Purple Nutsedge (Cyperus rotundus) Population Dynamics in Narrow Row Transgenic Cotton (Gossypium hirsutum) and Soybean (Glycine max) Rotation¹

Abstract

A 4-yr field study was conducted during 1998 through 2001 at Stoneville, MS, to determine the effects of narrow-row transgenic cotton and soybean rotation on purple nutsedge populations and crop yield. Crop rotations over 4 yr included cotton and soybean sown in the following patterns: CCSS, CSCS, SCSC, SSCC, and continuous cotton (CCCC) and soybean (SSSS), where cotton is denoted as (C) and soybean as (S), all with herbicide programs that were glyphosate based, non–glyphosate based, or no purple-nutsedge control (NPNC). Purple nutsedge populations and shoot dry biomass were reduced in cotton and soybean rotation and continuous soybean by 72 and 92%, respectively, whereas in continuous cotton, purple nutsedge populations increased by 67% and shoot dry biomass was reduced by 32% after 4 yr. Reductions in purple nutsedge populations also occurred in soybean when cotton was rotated with soybean (CSCS and SCSC), compared with continuous cotton. Among herbicide programs, the glyphosate-based program was more effective in reducing purple nutsedge populations, compared with the non–glyphosate-based program. Seed cotton yield was greater with cotton following soybean (SCSC) than with cotton following cotton (CCCC, CCSS) in 1999. However, seed cotton yields were similar regardless of crop rotation systems in 2000 and 2001. Seed cotton yields were equivalent in the glyphosate-based and non–glyphosate-based programs in 1999 and 2001. During 1999 to 2001, seed cotton yields were reduced by 62 to 85% in NPNC compared with yields in glyphosate- and non–glyphosate-based programs. Soybean yields were unaffected by crop rotation systems in all the 4 yr. Among herbicide programs, non–glyphosate-based program in all 4 yr and glyphosate-based program in 1999 and 2000 gave higher soybean yield compared with NPNC. After 4 yr of rotation, purple nutsedge tubers and plant density were highest in continuous cotton and lowest in continuous soybean. Both herbicide programs reduced tubers per core and plant density compared with NPNC, and the glyphosate-based program was more effective than the non–glyphosate-based program. These results show that in cotton production, severe infestations of purple nutsedge can be managed by rotating cotton with soybean or by using glyphosate-based herbicide program in glyphosate-resistant cotton.

Intercropping of field crops in cotton for the management of purple nutsedge (Cyperus rotundus L.)

“…In Pakistan, it is among the most common weeds found throughout the Indus valley during the summer season in major field crops such as cotton, sugarcane and maize. Bryson et al (2003) reported that purple nutsedge causes seed cotton yield reductions of 62-85%. It is difficult to control purple nutsedge effectively through usual weed control methods because of its specific biological characteristics, i.e.…”

Weed Interference in Zero-Till Cotton (Gossypium hirsutum L.)

“…The loss in the yield decreased with increase in the duration of weed free condition during the initial period of crop growth. [20]- [22] and [8] also reported that weeds reduced the cotton yield upto 85%. Seed cotton yield was adversely affected in plots maintained weed free only for 20, 40 and 60 days after sowing as compared to 80 DAS and weed infestation for 20 days after sowing or weed free treatments.…”

Maize–sorghum intercropping systems for purple nutsedge management

“…Tubers are present in chains of 15 or more and may have six or more buds, each of which is capable of sprouting (Edenfield et al 2005;Islam et al 2009). Purple nutsedge is highly competitive and may cause a decrease in field crop yields of 62-85% (Tuor and Froud-Williams 2002;Bryson et al 2003). It also interferes with crops by releasing allelopathic substances into the rhizosphere (Riemens et al 2008).…”