114 CHAPTER VII 



corns as well as some of the saccharine sorghums do well under 

 conditions preferred by maize rather than those must suitable 

 for the non-saccharine kinds. In the United States of America 

 the average annual rainfall for the Grain Sorghum belt is about 

 20 inches, varying in different parts from 15 to 25 inches, the 

 majority of which falls in the growing season, and the evapora- 

 tion is from 35 to 55 inches. 



They are extremely sensitive to frosts, but their water 

 requirement is less than that of maize. 



Soils. — In general, soils suitable for maize are suitable 

 for sorghums, although good forage crops are grown on soils 

 too poor for maize. They are supposed to be much more 

 alkali-resistant than maize. Being comparatively surface 

 feeders, they have the reputation of being very exhaustive of 

 soil fertility. In reality this is not so, since suitable rotations 

 will maintain the yield. 



In semi-arid parts the soils are usually vei-y poor in humus, 

 consequently to increase the water-holding and water- 

 absorbing capacity of the soil rotations should be judiciously 

 planned to increase or maintain the humus content when 

 economically possible. 



Soil Preparation. — This is very similar to that required 

 by maize, but as the seedlings are less vigorous than those of 

 maize the surface should be reduced to a finer tilth. Deep 

 ploughing in sorghum areas is not always advisable, as it may 

 result in excessive desiccation of the soil and subsoil, which 

 is in most cases harmful. The object should be to keep the 

 soil free from weeds, and in a receptive condition for rain. 

 Ploughing and leaving the ground rough until just before 

 planting is sufficient. Just previous to planting the ground 

 should be worked down into a moderately fine tilth. On some 

 soils, though, deep ploughing has proved necessary. 



Very sandy soils are common in the sorghum areas, and 

 on these care should be exercised to prevent blowing. Humus 

 is particularly important, and every means of incorporating it 

 economically should be resorted to. If free from weeds, the 

 soil should be left undisturbed as long as possible. On these 

 soils American experience indicates that listing is preferable 

 to ploughing, as the soil is disturbed less. 



Seed. — This weighs 64 to 62 pounds per bushel. When 

 a variety has been found suitable to a particular part 

 that variety should be adhered to, and selection should be 

 made from the desirable plants before the whole crop is har- 

 vested. As the seed of sorghums grown under uncertain con- 



