Illustrations have been moved to paragraph breaks near where they are mentioned.

Punctuation has been made consistent.

Variations in spelling and hyphenation were retained as they appear in the original publication, except that obvious typographical errors have been corrected.

p. 26: The description of the test plots is missing a description for No. 1, and the description given for No. 1 is actually for No. 3.

The following change was made:

p. 30: delvered changed to delved (the deep-delved cellars)