scholarly journals Germination Parameters of Selected Summer Weeds: Transferring of the AlertInf Model to Other Geographical Regions

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 292
Author(s):  
Valentina Šoštarčić ◽  
Roberta Masin ◽  
Donato Loddo ◽  
Ema Brijačak ◽  
Maja Šćepanović
Keyword(s):  
Weed Management ◽  
Field Experiments ◽  
Chenopodium Album ◽  
Seedling Emergence ◽  
Amaranthus Retroflexus ◽  
Base Temperature ◽  
Time Model ◽  
Emergence Patterns ◽  
Geographical Regions ◽  
Base Water Potential

Effective weed management depends on correct control timing, which depends on seedling emergence dynamics. Since soil temperature and soil moisture are the two main factors that determine weed germination, the hydrothermal time model can be used to predict their emergence. The aim of this study was to estimate the base temperature (Tb) and base water potential (Ψb) for the germination of Chenopodium album, Amaranthus retroflexus, Setaria pumila, and Panicum capillare collected from fields in continental Croatia and then to compare these values with those of Italian populations embedded in the AlertInf model. Germination tests were performed at seven constant temperatures (ranging from 4 to 27 °C) and eight water potentials (0.00–1.00 MPa). The estimated Tb and Ψb were 3.4 °C and −1.38 MPa for C. album, 13.9 °C and −0.36 MPa for A. retroflexus, 6.6 °C and −0.71 MPa for S. pumila, and 11.0 °C and −0.87 MPa for P. capillare, respectively. According to the criterion of overlap of the 95% confidence intervals, only the Tb of C. album and the Ψb of A. retroflexus of the Croatian and Italian populations were similar. Further field experiments should be conducted to monitor the weed emergence patterns of C. album and calibrate the AlerInf equation parameters.

scholarly journals Biological Parameters for Germination of Selected Summer Weed Species: First Step to Transfer the Hydrothermal Model Alertinf to Croatia

2021 ◽  
Author(s):  
Valentina Šoštarčić ◽  
Roberta Masin ◽  
Donato Loddo ◽  
Ema Brijačak ◽  
Maja Šćepanović
Keyword(s):  
Weed Management ◽  
Field Experiments ◽  
Chenopodium Album ◽  
Seedling Emergence ◽  
Amaranthus Retroflexus ◽  
Base Temperature ◽  
Weed Species ◽  
Time Model ◽  
Emergence Patterns ◽  
Base Water Potential

The efficacy of weed management depends on the correct control timing according to the seedling emergence dynamics. Since soil temperature and soil moisture are two main factors that determine weed germination, the hydrothermal time model can be used to predict their emergence. The aim of this study was to estimate the base temperature (Tb) and base water potential (Ψb) for germination of Chenopodium album, Amaranthus retroflexus, Setaria pumila and Panicum capillare collected from fields in continental Croatia and then to compare these values with those of Italian populations embedded in the AlertInf model. Germination tests were performed at seven constant temperatures (ranging from 4 to 27°C) and eight water potentials (0.00 to - 1.00 MPa). Estimated Tb and Ψb were 3.4°C, -1.38 MPa for C. album, 13.9°C, -0.36 MPa for A. retroflexus, 6.6°C, -0.71 MPa for S. pumila and 11.0°C, -0.87 MPa for P. capillare, respectively. According to the criterion of overlap of the 95% confidence intervals, only Tb of C. album, and Ψb of A. retroflexus were similar between Croatian and Italian populations. Further field experiments should be conducted in the Croatian field to monitor weed emergence patterns of C. album and to calibrate the AlerInf equation parameters.

scholarly journals Effect of Crop Residues on Weed Emergence

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 163
Author(s):  
Nebojša Nikolić ◽  
Donato Loddo ◽  
Roberta Masin
Keyword(s):  
Weed Management ◽  
Crop Residues ◽  
Cropping Systems ◽  
Chenopodium Album ◽  
Seedling Emergence ◽  
Amaranthus Retroflexus ◽  
Weed Species ◽  
Field Quantity ◽  
Crop Fields ◽  
No Till

