96 PLANT GROWTH 



a poor root system which would be detrimental to a lawn and 

 most other perennial plants (Plate XIII). A moderate in- 

 crease in the soil moisture is necessary for excessive vegeta- 

 tive growth. 



Most plants may be given a quicker start in the spring 

 by applying nitrogen to get a number three balance. The 

 larger plant produced in this way results in more photo- 

 synthesis which tends to increase the carbon to nitrogen ratio 

 in mid-summer and fall and to develop a well-hardened plant 

 with a food reserve. This is the best kind of balance for 

 most plants. 



When sun-loving plants are planted in the shade photo- 

 synthesis will be retarded and they will tend to have high 

 nitrogen and, depending on the density of the shade, will 

 respond as in number three, or number four if in dense shade. 



REFERENCE 



Kraus, E. J., Sources and Cycles of Nutrient Elements, Yearbook of Agriculture, U. S. 

 Department of Agriculture, pp. 405-417, 1939. 



