Manganese toxicity is most likely to be a problem under which soil conditions?
A) clay loam Ultisol, pH 4.3, subject to frequent flooding
B) well drained calcareous soil, pH 8.1
C) poorly drained calcareous soil with pH 7.6
D) muck soil (Saprist) with pH 5.5
E) well drained humid region loamy sand, pH 5.0
Question 2
Gypsum is the most widely used chemical for the reclamation of sodic soils. What characteristic likely accounts for this popularity?
A) Gypsum is quite insoluble so it remains in the soil for long periods of time.
B) Gypsum forms sulfuric acid that helps reduce the soil pH.
C) Gypsum provides sulfates that attract Na+ from the exchange complex.
D) Gypsum reacts with Na+ ions to form insoluble Na2SO4.
E) Gypsum is abundant and low priced.