Weed behaviour in crop fields has been extensively studied; nevertheless, limited knowledge is available for particular cropping systems, such as no-till systems. Improving weed management under no-till conditions requires an understanding of the interaction between crop residues and the seedling emergence process. This study aimed to evaluate the influence of maize and wheat residues, applied in three different quantities (1, the field quantity, 0.5, and 1.5-fold amounts of the field quantity), on the emergence of eight weed species: Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, Digitaria sanguinalis, Echinochloa crus-galli, Setaria pumila, Sonchus oleraceus, and Sorghum halepense. The experiment was conducted over two consecutive years. The results showed that the quantities 1 and 1.5 could suppress seedling emergence by 20 and 44%, respectively, while the quantity 0.5 seems to promote emergence by 22% compared with the control without residues. Weed species showed different responses to crop residues, from C. album showing 56% less emergence to S. halepense showing a 44% higher emergence than the control without residues. Different meteorological conditions in the two-year experiment also exhibited a significant influence on weed species emergence.

scholarly journals Predicting Seedling Emergence of Three Canarygrass (Phalaris) Species under Semi-Arid Conditions Using Parametric and Non-Parametric Models

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 893
Author(s):  
Carlos Sousa-Ortega ◽  
Aritz Royo-Esnal ◽  
José María Urbano
Keyword(s):  
Field Experiments ◽  
Seedling Emergence ◽  
Parametric Models ◽  
Base Temperature ◽  
Weed Species ◽  
Emergence Period ◽  
Growing Seasons ◽  
Ceiling Temperature ◽  
Base Water Potential ◽  
Non Parametric

The Phalaris genus includes annual weed species such as short-spiked canarygrass (Phalaris brachystachys Link.), little-seed canarygrass (Phalaris minor Retz.) and hood canarygrass (Phalaris paradoxa L.), which are especially problematic in Spain; as such, there is a need to develop models to predict the timing of their emergence. Field experiments were conducted at two different locations during two (2006/07 and 2007/08) and three (from 2005/06 to 2007/08) growing seasons. In both locations, 500 seeds of each Phalaris species were sown each growing season, simulating rain-fed cereal field conditions. In addition, the models were validated with three, four and eight independent experiments for P. brachystachys, P. minor and P. paradoxa, respectively. The emergence period of the three Phalaris species lasted between 31 and 48 days after sowing (DAS), showing two main flushes. The three cardinal points for parametric and non-parametric models were established to be between −1 °C and 1 °C for base temperature, between 9.8 °C and 11.8 °C for optimal temperature and between 21.2 °C and 23.4 °C for ceiling temperature; base water potential was estimated to be between −1 and −1.1 MPa. Both parametric and non-parametric models obtained similar results and were successfully validated in 12 out of 15 independent experiments.

Characterization and Modeling of Itchgrass (Rottboellia cochinchinensis) Biphasic Seedling Emergence Patterns in the Tropics

Weed Science ◽  
2015 ◽  
Vol 63 (3) ◽  
pp. 623-630 ◽  
Author(s):  
Ramon G. Leon ◽  
Jordi Izquierdo ◽  
José Luis González-Andújar∗
Keyword(s):  
Field Experiments ◽  
Seedling Emergence ◽  
Thermal Time ◽  
Second Phase ◽  
Growing Degree Days ◽  
Degree Days ◽  
Weed Species ◽  
Time Model ◽  
Emergence Patterns ◽  
Emergence Phase

