Anatomical adaptations to different soil moisture contents in palisade grass and smooth pigweed

ABSTRACT Weed adaptations to different environments contribute to their success in establishing in different agroecosystems. A greenhouse and laboratory study was carried out to evaluate the effects of different levels of soil moisture on the anatomical characteristics of two weed species. The treatments were arranged in a 2 x 5 factorial design, with the first factor representing the weed species (Amaranthus hybridus and Brachiaria brizantha) and the second factor being the soil moisture levels in which they were grown (100%, 80%, 74%, 67%, and 60% of field capacity). At 55 days after weed emergence, the material for anatomical evaluations was collected. The water stress affected the two weed species differently, causing changes both in the thickness of the tissues evaluated and in their proportions. These changes seem to be related to how each species tolerates water stress. A. hybridus showed thickening of all leaf tissue and change in the proportion of these tissues, whereas B. brizantha showed a decrease in thickness of the leaf tissue and an increase in the proportion of adaxial epidermal and parenchymal tissues.

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Effect of water on common lambsquarters (Chenopodium album L.) and barnyardgrass [Echinochloa crus-galli (L.) Beauv.] seedling emergence in corn

Canadian Journal of Plant Science ◽

10.4141/p01-195 ◽

2002 ◽

Vol 82 (4) ◽

pp. 855-859 ◽

Cited By ~ 5

Author(s):

M. L. Leblanc ◽

D. C. Cloutier ◽

C. Hamel

Keyword(s):

Soil Moisture ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Chenopodium Album ◽

Seedling Emergence ◽

Field Capacity ◽

Emergence Period ◽

Common Lambsquarters ◽

Weed Emergence

A 2-year field study was conducted in corn to determine the influence of rainfall, irrigation and soil water content on common lambsquarters and barnyardgrass emergence. Rainfall or irrigation had no influence on the final weed density and little on the pattern of weed emergence because the soil water content was at or greater than field capacity during the main weed emergence period. Irrigation may hasten the first weed emergence by warming the soil when temperature is limiting for germination. In southwestern Quebec, temperature appears to be the most important factor regulating germination in the spring since soil moisture is normally at field capacity for a long period, in part because of the melting of snow. Key words: Irrigation, weed emergence, soil moisture

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Phosphorus effects on competitive interactions of smooth pigweed (Amaranthus hybridus) and common purslane (Portulaca oleracea) with lettuce (Lactuca sativa)

Weed Science ◽

10.1017/s0043174500089463 ◽

1998 ◽

Vol 46 (3) ◽

pp. 307-312 ◽

Cited By ~ 17

Author(s):

Bielinski M. Santos ◽

Joan A. Dusky ◽

William M. Stall ◽

Donn G. Shilling ◽

Thomas A. Bewick

Keyword(s):

Competitive Ability ◽

Organic Soils ◽

Weed Species ◽

Population Densities ◽

Replacement Series ◽

Amaranthus Hybridus ◽

Extractable P ◽

Common Purslane ◽

Smooth Pigweed ◽

Water Extractable

Replacement series studies were conducted under controlled conditions to determine the effect of phosphorus (P) rates and population densities on the competitiveness of smooth pigweed and common purslane with lettuce. Densities were 2, 4, and 8 plants per 113 cm2, whereas P rates were 0, 0.4, and 0.8 g PL−1soil. A P-deficient Histosol (0.3 mg water-extractable P L−1soil) was used. High P fertility enhanced the competitive ability of lettuce in smooth pigweed-lettuce mixtures. Smooth pigweed was not responsive to P rates. However, luxurious P consumption by smooth pigweed occurred, reducing the amount of the nutrient available for lettuce absorption. In common purslane-lettuce mixtures, the weed was responsive to P rates, increasing its competitive ability, whereas no increase in lettuce competitive ability was observed. Both weed species were more competitive than lettuce. Competition for P appears to be the main mechanism of common purslane interference on lettuce grown in low-P organic soils. Alternative fertilization strategies (i.e., banded applications) may reduce the effect of smooth pigweed on lettuce.

