ABSTRACT
This manual was written with the recognition that it might be used in any of these situations. The investi gations include many that need no specialized equipment or facilities and some that can be carried out when the weather outside is not conducive to plant growth. Many of the investigations can be carried out in a variety of climates; some can be abbreviated if time is short; some can be simplified or done at a smaller scale if the suggested facilities or equipment are not available.