Itchgrass is an aggressive weed species in tropical agroecosystems. Because of phytosanitary restrictions to exports, pineapple producers must use a zero tolerance level for this species. An understanding of itchgrass seedling emergence would help producers to better time POST control. The objective of the present study was to characterize itchgrass seedling emergence patterns and develop a predictive model. Multiple field experiments were conducted in four agricultural fields in Costa Rica between 2010 and 2011 for a total of 9 site-years. Itchgrass consistently showed a biphasic emergence pattern, with a first emergence phase that was faster and more consistent across site-years than the second one. Weibull + logistic models based on chronological time (R2adj= 0.92) and thermal time withTbase= 20 C (R2adj= 0.92) provided the best fit for the combined emergence data for two experimental locations in 2010. Both models predicted itchgrass seedling emergence adequately for most site-years, but the thermal-time model was more accurate (R2adj= 0.64 to 0.86) than the chronological model (R2adj= 0.31 to 0.74), especially when temperatures were high. Both models showed high accuracy in the first emergence phase but tended to underestimate emergence rate during the second phase. The models predicted 50% emergence at 14 d or 80 growing degree days and the stabilization of the first emergence phase at approximately 25 d or 200 growing degree days. Thus, these models can be used to properly time itchgrass POST control. More research is needed to understand the regulatory mechanisms responsible for the variability of the second emergence phase.

scholarly journals Irrigation Timing as a Practice of Effective Weed Management in Established Alfalfa (Medicago sativa L.) Crop

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 550
Author(s):  
Panagiotis Kanatas ◽  
Ioannis Gazoulis ◽  
Ilias Travlos
Keyword(s):  
Medicago Sativa ◽  
Weed Management ◽  
Cultural Practices ◽  
Block Design ◽  
Chenopodium Album ◽  
Stand Density ◽  
Climatic Conditions ◽  
Amaranthus Retroflexus ◽  
Forage Yield ◽  
Medicago Sativa L

Irrigation is an agronomic practice of major importance in alfalfa (Medicago sativa L), especially in the semiarid environments of Southern Europe. Field experimentation was conducted in Western Greece (2016–2018) to evaluate the effects of irrigation timing on weed presence, alfalfa yield performance, and forage quality. In a randomized complete block design (four replications), two cultivars (“Ypati 84” and “Hyliki”) were the main plots, while three irrigation timings were the subplots (split-plot). The irrigation timings were IT-1, IT-2, and IT-3, denoting irrigation 1 week before harvest, 1 week after harvest, and 2 weeks after harvest, respectively. IT-1 reduced Solanum nigrum L. density by 54% and 79% as compared to IT-3 and IT-2, respectively. Chenopodium album L. density was the highest under IT-2. IT-3 resulted in 41% lower Amaranthus retroflexus L. density in comparison to IT-2, while the lowest values were observed under IT-1. Stand density and stems·plant−1 varied between years (p ≤ 0.05). Mass·stem−1 and alfalfa forage yield were affected by the irrigation timings (p ≤ 0.001). Total weed density and forage yield were negatively correlated in both the second (R2 = 87.013%) and the fourth (R2 = 82.691%) harvests. IT-1 and IT-3 increased forage yield, leaf per stem ratio, and crude protein as compared to IT-2. Further research is required to utilize the use of cultural practices for weed management in perennial forages under different soil and climatic conditions.

Modeling germination and seedling elongation of common lambsquarters (Chenopodium album)

Weed Science ◽  
1999 ◽  
Vol 47 (2) ◽  
pp. 149-155 ◽  
Author(s):  
Erivelton S. Roman ◽  
A. Gordon Thomas ◽  
Stephen D. Murphy ◽  
Clarence J. Swanton
Keyword(s):  
Seed Germination ◽  
Water Potential ◽  
Mechanistic Model ◽  
Chenopodium Album ◽  
Seedling Emergence ◽  
Probit Analysis ◽  
Hydrothermal Time ◽  
Time Model ◽  
Common Lambsquarters ◽  
Radicle Elongation

The ability to predict time of weed seedling emergence relative to the crop is an important component of a mechanistic model describing weed and crop competition. In this paper, we hypothesized that the process of germination could be described by the interaction of temperature and water potential and that the rate of seedling shoot and radicle elongation vary as a function of temperature. To test these hypotheses, incubator studies were conducted using seeds and seedlings of common lambsquarters. Probit analysis was used to account for variation in cardinal temperatures and base water potentials and to develop parameters for a new mathematical model that describes seed germination and shoot and radicle elongation in terms of hydrothermal time and temperature, respectively. This hydrothermal time model describes the phenology of seed germination using a single curve, generated from the relationship of temperature and water potential.

scholarly journals A hydrothermal after-ripening time model for seed dormancy loss in Bromus tectorum L.

