87

XI.--SPADING AND PLOWING 90
Spading the soil 90
Plowing 91
Why we spade and plow 91
Parts of a plow 92
Characteristics of a good plow 95
The furrow slice 96
How deep to plow 96
"Breaking out the middles" 97
Ridging the land 98
Time to plow 98
Bare fallow 100

XII.--HARROWING AND ROLLING 101
Harrowing:
Why we harrow
Time to harrow 101
Types of harrows 102
Rolling 106

XIII.--LEAVES 108
Facts about leaves 108
The uses of leaves to plants:
Transpiration
Starch making
Digestion of food
Conditions necessary for leaf work 109
How the work of leaves is interfered with 115

XIV.--STEMS 120
What are stems for? 120
How the work of the stem may be interfered with 126

XV.--FLOWERS 128
Function of flowers 128
Parts of flowers 129
Functions of the parts:
Cross pollination 130
Value of a knowledge of the flowers 134
Fruit 136

PART II

SOIL FERTILITY AS AFFECTED BY FARM OPERATIONS AND
FARM PRACTICES

Chapter Page

XVI.--A FERTILE SOIL 141
Physical properties:
Power to absorb and hold water
Power