Simulated Acid Rain Effects on Jack Pine Seedling Establishment and Nutrition

Abstract

AbstractA greenhouse study examined the effects of simulated acid rain on jack pine (Pinus banksiana Lamb.) seedling development and the Grayling sand (Typic Udipsamments) growth medium. Five rain pH levels (2.0, 2.5, 3.0, 4.0, 4.7) and two soil horizons (A/E, Bw1) were included as levels of factors. Soil pH decreased only at rain pH 3.0 and below. Exchangeable Ca and Mg were reduced at pH 2.0 in A/E horizon soil only. Germination of jack pine was inhibited at pH 2.0 on both soils. Mortality of germinants was over 95% on both soils at pH 2.0, 42% on A/E soil at pH 2.5, and 2 to 13% in other treatment combinations. Seedling top weight increased and root weight decreased on both soils at pH 2.5. In seedlings grown at pH levels 2.5 to 4.7, tissue concentrations of N, K, Ca, Na, Mn, Zn, and Al increased, but P and Mg were reduced, as rain pH decreased. At pH 2.5, Al toxicity and deficiencies in P and Mg were indicated. Simulated rain approximating pH levels typical of precipitation in northern lower Michigan (> 3.0) did not adversely affect jack pine regeneration or soil properties of the Grayling sand during the 75‐d study.