Fertilizing and Watering Trees 



4. What is the structurt' oj the soil? Soil structure reflects 

 organic matter content and results ironi the aggregation of 

 the various soil particles. Soil that remains in clusters or is 

 crumbly when sifted through the fingers even when moist 

 is most desirable. 



5 . /,s the subsoil compacted, a tight clay, or does water move into it 

 readily? When water remains in a soil hole for 24 hours 

 following a rain, the soil is poorly drained. Much of the pore 

 space in such a soil is saturated with water for extended 

 periods during the growing season; in effect, that saturation 

 reduces the depth of topsoil suitable for tree growth. 



6. Has the soil been disturbed? Soil compaction, a change in 

 drainage, the removal of a layer of topsoil, or a fill of clay 

 above the original topsoil often reduces plant vigor and 

 growth. 



Soil with deep topsoil, silty loam texture, aggregate structure, 

 high organic matter content, good aeration, moderately high 

 water-holding capacity, and a subsoil that allows internal 

 draining is ideal for growing trees and seldom, if ever, will 

 fertilization of trees be required. Soil with a clay subsoil and 

 less than 8 inches of topsoil that is light brown or gray in 

 color, sandy in texture, and sticky when wet, is much less 

 satisfactory for optimum tree growth. Under these soil 



Figure 3. The soil-profile tube is a handy tool for removing cores from the 

 upper 10-14 inches of soil. Many properties of the soil can be observed by 

 examining such cores. 



