So-called “alkali” spots are frequently found on farms located in north central Iowa on the Wisconsin drift soil area. They vary from one-tenth of an acre to two acres or more in size and are unproductive because of an accumulation of excessive amounts of salts. They appear in fields otherwise satisfactorily productive and reduce considerably the value of the land. They are characterized by the appearance of a whitish deposit of salts on the surface of the soil and by a stunted and unsatisfactory growth of corn and of many other crops.
The cause and origin of these “alkali” spots and the character of the salts present have been discussed in another bulletin^. They occur in connection with swales, ponds or sloughs which have been recently drained. They are not found in the lower parts of. the sloughs but always in a belt around the low spot, appearing after such an area has been drained.
Bancroft, Ross L.
"The “alkali” soils of Iowa,"
Bulletin: Vol. 15
, Article 1.
Available at: https://lib.dr.iastate.edu/bulletin/vol15/iss177/1