Received for publication June 11, 1973. Paper No. 4076 of the Journal Series of the North Carolina State Uniyersity Agricultural Experiment Station, Raleigh.
Associate Professor, Dept. of Horticultural Science, and Extension Assistant Professor, Dept. of Biological & Agricultural Engineering, respectively.
The authors wish to express their appreciation to Everett and Jake Lutz, grower-cooperators, for their interest and assistance which made this research possible, and to Duke Power Co. for their assistance.