2006 ◽  
Vol 16 (1) ◽  
pp. 17-28 ◽  
Author(s):  
Necia B. Bair ◽  
Susan E. Meyer ◽  
Phil S. Allen
Keyword(s):  
Water Potential ◽  
Time Course ◽  
Bromus Tectorum ◽  
Base Temperature ◽  
Time Model ◽  
Seed Collection ◽  
Ripening Time ◽  
Water Potentials ◽  
Ripening Rate ◽  
Base Water Potential

After-ripening, the loss of dormancy under dry conditions, is associated with a decrease in mean base water potential for germination ofBromus tectorumL. seeds. After-ripening rate is a linear function of temperature above a base temperature, so that dormancy loss can be quantified using a thermal after-ripening time (TAR) model. To incorporate storage water potential into TAR, we created a hydrothermal after-ripening time (HTAR) model. Seeds from twoB. tectorumpopulations were stored under controlled temperatures (20 or 30 °C) and water potentials (−400 to −40 MPa). Subsamples were periodically removed from each storage treatment and incubated at 15 or 25 °C to determine germination time courses. Dormancy status (mean base water potential) was calculated from each time course using hydrothermal time equations developed for each seed collection. Seeds stored at −400 MPa did not after-ripen. At water potentials from −400 to −150 MPa, the rate of after-ripening increased approximately linearly with increasing water potential. Between −150 and −80 MPa, there was no further increase in after-ripening rate, while at −40 MPa seeds did not after-ripen and showed loss of vigour. These results suggest that the concept of critical water potential thresholds, previously shown to be associated with metabolic activity and desiccation damage in partially hydrated seeds, is also relevant to the process of after-ripening. The HTAR model generally improved field predictions of dormancy loss when the soil was very dry. Reduced after-ripening rate under such conditions provides an ecologically relevant explanation of how seeds prolong dormancy at high summer soil temperatures.

Seed and Germination Biology ofDittrichia graveolens(Stinkwort)

2013 ◽  
Vol 6 (3) ◽  
pp. 371-380 ◽  
Author(s):  
Rachel N. Brownsey ◽  
Guy B. Kyser ◽  
Joseph M. DiTomaso
Keyword(s):  
Seed Germination ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Seed Viability ◽  
Base Temperature ◽  
Time Model ◽  
Wide Range ◽  
Total Seed ◽  
Thermal Time Model ◽  
Seed Characteristics

AbstractUnderstanding seed characteristics and seedling establishment patterns is essential for the development of effective management strategies for invasive annual species.Dittrichia graveolens(stinkwort) has increased its range rapidly within California since 1995, yet its biology is not well understood, which has led to poorly timed management. In this study, seed viability, germination, longevity, and dormancy, as well as seedling emergence characteristics ofD. graveolenswere evaluated in field, greenhouse, and laboratory experiments in Davis, CA, over a 2-yr period (fall 2010 to summer 2012). In the laboratory, seed germination ofD. graveolensoccurred at a wide range of constant temperatures (12 to 34 C). Cumulative germination was comparable to total seed viability (80 to 95%) at optimal germination temperatures, indicating that primary (innate) dormancy is likely absent. The base temperature for germination was identified using a thermal time model: 6.5 C and 4 C for 2010 and 2011 seed populations, respectively. In the field, seedlings emerged from fall through spring following precipitation events. A very low percentage of seedlings (2.5%) emerged in the second year after planting. Equivalent seedling emergence was observed over a wide range of light conditions (100, 50, 27, and 9% of available sunlight) in a greenhouse experiment, indicating that seed germination is not limited by high or low light. Results from these seed experiments improve our understanding of the reproductive biology of this rapidly expanding exotic annual and provide valuable information for developing effective timing and longevity of management programs.

scholarly journals Weed Management in Transplanted Bell Pepper (Capsicum annuum) with Pretransplant Tank Mixes of Sulfentrazone, S-metolachlor, and Dimethenamid-p

