Diagnosing the Trouble. 343 
have still fallen baek 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, 
fill 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 TiruLAce Factor.—Soil texture. Fertility as influ- 
enced ly (a) fineness, (b) conditions of root-hold, (c) 
life processes, (d) air-holding capacity, (¢) water-holding 
eapacity. 
Sod in orehards Cover crops. 
to 
. THE FeErTILity Facror.— Our conceptions of the uses 
of nitrogen, potash, phosphoric acid, ete., in fruit-pro- 
duction. 
3. THE PrRuniING Factor.—The relation of pruning to wood- 
growth and fruit-growth. 
4. Tae Variety Facror.—(a) Unproductive varieties, ()) 
impotent varieties. 
5. THe Propagation Factor.—The individuality of the tree, 
and its power to perpetuate its characteristics. 
6. THE Parasite Facror.—(a) Fungi, (b) imseets.  Spray- 
ing (Chapter VII.). 
