480 FIELD CROPS 



seldom destructive to all crops in any one year. The diversi- 

 fication of crops has been the best means of preventing finan- 

 cial disaster in the sections of the South which have been 

 invaded by the cotton boll weevil, just as it has been under 

 similar circumstances in other sections. 



657. Rotations Increase Crop Yields. One crop helps 

 to prepare the soil for the one which follows. Clover opens 

 the subsoil and adds nitrogen and vegetable matter for the 

 corn or potato crop which comes after it. A cultivated crop 

 preceding one of small grain puts the soil in the best physical 

 condition, conserves moisture, and cleans the land of weeds. 

 If the crops which are produced are largely fed on the farm 

 and the manure returned to the land, crop yields will be 

 further increased, because each crop, except perhaps the small 

 grains, increases the available supply of plant food. The 

 grasses and clovers add vegetable matter to the soil, while 

 cultivation unlocks a part of the store of plant food and 

 makes it available for the use of plants. 



658. Rotations Distribute Farm Labor. Growing a 

 single crop or a single class of crops limits the seasons at 

 which farm work can be done. The growing of small grains 

 requires a rush of work during a few weeks while the land is 

 being prepared and the crops seeded, and again during har- 

 vest, with little employment during the remainder of the 

 year. Cultivated crops in general are planted later than the 

 small grains and most of the work of cultivation is done 

 before grain harvest, while they are not ready to gather until 

 the grain crops are safely housed. Hay crops require little 

 labor except at the haying season, which usually comes when 

 other crops do not require much attention, except that it may 

 sometimes conflict with the harvest of small grains, or the 

 cultivation of intertilled crops. The harvest of such crops 

 as alfalfa, which yield several cuttings during the season, 

 may conflict with the handling of other crops, but such con- 

 flicts can hardly be avoided. A diversity of crops usually 



