|
|
Hygroscopic power of soils
|
75
|
|
|
Capacity of soils for absorbing and retaining heat
|
76
|
|
|
Explanation of dew
|
77
|
|
|
Heat of soils
|
78
|
|
|
Heat in rotting farmyard manure
|
78
|
|
|
Causes of heat of fermentation
|
79
|
|
|
Influence of colour on heat-retaining power
|
80
|
|
|
Power of soils for absorbing gases
|
81
|
|
|
Gases found in soils
|
81
|
|
|
Variation in gas-absorbing power of soils
|
82
|
|
|
Absorption of nitrogen by soils
|
82
|
|
|
Requirements of plant-roots in a soil
|
83
|
|
|
Influence of tillage on number of plants in a certain area
|
86
|
|
|
Comparison of English and American farming
|
86
|
|
II.
|
Chemical composition of a soil
|
87
|
|
|
Fertilising ingredients of a soil
|
87
|
|
|
Importance of nitrogen, phosphoric acid, and potash in a soil
|
88
|
|
|
Chemical condition of fertilising ingredients in soils
|
89
|
|
|
Amount of soluble fertilising ingredients in soils
|
90
|
|
|
Value of chemical analysis of soils
|
90
|
|
III.
|
Biological properties of a soil
|
92
|
|
|
Bacteria of the soil
|
92
|
|
Recapitulation of Chapter I
|
96
|
|
|
|
APPENDIX TO CHAPTER I.
|
|
NOTE
|
|
|
I.
|
Table of absorptive power of soil substances by Schübler
|
98
|
|
II.
|
Table of rate of evaporation of water in different soils by Schübler
|
99
|
|
III.
|
Table of hygroscopic power of soils dried at 212° F. (Davy)
|
99
|
|
IV.
|
Gases persent in soil
|
100
|
|
V.
|
Amount of plant-food in soils
|
100
|
|
VI.
|
Chemical composition of the soil
|
101
|
|
VII.
|
Forms in which plant-foods are present in the soil
|
107
|
|
|
|
CHAPTER II.—FUNCTIONS PERFORMED BY MANURES.
|
|
Etymological meaning of word manure
|
109
|
|
Definition of manures
|
110
|
|
Different classes of manures
|
111
|
|
Action of different classes of manures
|
113
|
|
|
|
CHAPTER III.—POSITION OF NITROGEN IN AGRICULTURE.
|
|
The Rothamsted experiments and the nitrogen question
|
115
|
|
Different forms in which nitrogen exists in nature
|
116
|
|
|
Relation of "free" nitrogen to the plant
|
117
|
|
|
Combined nitrogen in the air
|
118
|
|
|
Amount of combined nitrogen falling in the rain
|
119
|
|
|
Nitrogen in the soil
|
120
|
|
|
Nitrogen in the subsoil
|
121
|
|
|
Nitrogen of surface-soil
|
121
|
|
|
Amount of nitrogen in the soil
|
123
|
|
|
Soils richest in nitrogen
|
123
|
