result ? Now begin to water the wilting plant 

 and note effects. What is it that helps to hold an herba- 

 ceous plant rigid and upright ? Is this an important use 

 of water in plants ? 



It is possible to determine with some accuracy how 

 much water plants contain. Pull up two or three plants. 

 Weeds will serve the purpose well. Wash the soil off the 

 roots and weigh the plants. Spread them out on a sheet of 

 paper in the room and weigh at intervals of three or four 

 days. Do they continue to lose water for any length of 

 time ? By what physical process are they losing the water ? 



Can you think of any way that we may prove whether 

 or not it is the water alone that supplies the needs of the 

 plants ? Has rain water any of the chemical compounds 

 in it that soil water contains? 



Experiment. Fill two pots or cans with clean sand, 

 fine gravel, or sawdust. Plant in each three or four beans, 

 peas, or sunflowers. Water one with rain water, the other 

 with well water. If you wish to be certain that the water 

 contains plant food, stir a quantity of rich soil having plenty 

 of humus into some rain water, let it stand several days, 

 then drain off the water and use this instead of well water 