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Effect of Growth Stage and Water Stress on Barnyardgrass (Echinochloa crus-galli) Control and on Glyphosate Absorption and Translocation

Weed Science ◽

10.1017/s0043174500055284 ◽

1980 ◽

Vol 28 (3) ◽

pp. 277-282 ◽

Cited By ~ 60

Author(s):

M. S. Ahmadi ◽

L. C. Haderlie ◽

G. A. Wicks

Keyword(s):

Soil Moisture ◽

Water Stress ◽

Plant Height ◽

Growth Stage ◽

Field Capacity ◽

Stress Studies ◽

Herbicide Treatments ◽

Additional Reduction

Under greenhouse conditions, postemergence herbicide effectiveness was greater when barnyardgrass [Echinochloa crus-galli(L.) Beauv.] plants were 5-or 10-cm tall as compared to 15-or 20-cm tall. Absorption of14C-glyphosate [N-(phosphonomethyl)glycine] decreased from 58% of applied to 47% as plant height increased from 5 to 15 cm, and an additional reduction (to 32% of applied at 5 cm) occurred when terbutryn [2-(tert-butylamino)-4-(ethylamino)-6-(methylthio)-s-triazine] was added to glyphosate. Translocation of14C-glyphosate was reduced in older plants or when terbutryn was added to glyphosate. Water stress studies included soil moisture levels of 10, 20, 30, and 40% moisture (PW). Herbicide treatments were less effective at soil moisture levels below field capacity (30 PW). When soil moisture was 10 PW (-37 bar) absorption of14C-glyphosate was greatly reduced in plants treated at both 7.5-and 15-cm heights with or without terbutryn. At 10 PW only 15 to 20% of applied14C was absorbed whereas at 40 PW, absorption was over 45% and 62% with and without terbutryn, respectively. The addition of terbutryn to glyphosate resulted in decreased translocation for all soil moisture levels except the 20 PW treatment at the 15-cm height. Translocation of14C was greatly reduced for plants in soils at 10 PW for both herbicide treatments.

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Control of Yellow Nutsedge (Cyperus esculentus) and Smooth Pigweed (Amaranthus hybridus) in Summer Squash with Halosulfuron

Weed Technology ◽

10.1614/wt-08-016.1 ◽

2008 ◽

Vol 22 (4) ◽

pp. 660-665 ◽

Cited By ~ 5

Author(s):

Brian W. Trader ◽

Henry P. Wilson ◽

Thomas E. Hines

Keyword(s):

Field Study ◽

Field Experiments ◽

Cyperus Esculentus ◽

Weed Species ◽

Amaranthus Hybridus ◽

Yellow Nutsedge ◽

Application Method ◽

Summer Squash ◽

Smooth Pigweed

Field experiments were conducted in 1999, 2000, and 2001 to investigate PRE and POST applications of halosulfuron-methyl in combination with clomazone plus ethalfluralin for control of sedge and smooth pigweed in summer squash. Halosulfuron was applied PRE or POST to summer squash at 9, 18, or 27 g ai/ha in combination with a PRE application of clomazone at 175 g ai/ha plus ethalfluralin at 630 g ai/ha. Smooth pigweed control by addition of halosulfuron at 18 and 27 g/ha in combination with clomazone plus ethalfluralin PRE was greater than 89% independent of application method. Yellow nutsedge control was greater than 83% with POST applications of halosulfuron at 18 and 27 g/ha in combination with clomazone plus ethalfluralin PRE. Yellow nutsedge control was greater than 60% from all POST halosulfuron applications at 9, 18, or 27 g/ha in the greenhouse. In a separate field study without ethalfluralin PRE, rice flatsedge control was more than 85% from halosulfuron applied POST at 18 and 27 g/ha. Yellow summer squash and zucchini squash were injured as much as 52 and 47%, respectively, from inclusion of halosulfuron PRE or POST at 27 g/ha in treatments. Summer squash yields were generally not affected by halosulfuron rate, and were comparable to or higher than summer squash treated by only the mixture of clomazone plus ethalfluralin. In these studies, summer squash were injured by halosulfuron applied at 9 to 27 g/ha PRE or POST, yet rapidly recovered, making this herbicide acceptable for use in combination with clomazone and ethalfluralin for controlling several common weed species.

