Premium
Effects of Soil Moisture on Soil p CO 2 , Soil Solution Bicarbonate, and Iron Chlorosis in Soybeans
Author(s) -
Inskeep William P.,
Bloom Paul R.
Publication year - 1986
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1986.03615995005000040024x
Subject(s) - chlorosis , calcareous , soil water , water content , chemistry , moisture , soil science , agronomy , environmental science , geology , paleontology , geotechnical engineering , organic chemistry , biology
Abstract Four pot experiments were performed with five calcareous soils from western Minnesota (Haplaquolls and Calciaquolls) to determine the effects of soil moisture and soil temperature on Fe chlorosis in soybeans [ Glycine max (L.) Merr.]. We used a factorial design with gravimetric moisture contents and bulk density values ranging from 0.22 to 0.44 kg kg −1 and 1.14 to 1.38 Mg m −3 , respectively. Factor combinations of these levels resulted in ranges of volumetric moisture contents from 0.27 to 0.54 m 3 m −3 , air filled porosity fractions from 0.27 to 0.00, and soil matric potentials from <‐1500 to near 0 kPa. The soil p CO 2 contents measured from gas wells in pots increased from 0.16 to 1.64 cmol mol −1 as a result of decreased gas diffusion when the air‐filled porosity decreased. With increasing soil moisture, soil solution HCO ‐ 3 concentrations attained values as high as 10 m M . Total chlorophyll (Chl T ) contents of Anoka soybeans decreased as soil moisture, soil p CO 2 , and soil solution HCO ‐ 3 increased. The same response was not observed in all calcareous soils. Calcareous soils with lower amounts of clay sized CaCO 3 , lower soil solution Mg 2+ , and/or lower bicarbonate extractable P did not produce as severe a chlorosis with increased moisture. This suggests that clay sized CaCO 3 , Mg, or P may be additional stress factors associated with HCO ‐ 3 induced chlorosis. High soil moisture treatments on a calcareous soil provided an effective soil screen for differentiating between susceptible and nonsusceptible soybean cultivars. Soil temperatures of 12 and 26°C produced more chlorosis at a given soil moisture than at 16 or 19°C. Soil temperature appears to be an additional stress factor, which might explain some of the variability in the incidence of Fe chlorosis under field conditions.