94 The Principles of Vegetable- Gardening 



(1) it gives different treatments to the land, the fault 

 of one year tending to be corrected by the manage- 

 ment in another year; (2) no one element of plant -food 

 is exhausted, the rotation tending to even up the 

 demands on the soil; (3) one crop leaves the land 

 in good physical condition for another ; (4) it incor- 

 porates humus; (5) it destroys pests and weeds; (6) 

 it economizes labor; (7) when green crops are turned 

 under, available or digested plant -food is incorporated 

 with the soil, and nitrogen may be supplied. The rota- 

 tion of crops means, also, rotation in tillage, manuring 

 and other treatment ; and one of these may be quite as 

 important as the other. 



The philosophy of the resting'^ of land is hereby 

 explained. It is not due to any need of recuperation 

 in the soil ; but the good effects which follow are the 

 compound results of the various benefits which are 

 derived from tilling and rotation. Gardeners find that 

 when soil becomes unproductive for a particular crop, 

 a change to some other crop may result in profit. 

 Soils which have been long kept in market-gardens may 

 be benefited by seeding down for two or three years. 

 Whenever possible, attempts should be made to prac- 

 tice some kind of a rotation in the market-garden area. 

 Now and then, a part of the land may be laid down to 

 clover for a year or two. 



2. THE FERTILIZING OF THE LAND 



When the soil has been thoroughly fitted and im- 

 proved by all the foregoing means, a gardener may 



