86 Gardening 



Effects of the gardener's work on the supply of soil 

 water. From what we have now learned, it will be under- 

 stood that garden plants can use only the capillary water 

 of the soil ; that free water about roots is harmful to them ; 

 and that to fit a soil for garden purposes, the free water 

 must be drained off and the soil made to hold as much 

 capillary water as possible. 



Nearly everything the gardener does to the soil affects 

 the water supply in it. Drainage has for its direct aim 

 the removal of free water, which makes it possible for the 

 roots of crops to penetrate deeply. The addition of 

 lime, manure, and compost causes the free water to drain 

 off more quickly and increases the amount of capillary 

 water held in the soil. Plowing and spading also increase 

 the power of the soil to hold capillary water, and one of 

 the reasons for the cultivation of growing crops is to 

 retain the water in the soil for the use of the plants. 



The gardener, therefore, in large measure controls the 

 supply of water in the soil. He removes the excess that 

 is harmful ; he increases the power of the soil to hold 

 water in suitable form for his plants ; he saves or con- 

 serves the water present in the soil ; and he supplies 

 water when it is needed. By a study of the soil and of 

 the water in it, he can do the things that regulate the 

 water supply to the needs of his crops. 



Questions 



About what proportion of the entire living plant is composed 

 of water ? What are some of the uses of water to a green plant ? 

 Give some facts that explain why plants need an abundant and 

 a continuous supply of water. 



