Establishment of Early Successional Plant Populations on Forest and Prairie Soil

Abstract

Seed germination and plant community development on adjacent forest and prairie soils (Typic Hapludalf and Typic Halplaquoll) were studied to elucidate the causes of variation in plant community composition during the first growing season after crop harvest. The number of plant individuals in July on the forest soil was three times larger than on the prairie soil. Abutilon theophrasti, Chenopodium album, Polygonum pensylvanicum, and Setaria faberii occurred in large numbers on the forest soil but were considerably less important on the prairie soil. Ipomoea hederacea predominated on the prairie soil. The seed load after abandonment on the forest soil was larger than on the prairie soil both before and after overwintering. Total numbers of plants that reached maturity were significantly higher (at the 5% level) on the forest soil than on the prairie soil. Population levels were generally constant throughout the growing season. Diversity peaked in June and was higher on the prairie soil than on the forest soil throughout the growing season. Germination of Ambrosia artemisiifolia, Lactuca scariola, and Polygonum was enhanced by moist soil conditions, whereas germination of Amaranthus hybridus was higher under dry soil conditions. Lactuca and Polygonum were the most sensitive to water stress and Abutilon and Setaria the most tolerant. It appears that the kinds and numbers of plants that become established in an abandoned field are a function of the number of germinable seeds present in the soil and the seed—soil water relationships. Of the soil parameters that may control seed germination, there is strong evidence to suggest that soil moisture the extreme upper portion of the profile is the major factor.