COX T E X T S. 
Tage. 
Introduction 7 
Section T.— Soil sampling - - 10 
Section II.— The Broadbalk wheat soils 18 
Summarized history 12 
Mechanical composition (stones, fine soil, etc.) 14 
Samples taken in 18W 25 
Total nitrogen and organic carbon (general discussion and full state- 
ment of analytical results) 85 
Total nitrogen in unmanured and in continuously dunged plats. 38 
The two dunged plats | 8a and >b) 39 
Rape-cake plat ... 40 
The chemically manured plats . 41 
Plat fi t mineral manures only ) 41 
General comparison of all chemically manured plats .. 42 
Plats 5 to 8 (all fully supplied with mineral manures, but receiving 
different dressings of ammonium salts) 46 
Plats 10a. 1 L, 18, 7 (all receiving like dressings of ammonium salts, 
but differing in mineral treatment) . .. 47 
Nitrogen accumulations as crop residue 48 
Loss of nitrogen 49 
Nitrogen and carbon in subsoils. 50 
Carbon and ratio of carbon to nitrogen 51 
Nitrogen contents of various other Rothainsted soils . . . _ 68 
Nitrogen and carbon in other clays and deep deposits 59 
Nitrogen as nitrates ( * 1 nitric " nitrogen ) 01 
General discussion and full statement of analytical results on the 
Broadbalk soils . 01 
Does nitrification occur in the lower subsoils ? - 05 
Nitric nitrogen in the unmanured and the dunged plats and the 
rape-cake plat 67 
The chemically manured plats 69 
Comparison of plats receiving ammonium salts and sodium nitrate, 
respectively 72 
Comparison of plats receiving like dressings of ammonium salts, 
but with varying mineral treatment 74 
How far do the nitrates found account for nitrogen lost? 70 
Chlorin 78 
General discussion and full statement of analytical results - 78 
Chlorin in crops 84 
Action of ammonium salts on the lime of the soil 80 
5 
