Palmer Amaranth (Amaranthus palmeri) Competition for Water in Cotton

Abstract

Palmer amaranth is a troublesome weed in cotton production. Yield losses of 65% have been reported from season-long Palmer amaranth competition with cotton. To determine whether water is a factor in this system, experiments were conduced in 2011, 2012, and 2013 in Citra, FL, and in Tifton, GA. In 2011, infrequent rainfall lead to drought stress. The presence of Palmer amaranth resulted in decreased soil relative water content up to 1 m in depth. Cotton stomatal conductance (gs) was reduced up to 1.8 m from a Palmer amaranth plant. In 2012 and 2013 higher than average rainfall resulted in excess water throughout the growing season. In this situation, no differences were found in soil relative water content or cottongsas a function of proximity to Palmer amaranth. A positive linear trend was found in cotton photosynthesis and yield; each parameter increased as distance from Palmer amaranth increased. Even in these well-watered conditions, daily water use of Palmer amaranth was considerably higher than that of cotton, at 1.2 and 0.49 g H20 cm−2d−1, respectively. Although Palmer amaranth removed more water from the soil profile, rainfall was adequate to replenish the profile in 2 of the 3 yr of this study. However, yield loss due to Palmer amaranth was still observed despite no change ings, indicating other factors, such as competition for light or response to neighboring plants during development, are driving yield loss.

Evaluating Effect of Degree of Water Stress on Growth and Fecundity of Palmer amaranth (Amaranthus palmeri) Using Soil Moisture Sensors

“…J. D. Sauer], and redroot pigweed ( Amaranthus retroflexus L.) are the most commonly found Amaranthus species in Nebraska agronomic crop fields (Vieira et al 2018); however, they differ in their growth characteristics (Horak and Loughin 2000). Amaranthus palmeri has the highest plant dry weight, leaf area, height, growth rate (0.10 to 0.21 cm per growing degree day), and water-use efficiency compared with other pigweed species (Berger et al 2015; Horak and Loughin 2000; Massinga et al 2003; Wiese 1968). Amaranthus palmeri roots are finer, longer, and greater in number, allowing it to occupy a much larger soil volume and acquire more soil nutrients compared with most crops, especially during conditions of water stress and low fertility (Wright et al 1999a).…”

Overlapping Residual Herbicides for Control of Photosystem (PS) II- and 4-Hydroxyphenylpyruvate Dioxygenase (HPPD)-Inhibitor-Resistant Palmer amaranth (Amaranthus palmeri S. Watson) in Glyphosate-Resistant Maize

“…Palmer amaranth biotypes with multiple resistance to two or more herbicide sites of action have also been confirmed (Sosnoskie et al, 2011 ; Nandula et al, 2012 ; Heap, 2017 ). Palmer amaranth's aggressive growth habits and prolific seed production along with its evolution of resistance to different herbicide sites of action has made it the most problematic crop weed in the USA (Horak and Loughin, 2000 ; Berger et al, 2015 ; Chahal et al, 2015 , 2017 ; Kohrt and Sprague, 2017 ).…”

Differentiation of Life-History Traits among Palmer Amaranth Populations (Amaranthus palmeri) and Its Relation to Cropping Systems and Glyphosate Sensitivity

“…The troublesome nature of Palmer amaranth in multiple cropping systems is mainly attributed to its ability to compete highly for resources such as water, nutrients, and light (Berger et al 2015b; Massinga et al 2003; Ruf-Pachta et al 2013). Furthermore, characteristics such as diaheliotropism and a C 4 photosynthetic pathway allow Palmer amaranth to quickly accumulate biomass compared with non–solar tracking weed species (Ehleringer 1983; Gibson 1998).…”