CHAPTEB Y. 



THE SYSTEM OF FARM-YARD MANURING. 



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

 unmanured fields Influence of preceding crops, of the situation, and climatic 

 conditions, on the produce Each field possesses its own power of production 

 Large crops, their dependence and continuation 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 produce Produce of corn and straw influenced by 

 the relations of the assimilated food and by the conditions of growth ; action 

 of food supplied 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 cal- 

 culated from the amount of manure used Restoration of the power of produc- 

 tion of exhausted fields by the increase of the necessary elements of food pre- 

 sent in the soil in minimum amount ; advantageous use of farm-yard manure 

 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 

 eoil ; the Saxon fields considered in this respect ; the power of absorption con- 

 sidered in manuring Change produced in the composition of the soil by tho 

 system of farm-yard manuring; the different stages of this system, the final 

 result Examples of these stages in the Saxon experimental fields Cause of 

 the growth of weeds ; remedies The history of husbandry, what is taught by 

 it Present condition 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 Agriculture 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 agriculture and thelaw of restoration The statistical 

 returns of average crops afford an explanation 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 

 investigation of all those phenomena which are pre- 

 sented^by the practice of farm-yard manuring. We 

 have to consider how farm-yard manure increases the 

 produce of a field ; on which constituents of the 

 manure its action depends ; what quantity of farm-yard 

 manure can be obtained from a field ; and to what con- 



