Effects of foliar and soil acidity on the rhizospere pH of alfalfa, corn and soybean. [Medicago sativa, Zea mays, Glycine max L]

Journal Article · · Journal of Environmental Quality; (United States)

OSTI ID:5196499

Conkling, B L ^[1]; Blanchar, R W; Niblack, T L ^[2]

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1. Univ. of Nevada, Las Vegas (USA)
2. Univ. of Missouri, Columbia (USA)

The acidity of ambient rainfall and its effect on soil and plants is a growing concern. Glass microelectrodes were used to investigate the effect of soil pH and foliar application of acid rain on the rhizosphere pH of alfalfa (Medicago sativa L. cv. Arrow), corn (Zea mays L. cv. B72 {times} MO17), and soybean (Glycine max (L.) Merr. cv. Williams 82). Plant roots were grown in minirhizotrons containing a reformed sample of Seymour silt loam A horizon over a silty clay loam Bt horizon. Low and high pH levels of 4.9 and 6.2 in the A horizon and 4.0 and 5.7 in the Bt horizon were established using dilute sulfuric acid or calcium ozide, respectively. Palnts received daily applications of simulated rain, which was either acid (pH 3.1) or non-acid (pH 5.6). After 5,6, or 15 d of foliar applications to corn, soybean, or alfalfa, respectively, the rhizosphere pH was measured using a glass microelectrode. The pH values for corn and soybean increased with distance from the root while the pH values for alfalfa decreased with distance. As the soil pH increased from 4 to near 6, the difference between the pH at the root surface and the bulk soil increased from 0 to near 1. A trend for lateral root pH values at all distances to be slightly higher than main roots was observed. Increasing the pH of the A horizon had no significant effect on the rhizospehre pH of corn roots growing in the Bt horizon, but significantly increased soybean rhizosphere pH in the Bt horizon. Acid rain applications caused foliar damage, and tended to decrease rhizosphere pH, but few effects were significant.

• OSTI ID: 5196499
• Journal Information: Journal of Environmental Quality; (United States), Vol. 20:2; ISSN 0047-2425
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
54 ENVIRONMENTAL SCIENCES
ACID RAIN
ENVIRONMENTAL EFFECTS
ALFALFA
GLYCINE HISPIDA
MAIZE
PH VALUE
ROOTS
SIMULATION
SOILS
ATMOSPHERIC PRECIPITATIONS
CEREALS
GRAMINEAE
LEGUMINOSAE
LILIOPSIDA
MAGNOLIOPHYTA
MAGNOLIOPSIDA
PLANTS
RAIN
560300* - Chemicals Metabolism & Toxicology
540120 - Environment
Atmospheric- Chemicals Monitoring & Transport- (1990-)