Soil Characteristics Associated with a Primary Plant Successon on a Mojave Desert Dry Lake

Abstract

The playa of Rabbit Dry Lake has a fine—textured soil high in Na, Cl, and NO 3 but low in K and Ca + Mg. Kochia or sometimes Suaeda plants establish in mud cracks on the playa and accumulates small mounds of silty—sandy soil. High levels of NO 3 , Na, Cl, K, and Ca + Mg accumulate in soil of small mounds but decrease in playa—level soil under small mounds. Atriplex torreyi invades small mounds and accumulates large mounds of wind—deposited sandy soil. Continued increase of NO 3 and large increase of Na, Cl, K, and Ca + Mg occur in soil of large mounds as a result of Atriplex leaf deposition. Large mounds rapidly increase in size and coalesce to form giant mounds of sandy soil with levels of NO 3 , Na, Cl, K, and Ca + Mg sharply lower than those in large mounds but still higher than those in playa—level soil under the giant mounds. Soil of giant mounds is suitable for colonization by Atriplex confertifolia and Haplopappus acradenius. Following death of shrubs like Atriplex torreyi, giant mounds erode, and soil is deposited between eroding giant mounds at a level above the original playa. Such deposited soil is chemically similar to soil in giant mounds but Na and Cl are leached down to the playa level. The accumulation of soil and the redistribution of minerals by plants permit a primary plant succession to occur.