188 



CHAPTEE V. 



THE SYSTEM OP FAEM-YARD MANURING. 



Questions to be solved — Experiments of Kenning, their significance — 

 Produce of unmauiu-ed fields — Infiuence of preceding crops, of the situ- 

 ation, and climatic conditions, on the produce — Each field possesses its 

 own power of production — Large crops, their dependence and continua- 

 tion — Closeness of the food of plants, what is meant thereby — The 

 closeness of the particles of food in the soil is in proportion to the pro- 

 duce — Produce of corn and straw influenced by the relations of the 

 assimilated food and by the conditions of growth ; action of food sup- 

 plied in manures — Potatoes, oats, and clover crops of the Saxon fields ; 

 conclusions drawn from them as to the condition of the fields — Produce 

 of these fields from farm-yard manure ; the increase of produce cannot be 

 calculated from the amount of manure used — Restoration of the power of 

 production of exhausted fields by the increase of the necessai-y elements of 

 food present in the soil in minimum amount; advantageous use of farm-yard 

 manm-e in this respect; explanation of the result — Action of manure as 

 compared with quantity used : experiments — Rational system of cultivation 

 — Depth to which the food of plants penetrates is dependent on the power 

 of absorption of the soil; the Saxon fields considered in this respect; the 

 power of absorption considered in manuring — Change produced in the 

 composition of the soil by the system of farm-yard manuring ; the dif- 

 ferent stages of this system, the final result — Examples of these stages in 

 the Saxon experimental fields — Cause of the growth of weeds ; reme- 

 dies — The history of husbandry, what is taught by it — Present condi- 

 tion of European husbandry — Present production of the land compared 

 with the earlier ; conclusions — Continuation of production regulated by 

 a natural law — Law of restoration ; defective practice of it — Agricul- 

 ture in the time of Charlemagne — Agriculture in the Palatinate — Corn 

 fields in the valleys of the Nile and Ganges ; nature provides in them for 

 the restoration of food of plants — Practical agricultm-e and the law of 

 restoration — The statistical returns of average crops afford an explana- 

 tion of the condition of corn fields. 



THE general observations in the preceding chapters 

 on the mutual relations between the soil and plants, 

 as also on the sources and nature of farm-yard manure, 

 will, I hope, enable the reader to enter upon a thorough 



