16 BULLETIN 784, U. S. DEPAKTMENT OF AGKICULTURE. 
do the yields on the various types compare ? Compare the quality of 
the potato crop raised on the different soils. How deep do the farm- 
ers of the district plow their potato soil? What is the common 
practice as to the time for plowing, fall or spring? What advan- 
tages can be found in either time of plowing? If the potato crop is 
one in a rotation, what is the usual practice in the district .regarding 
fertilizers? If without a rotation, what is the practice? Xote the 
farms that use green manure, that use stable manure, those that use 
commercial fertilizers, or a combination of fertilizers; and compare 
yields, both as to amount and to quality. Study the methods used 
by a successful potato grower of the district. 
Correlations. — Correlations in language will be suggested by the 
various reports in practical exercises. Fertilizer costs, cost of plow- 
ing and otherwise preparing the land, will provide suitable correla- 
tions in arithmetic. In geography, a study of the commercial fer- 
tilizer as to source, manufacture, and shipping routes, will prove 
interesting and instructive. 
LESSON IX. 
Subject, — Planting potatoes including the treatment of seed. 
Problem. — How should potatoes be prepared for planting, treated 
for disease, and when is the best time for planting? 
Sources of information. — Farmers' Bulletins 386, 407, and 544; 
bulletins from State college of agriculture ; textbooks in agriculture. 
Illustrative material. — Specimens of diseased potatoes should be 
brought to the school and a comparison made between them and po- 
tatoes free from disease. Potatoes properly cut should also form a 
part of the illustrative material. The formula for treating potatoes 
should be placed on a chart in the room. Secure a small amount of 
formalin, and with the assistance of the class prepare some of the 
solution of the right strength for treating potatoes. 
Class exercise. — Discuss the following topics: 
1. Preparation for planting. — Treating the seed, purpose, diseases 
that may be treated, solutions used, method, results, cutting the seed, 
and principles involved which follow: 
(a) Seed pieces should be blocky in shape to make surfaces as small as pos- 
sible. 
(o) The probability in most cases that the seed and eyes are more vigorous 
makes it better to cut each tuber in such shaped pieces that it will give the 
largest number having eyes from the seed end. 
(c) To make sure of one good eye on every seed piece, it is well to have two 
wherever possible. 
(d) The average weight of the) seed must be adjusted to the needs of the 
crop for the soil planted — method of cutting, cutting racks, value of whole seed 
compared with cut seed. 
