18 BULLETIN 784, U. S. DEPARTMENT OF AGRICULTURE. 
comparisons made between the yield with treated seed and with 
nontreated seed, both as to quality and quantity. 
Correlations. — Problems in arithmetic growing out of comparisons 
between yields of treated and nontreated seed, together with cost 
of production in either case, including cost of treating compared with 
increase in yield, will be found valuable. 
Written reports on treating seed potatoes and of the planting pro- 
cesses will afford language material. 
LESSON X. 
Subject. — Cultivation — first. Later. 
Problem. — To study the correct methods of potato crop cultivation 
in order that the maximum yield may be secured. 
Sources of information. — Farmers' Bulletin 365 (5 cents), 386 (5 
cents), 407, and bulletins from State agricultural college. 
Illustrative material. — Clip from farm papers pictures showing 
cultivation of potatoes; pictures of various kinds of cultivators and 
tools for tillage. If possible, have some of these cultivators brought 
to school where they may be examined. Visit a farm and see these 
tools in actual operation. 
Class exercise. — The following principles in potato cultivation are 
noted and should be discussed as a basis for the practice work in 
growing potatoes: 
Early cultivation: 
1. Is it safe to assert that the major part of the cultivation of the 
potato crop should be done before planting. 
2. Poor cultivation often the cause of poor yields. 
3. Before potatoes are up, the field should be blind cultivated with 
a spike-toothed harrow or weeder. 
4. Weeds should be destroyed and ground mulched. 
5. After potatoes are up, deeper cultivation should be practiced, 
depth up to 8 to 10 inches, depending upon soil and locality. 
6. Usually level cultivation brings better results than hilling. 
(Under what circumstances is ridging the better practice?) 
7. The frequency of early cultivation depends largely upon the 
character of the season. 
8. The things to be accomplished: Keeping down the weeds and 
conserving moisture. 
Later cultivation: 
1. Depth, shallow; form, level; ridge slightly after tubers are 
formed to prevent sunburn. 
2. How long kept up should be determined largely by the season 
and condition of crop. As long as plants are green they are pro- 
ducing tubers. 
