Accession Number : ADA195125

Title :   The Effect of Acid Deposition on Potentially Sensitive Soil-Plant Systems at Vandenberg AFB, California.

Descriptive Note : Final rept. 1 Sep 84-1 Sep 87,

Corporate Author : SAN DIEGO STATE UNIV CA DEPT OF BIOLOGY

Personal Author(s) : Zedler, Paul H ; Marion, Giles

PDF Url : ADA195125

Report Date : 30 Apr 1988

Pagination or Media Count : 162

Abstract : The objectives of this study were to assess the impact of the acid deposition expected from rocket launches on natural coastal vegetation and soils. Interest was directed primarily toward the longer-term and more subtle effects of acidity, and the degree of sensitivity of different soil-plant systems. A study area was established along a topographic chronosequence that ranged from stabilized dunes to residual soils over bedrock. Soils and plants were collected from this region and used in three main studies. A leaching study measured the changes in chemical properties of four soils subjected to repeated acid additions. A second study treated seeds of wide variety of native or spontaneous species with HC1 on the four soils to establish the sensitivity of the vegetation to deposition events during the fall to winter germination pulse characteristic of California coastal ecosystems. A third study examined the effect of acid treatments on the growth of and competition between two common woody plants -- Artemisia californica and Pinus muricata. A fourth study partially supported by this grant studied the invasion of an exotic species in a recently burned site on one of the four study soils. The studies collectively show that although the soil-plant systems are well buffered against moderate and low inputs of acidity, the effect of acid additions differed among soil types and from species to species. Overall the hypothesis that acidic deposition could affect plant-plant and soil-plant interactions was supported, but some of these effects are subtle and not all appear to be deleterious.

Descriptors :   *ACID DEPOSITION, *PLANTS(BOTANY), *SOILS, *ROCKET LAUNCHING, ACIDS, CALIFORNIA, CHEMICAL PROPERTIES, COASTAL REGIONS, DEPOSITION, DUNES, ECOSYSTEMS, GERMINATION, HYPOTHESES, INTERACTIONS, LEACHING, PULSES, RESIDUALS, SENSITIVITY, STABILIZATION, VEGETATION, WINTER, AIR FORCE FACILITIES, GEOCHEMISTRY, SEEDS, HYDROCHLORIC ACID, AUTUMN, PLANT GROWTH, SHRUBS, TREES, ENVIRONMENTAL IMPACT

Subject Categories : Soil Mechanics
      Water Pollution and Control
      Ecology

Distribution Statement : APPROVED FOR PUBLIC RELEASE