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683 PB 236 WATER STRESS REDUCES ASPARAGUS GROWTH

HortScience ◽

10.21273/hortsci.29.5.531d ◽

1994 ◽

Vol 29 (5) ◽

pp. 531d-531

Author(s):

Dan Drost

Keyword(s):

Soil Moisture ◽

Water Stress ◽

Root Zone ◽

Near Field ◽

Field Capacity ◽

Fresh Weight ◽

Irrigation Rate ◽

Growing Period ◽

Long Term Study ◽

Irrigation Treatments

In 1992, a long term study was initiated to determine water use of asparagus and to assess water stress effects on asparagus growth. Asparagus (Syn 4-56) crowns were planted and maintained at soil moisture levels near field capacity during the first year. In 1993, irrigation treatments based on 60, 40, and 0 percent of evapotranspiration (ET) were applied to asparagus during the fern growing period (mid-June to October). Soil moisture, shoot and root growth, and fern water potentials were measured throughout the year. Prior to the irrigation treatments, asparagus had 39 buds per plant with a shoot and root fresh weight of 573 and 270 grams, respectively. Soil moisture in the root zone (0 to 60 cm) approached the permanent wilting point in the 40%. and 0% of ET treatments by mid-August. A decrease in irrigation rate from 80 to 0% of ET had no effect on fern fresh weight at the end of the growing season. However, as irrigation rate decreased from 80 to 0% of ET, root fresh weight (586, 533, 415 grams) and bud number (78, 59, 53) decreased linearly. These results suggest yield and growth may be reduced in 1994.

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Predicting weed emergence for eight annual species in the northeastern United States

Weed Science ◽

10.1614/ws-04-025r ◽

2004 ◽

Vol 52 (6) ◽

pp. 913-919 ◽

Cited By ~ 65

Author(s):

Matthew W. Myers ◽

William S. Curran ◽

Mark J. VanGessel ◽

Dennis D. Calvin ◽

David A. Mortensen ◽

...

Keyword(s):

Model Verification ◽

Weed Species ◽

Common Ragweed ◽

Common Lambsquarters ◽

Eastern Black Nightshade ◽

Black Nightshade ◽

Giant Foxtail ◽

Smooth Pigweed ◽

Weed Emergence ◽

Large Crabgrass

A 2-yr experiment assessed the potential for using soil degree days (DD) to predict cumulative weed emergence. Emerged weeds, by species, were monitored every 2 wk in undisturbed plots. Soil DD were calculated at each location using a base temperature of 9 C. Weed emergence was fit with logistic regression for common ragweed, common lambsquarters, velvetleaf, giant foxtail, yellow foxtail, large crabgrass, smooth pigweed, and eastern black nightshade. Coefficients of determination for the logistic models fit to the field data ranged between 0.90 and 0.95 for the eight weed species. Common ragweed and common lambsquarters were among the earliest species to emerge, reaching 10% emergence before 150 DD. Velvetleaf, giant foxtail, and yellow foxtail were next, completing 10% emergence by 180 DD. The last weeds to emerge were large crabgrass, smooth pigweed, and eastern black nightshade, which emerged after 280 DD. The developed models were verified by predicting cumulative weed emergence in adjacent plots. The coefficients of determination for the model verification plots ranged from 0.66 to 0.99 and averaged 0.90 across all eight weed species. These results suggest that soil DD are good predictors for weed emergence. Forecasting weed emergence will help growers make better crop and weed management decisions.

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WATER DEFICIT ON GROWTH AND PHYSIOLOGICAL INDICATORS OF Bidens pilosa L. AND Bidens subalternans DC.

Revista Caatinga ◽

10.1590/1983-21252021v34n215rc ◽

2021 ◽

Vol 34 (2) ◽

pp. 388-397

Author(s):

MÁRCIO ALEXANDRE MOREIRA DE FREITAS ◽

HAMURÁBI ANIZIO LINS ◽

MATHEUS DE FREITAS SOUZA ◽

GABRIELLA DAIER OLIVEIRA PESSOA CARNEIRO ◽

VANDER MENDONÇA ◽

...

