102 WHEAT 



WHEAT SICK LAND 



Fertile land which has been cropped with wheat 

 for a long time becomes "wheat sick." It is not 

 necessarily exhausted in fertility it needs a rest, 

 a change of crop. The soil is likely to become 

 exhausted in nitrogen and organic matter and 

 humus, and it may become deficient in some of 

 the mineral elements of plant food. But the prob- 

 lem of reduced yields is not a matter of plant food 

 alone. The continuous cropping with wheat 

 infects the soil with plant diseases and injurious 

 insects, and the loss of organic matter and con- 

 tinuous tillage destroys the ideal texture and tilth 

 which characterized the virgin prairie when it 

 was first broken. What the old wheat land needs 

 worst and first is a proper rotation of crops which 

 will serve to aerate the soil and free it of weeds 

 and infectious diseases and injurious insects, and 

 at the same time renew the supply of organic 

 matter and nitrogen. 



ROTATION PLANS 



In planning rotations, four general classes of 

 crops should be provided for if conditions will 

 allow: 



1. A "money" crop, or crop to be sold, which 

 may remove from the soil considerable quantities 

 of plant food. 



2. A leguminous crop to return nitrogen and 

 organic matter to the soil, and also by its deep 

 root system to collect subsoil phosphorus, potas- 

 sium and lime. 



