A Thermal Time Model to Predict Corn Poppy (Papaver rhoeas) Emergence in Cereal Fields

Weed Science ◽  
2009 ◽  
Vol 57 (6) ◽  
pp. 660-664 ◽  
Author(s):  
Jordi Izquierdo ◽  
José L. González-Andújar ◽  
Fernando Bastida ◽  
Juan A. Lezaún ◽  
María J. Sánchez del Arco
Keyword(s):  
Seedling Emergence ◽  
Gompertz Model ◽  
Sowing Date ◽  
Control Measures ◽  
Thermal Time ◽  
Base Temperature ◽  
Time Model ◽  
Data Set ◽  
Winter Cereals ◽  
Cereal Fields

Corn poppy is the most abundant broad-leaved weed in winter cereals of Mediterranean climate areas and causes important yield losses in wheat. Knowledge of the temporal pattern of emergence will contribute to optimize the timing of control measures, thus maximizing efficacy. The objectives of this research were to develop an emergence model on the basis of soil thermal time and validate it in several localities across Spain. To develop the model, monitoring of seedling emergence was performed weekly during the growing season in a cereal field located in northeastern Spain, during 3 yr. Cumulative thermal time from sowing date was used as the independent variable for predicting cumulative emergence. The Gompertz model was fitted to the data set of emergences. A base temperature of 1.0 C was estimated through iteration for maximum fit. The model accounted for 91% of the variation observed. Model validation in several localities and years showed general good performance in predicting corn poppy seedling emergence ( values ranging from 0.64 to 0.99 and root-mean-square error from 4.4 to 24.3). Ninety percent emergence was accurately predicted in most localities. Results showed that the model performs with greater reliability when significant rainfall (10 mm) occurs within 10 d after crop sowing. Complemented with in-field scouting, it may be a useful tool to better timing control measures in areas that are homogeneous enough regarding climate and crop management.

Modeling germination of smallflower umbrella sedge (Cyperus difformis L.) seeds from rice fields in California across suboptimal temperatures

2019 ◽  
Vol 33 (5) ◽  
pp. 733-738 ◽  
Author(s):  
Rafael M. Pedroso ◽  
Durval Dourado Neto ◽  
Ricardo Victoria Filho ◽  
Albert J. Fischer ◽  
Kassim Al-Khatib
Keyword(s):  
Growth Models ◽  
Rice Fields ◽  
Control Measures ◽  
Thermal Time ◽  
Model Parameters ◽  
Base Temperature ◽  
Probit Regression ◽  
Time Model ◽  
Thermal Requirements ◽  
Thermal Time Model

AbstractSmallflower umbrella sedge is a prolific C3 weed commonly found in rice fields in 47 countries. The increasing infestation of herbicide-resistant smallflower umbrella sedge populations threatens rice production. Our objectives for this study were to characterize thermal requirements for germination of smallflower umbrella sedge seeds from rice fields in California and to parameterize a population thermal-time model for smallflower umbrella sedge germination. Because the use of modeling techniques is hampered by the lack of thermal-time model parameters for smallflower umbrella sedge seed germination, trials were carried out by placing field-collected seeds in a thermogradient table set at constant temperatures of 11.7 to 41.7 C. Germination was assessed daily for 30 d, and the whole experiment was repeated a month later. Using probit regression analysis, thermal time to median germination [θT(50)], base temperature for germination (Tb), and SD of thermal times for germination [σθT(50)] were estimated from germination data, and model parameters were derived using the Solver tool in Microsoft Excel®. Germination rates increased linearly below the estimated optimum temperatures of 33.5 to 36 C. Estimated Tb averaged 16.7 C, whereas θT(50) equaled 17.1 degree-days and σθT(50) was only 0.1 degree-day. The estimated Tb for smallflower umbrella sedge is remarkably higher than that of japonica and indica types of rice, as well as Tb of important weeds in the Echinochloa complex. Relative to the latter, smallflower umbrella sedge has lower thermal-time requirements to germination and greater germination synchronicity. However, it would also initiate germination much later because of its higher Tb, given low soil temperatures early in the rice growing season in California. When integrated into weed growth models, these results might help optimize the timing and efficacy of smallflower umbrella sedge control measures.

Germination response of black nightshade (Solanum nigrum) to temperature and the establishment of a thermal time model

Weed Science ◽  
2021 ◽  
pp. 1-26
Author(s):  
Ziqing Ma ◽  
Hongjuan Huang ◽  
Zhaofeng Huang ◽  
Dongjing Guo ◽  
Muhammad Saeed ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seedling Emergence ◽  
Northern China ◽  
Solanum Nigrum ◽  
Thermal Time ◽  
Base Temperature ◽  
Time Model ◽  
Black Nightshade ◽  
Germination Response ◽  
Thermal Time Model

