Soil Moisture Effects on Competitive Ability of Weeds

Abstract

Ten plant species were grown in competition with each other at different soil moisture levels in a greenhouse. Corn (Zea mays L.), barnyardgrass (Echinochloa crusgalli (L.) Beauv.), cocklebur (Xanthium pensylvanicum Wallr.), sorghum (Sorghum vulgare L., var. RS 626), and large crabgrass (Digitaria sanguinalis (L) Scop.) produced the most growth in wet soil. Dry soil greatly reduced growth of these species. Palmer amaranth (Amaranthus palmeri S. Wats.) produced an intermediate amount of growth under wet and medium soil moisture and much less in dry soil. Kochia (Kochia scoparia (L.) Schrad.), Russian thistle (Salsola kali L., var. tenuifolia Tausch), buffalobur (Solanum rostratum Dunal.), and tumble-grass (Schedonnardus paniculatus (Nutt.) Trel.) produced much less growth under wet conditions than the more competitive species, but growth was not reduced in dry soil. Russian thistle produced twice as much growth in dry as in wet soil.