

CONTENTS 



Bulletin No. 173. — Seasonal Nitrification as Influenced by Crops 



and Tillage. Page 



Introduction "i 



Description of the soil in which the experiments were conducted S 



Field history of the plats 9 



Methods of making determinations 9 



Discussion of results of determinations 12 



Nitrates in the fallow plat 12 



Nitrates in the spring-wheat plat 14 



Comparison of nitrates in fallow, spring-wheat, and corn plats__ 16 



Withdrawal of nitrates by corn roots 17 



Relation of nitrification to field factors 18 



The disappearance of nitrates 21 



Denitrification 22 



Seasonal variations in nitrification 23 



Change of water-soluble nitrates to albuminoid nitrogen 25 



Relation of nitrification to summer fallow 26 



Summary 27 



Index 29 



Bulletin No. 174. — The Control of Peach Brown-Rot and Scab. 



Introduction 7 



Teach brown-rot S 



History of the disease S 



Economic importance of the disease 9 



Nature of the disease and the fungus causing it 11 



Influence of the weather 12 



Influence of insects 13 



Peach scab ' 13 



Character of the disease 13 



Economic importance of the disease 14 



spraying for the control of peach brown-rot and scab in 1909 14 



Preparation of self-boiled lime-sulphur mixture 15 



Self-boiled lime-sulphur treatment and results 16 



Commercial results 17 



Self-boiled lime-sulphur and arsenate <>f lead in combination IS 



Commercial results 19 



Marketing test 20 



Cost of the treatment 21 



Danger of injury to the fruit and foliage 22 



Danger of staining the fruit 22 



Results obtained by growers in commercial orchards 23 



3 



