Diagnosing the Trouble. 343 



have still fallen back upon the fundamental prin- 

 ciples of land management, and have said that the 

 system is nevertheless wrong. Time is rapidly 

 demonstrating the accuracy of their prophecies. It 

 is a case in which a handful of philosophy is worth 

 more than a forkful of facts. 



If one asks why orchards are barren, let him 

 till out the following synopsis by way of review of 

 some of the principles which are enunciated in this 

 book : 



The nature of the problem: each case must be investi- 

 gated by itself; teaching must be along the line of general 

 or fundamental principles, not statements of rules. The six 

 general factors which determine productiveness are: 



1. THE TILLAGE FACTOR. Soil texture. Fertility as influ- 

 enced by (a) fineness, (M conditions of root-hold, (c) 

 life processes, (d] air-holding capacity, (e) water-holding 

 capacity. 



Sod in orchards Cover crops. 



2. THE FERTILITY FACTOR. Our conceptions of the uses 

 of nitrogen, potash, phosphoric acid, etc., in fruit-pro- 

 duction. 



3. THE PRUNING FACTOR. The relation of pruning to wood- 

 growth and fruit -growth. 



4. THE VARIETY FACTOR. (a) Unproductive varieties, (ft) 

 impotent varieties. 



5. THE PROPAGATION FACTOR. The individuality of the tree, 

 and its power to perpetuate its characteristics. 



6. THE PARASITE FACTOR. (a) Fungi, (b) insects. Spray- 

 ing (Chapter VII.). 