Abstract Black nightshade (Solanum nigrum L.) is one of the worst weeds in crop fields, and it spreads mainly by the dispersal of seeds. Temperature is one of the key environmental factors affecting seed germination. We investigated the seed germination response to temperature in six populations of S. nigrum from mid to northern China and derived mathematical models from germination data. The results showed that S. nigrum seeds exhibit distinct germination responses to temperature within the range of 15 to 35 °C. The optimum temperatures for the populations XJ1600, JL1697 and HLJ2134 were 30 °C, and those for the populations NMG1704, HN2160 and LN2209 were 25 °C, 20 °C and 15 °C, respectively. Based on the nonlinear fitting and thermal time models, the predicted base temperatures of the six populations ranged from 2.3 to 6.4 °C, and the required accumulated growing degree days (GDD) ranged from 50.3 to 106.0 °C·d. The base temperatures and the accumulated GDD for germination differed among populations, and there was a significant negative correlation. HLJ2134 population required a high base temperature and accumulated GDD for germination, indicating that it might highly adapted to a warmer and moister environment. Based on the different germination responses of S. nigrum populations to temperature, the thermal time model reflects an innate relationship between base temperature and accumulated GDD required for initiation of seed germination, which provides a better basis for predicting seedling emergence and the timing for optimal control of S. nigrum under field conditions.

Temperature and Water Potential as Parameters for Modeling Weed Emergence in Central-Northern Italy

Weed Science ◽  
2010 ◽  
Vol 58 (3) ◽  
pp. 216-222 ◽  
Author(s):  
Roberta Masin ◽  
Donato Loddo ◽  
Stefano Benvenuti ◽  
Maria Clara Zuin ◽  
Mario Macchia ◽  
...  
Keyword(s):  
Water Potential ◽  
Weed Control ◽  
Seedling Emergence ◽  
Thermal Time ◽  
Base Temperature ◽  
Hydrothermal Time ◽  
Data Set ◽  
Common Lambsquarters ◽  
Redroot Pigweed ◽  
Weed Emergence

Predicting weed emergence dynamics can help farmers to plan more effective weed control. The hydrothermal time concept has been used to model emergence as a function of temperature and water potential. Application of this concept is possible if the specific biological thresholds are known. This article provides a data set of base temperature and water potential of eight maize weeds (velvetleaf, redroot pigweed, common lambsquarters, large crabgrass, barnyardgrass, yellow foxtail, green foxtail, and johnsongrass). For five of these species, two ecotypes from two extreme regions of the predominant maize-growing area in Italy (Veneto and Tuscany), were collected and compared to check possible differences that may arise from using the same thresholds for different populations. Seedling emergence of velvetleaf and johnsongrass were modeled using three different approaches: (1) thermal time calculated assuming 5 C as base temperature for both species; (2) thermal time using the specific estimated base temperatures; and (3) hydrothermal time using the specific, estimated base temperatures and water potentials. All the species had base temperatures greater than 10 C, with the exception of velvetleaf (3.9 to 4.4 C) and common lambsquarters (2.0 to 2.6 C). All species showed a calculated base-water potential equal or up to −1.00 MPa. The thresholds of the two ecotypes were similar for all the studied species, with the exception of redroot pigweed, for which the Veneto ecotype showed a water potential lower than −0.41 MPa, whereas it was −0.62 MPa for the Tuscany ecotype. Similar thresholds have been found to be useful in hydrothermal time models covering two climatic regions where maize is grown in Italy. Furthermore, a comparison between the use of specific, estimated, and common thresholds for modeling weed emergence showed that, for a better determination of weed control timing, it is often necessary to estimate the specific thresholds.

scholarly journals Simulating maize phenology as a function of air temperature with a linear and a nonlinear model

2008 ◽  
Vol 43 (4) ◽  
pp. 449-455 ◽  
Author(s):  
Nereu Augusto Streck ◽  
Isabel Lago ◽  
Luana Fernandes Gabriel ◽  
Flavia Kaufmann Samboranha
Keyword(s):  
Nonlinear Model ◽  
Developmental Stages ◽  
Growing Season ◽  
Sowing Date ◽  
Thermal Time ◽  
Time Model ◽  
Data Set ◽  
Physiological Maturity ◽  
Maize Variety ◽  
Thermal Time Model

The objective of this study was to adapt a nonlinear model (Wang and Engel - WE) for simulating the phenology of maize (Zea mays L.), and to evaluate this model and a linear one (thermal time), in order to predict developmental stages of a field-grown maize variety. A field experiment, during 2005/2006 and 2006/2007 was conducted in Santa Maria, RS, Brazil, in two growing seasons, with seven sowing dates each. Dates of emergence, silking, and physiological maturity of the maize variety BRS Missões were recorded in six replications in each sowing date. Data collected in 2005/2006 growing season were used to estimate the coefficients of the two models, and data collected in the 2006/2007 growing season were used as independent data set for model evaluations. The nonlinear WE model accurately predicted the date of silking and physiological maturity, and had a lower root mean square error (RMSE) than the linear (thermal time) model. The overall RMSE for silking and physiological maturity was 2.7 and 4.8 days with WE model, and 5.6 and 8.3 days with thermal time model, respectively.

