Shading Response of Solanaceous and Amaranthaceous Weeds in Soybean
The ability of emerged seedlings of apple of Peru [Nicandra physalodes (L.) Gaertn], cutleaf groundcherry (Physalis angulata L.), eastern black nightshade (Solanum ptycanthum Dunal), and two biotypes of Palmer amaranth [Amaranthus palmeri (S.) Wats.] to withstand canopy shading under 25- and 45-cm soybean [Glycine max (L.) Merr.] height was investigated in the greenhouse. Weeds and soybean were grown in separate pots to prevent competition for water and nutrients and to eliminate the possibility of chemical interactions through allelopathy. Weed dry weight was reduced 40 to 81% when planted with the 45-cm-tall soybean but no more than 14% when planted with 25-cm-tall soybean. Cutleaf groundcherry and eastern black nightshade biomass were affected less by soybean than Palmer amaranth biotypes and apple of Peru when grown with 45-cm soybean but weed biomass reduction did not differ among weed species in the soybean 25-cm shade.
Stark, Allison M., Michael G. Burton, David L. Jordan, Robert J. Richardson, Janet F. Spears, and Steve T. Hoyle. "Shading Response of Solanaceous and Amaranthaceous Weeds in Soybean." Crop Management 11, no. 1 (2012).