HortScience ◽  
2008 ◽  
Vol 43 (5) ◽  
pp. 1492-1494 ◽  
Author(s):  
Darren E. Robinson ◽  
Kristen McNaughton ◽  
Nader Soltani
Keyword(s):  
Weed Management ◽  
Chenopodium Album ◽  
Fruit Size ◽  
Field Trials ◽  
Amaranthus Retroflexus ◽  
Ambrosia Artemisiifolia ◽  
Bell Pepper ◽  
Weed Species ◽  
Marketable Yield ◽  
Excellent Control

Pepper growers currently have limited access to many effective broadleaf herbicides. Field trials were conducted over a 3-year period in Ontario to study the effect of tank mixtures of sulfentrazone (100 or 200 g·ha−1 a.i.) with either s-metolachlor (1200 or 2400 g·ha−1 a.i.) or dimethenamid-p (750 or 1500 g·ha−1 a.i.) on transplanted bell pepper. Under weed-free conditions, there was no visual injury or reduction in plant height, fruit number, fruit size, or marketable yield of transplanted pepper with pretransplant applications of sulfentrazone applied in tank mixtures with s-metolachlor or dimethenamid-p. The tank mixture of sulfentrazone + s-metolachlor gave greater than 85% control of redroot pigweed (Amaranthus retroflexus) and eastern black nightshade (Solanum ptycanthum), but only 70% to 76% control of velvetleaf (Abutilon theophrasti), common ragweed (Ambrosia artemisiifolia), and common lambsquarters (Chenopodium album). The combination of sulfentrazone + dimethenamid-p provided good to excellent control of all weed species except velvetleaf. Based on this study, sulfentrazone and dimethenamid-p have potential for minor use registration in pepper.

scholarly journals Adjuvants to Improve Phenmedipham + Desmedipham + Ethofumesate Efficacy Against Weeds in Sugar Beet (Beta vulgaris)

2019 ◽  
Vol 37 ◽  
Author(s):  
E. IZADI-DARBANDI ◽  
A. ALIVERDI ◽  
M. ANABESTANI ◽  
A. SHAMSABADI
Keyword(s):  
Sugar Beet ◽  
Weed Management ◽  
Chenopodium Album ◽  
Amaranthus Retroflexus ◽  
Tribulus Terrestris ◽  
Weed Density ◽  
Beet Root ◽  
Significant Difference ◽  
Sugar Beet Root ◽  
Density And Biomass

ABSTRACT: The efficacy of reduced (411.5 and 617.2 a.i. ha-1) and recommended (823.0 g a.i. ha-1) rates of phenmedipham + desmedipham + ethofumesate on the control of Amaranthus retroflexus, Amaranthus blitoides, Chenopodium album, and Tribulus terrestris in sugar beet field was investigated when they were tank-mixed with and without Adigor (0.5% v/v), Ammonium sulphate (2% v/v), Citogate (0.2% v/v), D-Octil (0.3% v/v), Hydro-Max (0.5% v/v), and Volck (0.5% v/v). When the herbicide was applied alone, there was no significant difference between the rates of 617.2 and 823.0 g a.i. ha-1 for reduction of total weed density and biomass. Significantly, the adjuvants decreased total weed density and biomass. However, there was no significant difference among the performance of adjuvants. The sugar beet root and sucrose yields were increased significantly by increasing herbicide rate as a result of an improvement in weed control. Although herbicide efficacy was influenced in a similar manner by all the adjuvants, the best results were found as follows: root yield was increased up to 9.66% (71.31 Mg ha-1) by applying the recommended rate of phenmedipham + desmedipham + ethofumesate plus Adigor compared to weed-free check (64.68 Mg ha-1) whereas sucrose yield was increased up to 26.48% (13.21 t ha-1) by applying the recommended rate of phenmedipham + desmedipham + ethofumesate plus HydroMax compared to weed-free check (10.45 t ha-1). From an economic and ecological standpoint, these two adjuvants can be suggested to optimize the recommended rate of phenmedipham + desmedipham + ethofumesate in weed management.

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