Keyword(s):

Water Stress ◽

Water Deficit ◽

Dry Matter ◽

Control Strategies ◽

Block Design ◽

Field Capacity ◽

Effective Control ◽

Weed Species ◽

Bidens Pilosa ◽

Physiological Indicators

ABSTRACT Stress caused by soil water deficit has been one of the main factors that inhibit plant growth. The knowledge of the factors related to the behavior of weed species under water stress conditions can contribute to the elaboration of effective control strategies. Two experiments were carried out to evaluate the effects of the degree and duration of water deficit on physiological and growth indicators of two weed species (Bidens pilosa L. and Bidens subalternans DC.). The stress degree was simulated by four soil moisture: 100, 75, 50, 25% of total soil capacity. The water deficit duration was evaluated by five intervals of water supply: 0, 1, 2, 3, 4, 5, and 6 days. The experiments were carried out in a randomized complete block design with six replicates. The evaluated variables were: the photosynthetic rate (A; μmol CO2 m-2), stomatal conductance (gs; μmol H2O m-2 s-1), transpiration (E; mmol H2O m-2 s-1), number of leaves per plant, and dry matter of the roots, stems, leaves, and total. The results showed that the species of B. pilosa and B. subalternans tolerate low water availability conditions. Low stomatal opening and loss of leaves are mechanisms that ensure the survival of Bidens plants to the water deficit. However, water stress close to 25% of field capacity caused the death of species. The B. subalternans had higher sensitivity to the water deficit, showing a lower dry matter of leaf, stem, and root than B. pilosa.

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Dynamics of the Potato Root (Solanum Spp.) Under Different Levels of Soil Moisture, in the Geographical Region of Riobamba, Ecuador

ESPOCH Congresses: The Ecuadorian Journal of S.T.E.A.M. ◽

10.18502/espoch.v1i1.9565 ◽

2021 ◽

Author(s):

R. Peña Murillo ◽

J. Velasteguí Cáceres ◽

J. León Ruiz

Keyword(s):

Soil Moisture ◽

Drip Irrigation ◽

Sandy Loam ◽

Maximum Yield ◽

Gravimetric Method ◽

Field Capacity ◽

Front Wall ◽

Root Dynamics ◽

Different Levels ◽

Solanum Spp

The root system of the potato (Solanum spp.) is often characterized as superficial and inefficient, with little capacity to extract water from the soil. Through a geographical study of the study area and root dynamics, the root behavior of the Victoria variety in Riobamba, Ecuador was evaluated, with the aim of assessing the applicability of “drip irrigation strategies with different levels of soil moisture” that allow the optimization of the water resource and the degree of tolerance of the crop to the lack of water through three treatments, 25%, 50% and 75%, between the levels of field capacity and permanent wilting point that are equivalent to 12.25% (T1), 10.5% (T2) and 8.75% (T3) of sandy loam soil moisture. Through front-wall rhizotrons the gravimetric method for recording soil moisture, and the Scheffé test, with a randomized block experimental design, were completed. The maximum root development was reached 110 days after the cultivation was established, with 77.5 cm (T3) at lower water availability. The maximum yield was reached at 132 days, with 34.72 t/ha (T1), followed by 32.11 t/ha (T2) with 126 days, and 28.45 t/ha (T3) with 121 days. Therefore, it is concluded that the maximum permissible humidity level for the variety is 10.5%, since lower levels would generate large losses. Keywords: rizotron, drip irrigation, soil moisture, geographical analysis. Resumen El sistema de raíces de la papa (Solanum spp.) a menudo se caracteriza por ser superficial e ineficiente, con poca capacidad para extraer agua del suelo. Mediante un estudio geográfico del área de estudio y la dinámica radicular se evalúa el comportamiento radicular de la variedad victoria en Riobamba-Ecuador, con el objetivo de valorar la aplicabilidad de estrategias de “riego por goteo con diferentes niveles de humedad en el suelo” que permitan la optimización del recurso hídrico y el grado de tolerancia del cultivo a la falta de agua mediante tres tratamientos 25%, 50% y 75% entre los niveles de capacidad de campo y punto de marchitez permanente que equivalen a 12,25%(T1), 10,5%(T2) y 8,75%(T3) de humedad del suelo franco arenoso. A través de rizotrones de pared frontal, el método gravimétrico para el registro de la humedad del suelo y la prueba de Scheffé, con un diseño experimental de bloques completos al azar. El máximo desarrollo radicular se alcanzó a los 110 días de establecido el cultivo con 77,5cm (T3) a una menor disponibilidad de agua. El rendimiento máximo se alcanzó a los 132 días con 34,72t/ha (T1), seguido de 32,11t/ha (T2) con 126 días y 28,45t/ha (T3) con 121 días. Por lo tanto, se concluye que el máximo nivel de humedad permisible para la variedad es 10,5%, ya que niveles inferiores generarían grandes pérdidas. Palabras claves: rizotrón, riego por goteo, humedad del suelo, análisis geográfico.

