Limited effects of soil nutrient heterogeneity on populations of Abutilon theophrasti (Malvaceae)

• Published in: American journal of botany 1996-03, Vol.83 (3), p.333-341
• Main Authors: Casper, B.B. (University of Pennsylvania, Philadelphia, PA.), Cahill, J.F. Jr
• Format: Article
• Language: English
• Subjects: ABUTILON THEOPHRASTI; Agricultural soils; ALTURA; ANALISIS CUANTITATIVO; ANALYSE QUANTITATIVE; ANATOMIA DE LA PLANTA; ANATOMIE VEGETALE; ANCHURA; BIOMASA; Biomass; Biomass production; BIOMASSE; BOTANICA; BOTANIQUE; Botany; CHIMIE DU SOL; COMMUNAUTE VEGETALE; COMUNIDADES VEGETALES; COUVERT; CRECIMIENTO; CROISSANCE; CUBIERTA DE COPAS; DISPONIBILIDAD DE NUTRIENTES; DISPONIBILITE D'ELEMENT NUTRITIF; Ecology; ESTRUCTURA DE LA POBLACION; FEUILLE; Flowers & plants; HAUTEUR; HOJAS; LARGEUR; MALEZAS; Malvaceae; MAUVAISE HERBE; Plant growth; Plant nutrition; Plants; POBLACION VEGETAL; Population size; population structure; POPULATION VEGETALE; QUIMICA DEL SUELO; Soil ecology; Soil heterogeneity; soil nutrient heterogeneity; Soil nutrients; Soil treatment; Soils; STRUCTURE DE LA POPULATION; VARIACION GENETICA; VARIATION GENETIQUE; weedy annual
• ISSN: 0002-9122; 1537-2197
• DOI: 10.1002/j.1537-2197.1996.tb12714.x

An experiment was conducted to determine if spatial nutrient heterogeneity affects mean plant size or size hierarchies in experimental populations of the weedy annual Abutilon theophrasti Medic. (Malvaceae). Heterogeneity was imposed by alternating 8 X 8 X 10 cm blocks of low and high nutrient soil in a checkerboard design, while a homogeneous soil treatment consisted of a spatially uniform mixture of the two soil types (mixed soil). Populations were planted at three densities. The effect of soil type on the growth of individuals was determined through a bioassay experiment using potted plants. The high nutrient, low nutrient, and mixed soil differed in their ability to support plant growth as indicated by differences in growth rates and final aboveground biomass. Concentrations of N, K, P, and Mg, measured at the end of the growing season in the experimental plots, also differed among all three soil types. Nevertheless, nutrient heterogeneity had little effect at the population level. Mean maximum leaf width measured at midseason was greater for populations on heterogeneous soil, but soil treatment did not affect midseason measurements of plant height, total number of leaves per plant, or canopy width. Population density affected all these parameters except plant height. When aboveground biomass was harvested at the end of the growing season, soil treatment was found to have no main effect on mean plant biomass, total population biomass, the coefficient of variation in plant biomass, or the combined biomass of the five largest plants in the population, but mean plant biomass was greater for populations on heterogeneous soils at the intermediate planting density. Mean plant biomass, total population biomass, and the coefficient of variation in plant biomass all varied with planting density. Mortality was low overall but significantly higher on homogeneous soil across all three densities. Soil heterogeneity had its strongest effect on individuals