266 



ELEMENTS OF AGRICULTURE 



Page. 



Nitrogen in Soils, Importance of 94 



Sources of 04, 98, 106 



Forms of 08 



Necessity of 106 



Loss of 106, 108 



Nitrogenous Matter. See Proteim 



Non-Nitrogenous Matter, In Plants 48 



In animals 184 



Estimation of 201 



Nutrients .'. 202 



Nutritive ratio 209 



Oats, As a crop 157, 158 



Roots of 41 



Organic matter of plants 46 



Of soils. 70, 78, 79, 86, 94, 95, 98, 106, 107 



Organs of plants , 38 



Owls. See Birds of Prey. 



Oxidation 25 



Oxygen in air 24, 25 



Properties of .......;... 25 



In soils .* 61, 124 



Pastures, Classes of 168 



Permanent 168, 169 



Temporary 169, 170 



Peaty soils 74 



Perennials 33 



Phosphates, In plants .50, 58 



In soils 83, 110-113 



In fertilizers 133, 138-143 



Phosphate Rock, Where found 138 



Appearance of 139 



Composition of 139 



Phosphoric acid 51 



Phosphorus, Properties of 50 



In soils 83, 110 



In fertilizers 133 



In phosphate rock 139 



Plants, Classes of 33 



Seed of 33, 34, 35 



Parts of 38-43 



Composition of 45-53 



Food of 55-62 



Growth of 63-66 



Plant food 58 



Plowing 122, 125 



