Weed competition in soybeans [Glycine max(L.) Merr. ‘Clark 63′] with planted stands of velvetleaf (Abutilon theophrastiMedic.), prickly sida (Sida spinosaL.), and Venice mallow (Hibiscus trionumL.) is reported. Weeds were planted 0, 10, 20, 30, and 40 days after soybeans and competed until soybeans matured. Soybean seed yields were reduced 720, 250, and 230 kg/ha by velvetleaf, Venice mallow, and prickly sida, respectively. Weeds that emerged with soybeans reduced yields 1,010 kg/ha. Weeds planted 10 days later reduced yields 480 kg/ha, but weeds planted 20 to 40 days after soybeans did not significantly reduced yield. Soybean yields were reduced regardless of weed placement in or between soybean rows. Weed competition reduced numbers of soybean pods per plant more than other soybean-yield components.

Competition studies were conducted with soybeansGlycine max.(L.) Merr. ‘Clark 63’ and Venice mallow (Hibiscus trionumL.). One Venice mallow per 7.5 cm of soybean row reduced soybean seed yield 632 kg/ha after 85 days competition. Thirty to 40-cm weed bands in and between soybean rows reduced yields 270 to 651 kg/ha with 35 to 40 days of competition. A natural stand of 215 Venice mallow plants per square meter reduced soybean yield 454 kg/ha after 30 days of competition, and competition up to 110 days reduced yield as much as 1490 kg/ha. Weed competition affected the number of pods per soybean plant more than any other seed-yield component, and soybean height was reduced. Soybean yields were reduced more when soil moisture was abundant early in the growing season and limited in late summer than when moisture was limited early in the growing season and above average until soybeans matured.

Associations among cattle stocking rate, precipitation, and eastern redcedar invasion, and possibly redcedar control measures were investigated. Redcedar numbers generally decreased as stocking rate increased. Precipitation had only a slight effect on invasion rate. Fire, cutting, and fenuron granules appear to effectively kill red cedar. Loamy upland range site consists of soils having medium-textured soil deep enough to support primarily big bluestem and Indiangrass in climax condition. Predominant slopes are 1 to 5%.

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