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Influence of selected environmental factors on glyphosate efficacy when applied to awnless barnyard grass (Echinochloa colona (L.) Link)

Australian Journal of Agricultural Research ◽

10.1071/a96141 ◽

1997 ◽

Vol 48 (5) ◽

pp. 695 ◽

Cited By ~ 24

Author(s):

Songyod Tanpipat ◽

Steve W. Adkins ◽

John T. Swarbrick ◽

Mark Boersma

Keyword(s):

Soil Moisture ◽

Water Stress ◽

Relative Humidity ◽

Environmental Factors ◽

Field Capacity ◽

Barnyard Grass ◽

Temperature Regimes ◽

Severe Water Stress ◽

Moisture Conditions

Glasshouse experiments were conducted to determine the effects of various environmental factors on glyphosate efficacy when applied to Echinochloa colona (L.) Link (awnless barnyard grass) plants. The variables examined were 4 soil moisture conditions (29, 42, 55, and 100% of field capacity), 2 levels of irradiance (400 and 800 µmol/m2· s), 3 temperature regimes (20/15, 30/25, and 35/30°C; day/night), and 2 levels of relative humidity (92 and 65%). The efficacy of 360 g acid equivalent glyphosate/ha was greatest when applied to well-watered (field capacity) plants that were placed under cool (20/25°C) and humid (92% relative humidity) conditions. The efficacy was least when applied to plants under severe water stress (29% of field capacity) that were placed under hot (35/30°C) and less humid (65% relative humidity) conditions. In all experiments, efficacy was not altered by the level of irradiance.

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Biochemical Alterations of Weeds in Response to Stress Caused by Herbicides and Total Plant Submersion

Planta Daninha ◽

10.1590/s0100-83582017350100085 ◽

2018 ◽

Vol 35 (0) ◽

Author(s):

M.G. MARCHEZAN ◽

L.A. AVILA ◽

C.E. SCHAEDLER ◽

L. AMARANTE ◽

A. SCHERNER ◽

...

Keyword(s):

Oxidative Stress ◽

Soil Moisture ◽

Field Capacity ◽

Cellular Damage ◽

Biological Efficiency ◽

Weed Species ◽

Biochemical Alterations ◽

Herbicide Treatments ◽

Randomized Experimental Design ◽

Response To Stress

ABSTRACT: The maximum biological efficiency of a herbicide is performed when the plants are in favorable condition to absorb and metabolize it. Stress situations, such as total submersion, cause stress in plants, reducing weed control efficiency and crop yield. The objective of this study was to verify whether different soil water content and herbicide treatments alter the components of the secondary metabolism and cause cellular damage in weed species Two experiments were conducted (I and II) in a completely randomized experimental design with a factorial scheme (2 x 2 x 4 and 2 x 5, respectively) and three replicates. The first experiment was conducted with two species (Leersia hexandra and Luziola peruviana), which were submitted to four herbicide treatments and soil moisture levels (field capacity and total submersion). Experiment II was performed with cockspur grass plants submitted to five herbicide treatments and the same soil moisture levels from experiment I. Leaf samples were collected for laboratory analyses seven days after establishing the soil moisture levels. Assessmentes were made for the levels of chlorophyll and carotenoids, activity of antioxidant enzymes, as well as levels of hydrogen peroxide and cellular damage. The results showed that all plant species studied showed higher oxidative stress under field capacity than under submersion. L.hexandra shows greater oxidative stress than L. peruviana regardless of the treatment applied: water regime or herbicide. Furthermore, the associations of glyphosate + clomazone and glyphosate + mixture of imazapyr + imazapic caused greater oxidative stress in L.hexandra and L.peruviana than glyphosate alone. All herbicides caused lipid peroxidation, reduced enzyme activity decreased concentrations of total chlorophyll, chlorophyll a and carotenoids on cockspur grass.

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