xx CONTENTS 



PAGB 



The relation of fallowing to soil fertility .... 296 



An ancient practice ....... 296 



Fallowing to store water ...... 297 



Fallowing to set free plant food ..... 297 



Fallowing to destroy weeds ..... 298 



The methods of fallowing 298 



Rotation of crops ........ 299 



Nature's rotations ....... 300 



Why a rotation is beneficial ...... 300 



It affects the relative supply of plant foods . . .301 

 The different rooting habits of crops . . . .301 



Rotations and' weediness ...... 302 



Injurious insects and diseases lessened . . . 303 

 Keep the soil busy ....... 304 



Economy of labour ....... 304 



Choosing crops for a rotation ...... 305 



Typical systems of rotations . . . . . . 307 



Single-crop farming . . . . . . .310 



Selling fertility . 311 



A bank account with the soil of fanning . . .312 



Loss of plant food in different systems . . .312 



Advantages of diversified farming . . . . .315 



Keeping live-stock to maintain fertility . . . .316 



The excretory theory of soil fertility . . . . .318 



CHAPTER XII. GREEN-MANURING AND 

 WORN-OUT SOILS 



What is meant by "good texture" 322 



How Nature secures good texture . . . . . 323 



How humus benefits the soil ...... 327 



By improving its texture ...... 327 



By increasing its power to hold water .... 828 



By enriching it . . . . . . . . 328 



The kinds of green-manures ...... 329 



Leguminous ........ 329 



Non-leguminous ....... 330 



When a green-manuring crop may be grown . . . 330 



In a rotation ........ 331 



Catch crops and cover crops . . . . .331 



The fertilising value of roots and stubble .... 332 



Green-manures not complete fertilisers . . . 332 



