Row Width and Weed Management Systems for Conventional Soybean Plantings in the Midsouthern USA

Abstract

Field studies were conducted from 1994 through 1996 on Sharkey clay (very fine, smectitic, thermic chromic Epiaquert) at Stoneville, MS (33°26′N lat) to determine effect of weed management treatment (WTRT) on yield and net return from Maturity Group V soybean [Glycine max (L.) Merr.] cultivars differing in height and grown in narrow rows (NRs; 50‐cm width) and wide rows (WRs; 100‐cm width) without and with irrigation. The WTRTs were (i) pre‐emergence (PRE) and postemergence (POST) broadleaf weed management; (ii) PRE broadleaf, PRE grass, and POST broadleaf weed management; (iii) POST broadleaf weed management; and (iv) POST broadleaf and POST grass weed management. Herbicides were broadcast‐applied in NRs and band‐applied (0.5‐m‐wide band centered over each row) in WRs. Postemergent cultivation was conducted in WRs. Weed management expense for NRs was greater than that for WRs in most cases. Use of NRs vs. WRs resulted in less weed cover at the end of the growing season, regardless of cultivar or WTRT. Three‐year average seed yield and net return from NRs were greater than those from WRs. Regardless of row width, cultivar, or irrigation environment, highest net returns were obtained from managing only broadleaf weeds either PRE or POST under the conditions at this site.