Plant development of triticale cv. Lasko at different sowing dates

1998 ◽  
Vol 130 (3) ◽  
pp. 297-306 ◽  
Author(s):  
R. E. L. NAYLOR ◽  
J. SU
Keyword(s):  
Stem Elongation ◽  
Seedling Emergence ◽  
Sowing Date ◽  
Thermal Time ◽  
Development Stages ◽  
Leaf Emergence ◽  
Sowing Dates ◽  
Time Requirements ◽  
Leaf Appearance ◽  
Double Ridge

The progress of leaf emergence, external morphology and apical development stages were recorded in sowings of triticale (cv. Lasko) made from February to November 1990 at Aberdeen (57° N). Leaf appearance and the number of primordia were related to thermal time (above a base of 0°C) except when photoperiods were <c. 11 h. The thermal time per phyllochron varied between leaves and the combined times for all the phyllochrons at a particular sowing accounted for the apparent response of average phyllochron to sowing date. The thermal time requirements for progression to the double ridge stage, terminal spikelet stage, onset of stem elongation and anthesis were similar except where photoperiods of <11 h occurred. The rate of grain primordium production was constant when photoperiod had been increasing at seedling emergence but the rate was reduced when the seedling experienced shortening photoperiods at emergence.

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 Application of the thermal time model for different Typha domingensis populations

2020 ◽  
Author(s):  
Fanny Mabel Carhuancho León ◽  
Pedro Luis Aguado Cortijo ◽  
María del Carmen Morató Izquierdo ◽  
María Teresa Castellanos Moncho
Keyword(s):  
Seed Germination ◽  
Mean Value ◽  
Thermal Time ◽  
Plant Responses ◽  
Base Temperature ◽  
Typha Domingensis ◽  
Time Model ◽  
Germination Response ◽  
Thermal Regimes ◽  
Thermal Time Model

Abstract Background: Cattail (Typha domingensis Pers.) is a perennial emergent plant which is used in Green Floating Filters (GFFs), one of the most innovative systems of wastewater treatment to bioremediate eutrophic waters and produce biomass as biofuel feedstocks. The establishment of cattails in GFFs depends on the seed germination and plant responses under conditions of a new habitat. This study analysed the germination responses of four different populations of cattails through a thermal time model to know their basic parameters of germination and which population would be more adapted to the conditions tested.Results: Seeds from the Badajoz (Ba), Cuenca (Cu), Madrid (Ma), Seville (Se) and Toledo (To) populations were exposed to different thermal regimes (constant, and alternating temperatures between 15 and 30°C) and different darkness treatments (between 0 and 20 days with 24h dark photoperiod, then exposed to light with 12h light/dark photoperiod) to determine the parameters of the thermal model from germination levels in each treatment. To population was used to validate the thermal time parameters of other populations. Regardless of the other parameters, no germination occurred in total darkness. The mean value of base temperature (Tb) was 16.4±0.2°C in all treatments. Optimum temperature (To) values in Ma and Ba were 25°C, and those in Cu and Se were 22.5°C. The germination response decreased when the temperature approached Tb and increased when it was close to To. In comparison to alternating temperatures, constant temperatures had the highest germination response and lowest thermal time (θT(50)). Darkness treatments had a direct relationship with θT(50). The population origin also affected seed germination; Cu had the highest values of To and germination response but had a lower θT(50), which coincides with the lowest mean ambient temperatures. Conclusion : According to these results, the germination response of cattails was high in all populations under optimal conditions but was affected to a greater or lesser extent depending on thermal regimes, darkness treatments, and populations. The thermal time model allowed us to determine that To was between 22.5-25ºC and that Cu is the best population regarding the germination response under the conditions tested.

Functional and quantitative analysis of seed thermal responses in prostrate knotweed (Polygonum aviculare) and common purslane (Portulaca oleracea)

Weed Science ◽  
1998 ◽  
Vol 46 (1) ◽  
pp. 83-90 ◽  
Author(s):  
B. C. Kruk ◽  
R. L. Benech-Arnold
Keyword(s):  
Quantitative Analysis ◽  
Seedling Emergence ◽  
Screening Method ◽  
Thermal Conditions ◽  
Thermal Time ◽  
Base Temperature ◽  
Emergence Period ◽  
Thermal Range ◽  
Polygonum Aviculare ◽  
Common Purslane

A screening method was used to characterize seed thermal responses of prostrate knotweed and common purslane, two important weeds invading wheat in the humid Pampa. Through this method, it was possible to detect thermal conditions that induce or break dormancy in both species. In addition, we were able to quantify changes in dormancy level in seed populations as a function of time of burial after dispersal, through changes in width of the thermal range within which germination can occur. Plotting the overlap of this thermal range and observed soil temperature throughout the year allowed the prediction of the seedling emergence period. This prediction was in agreement with observed seedling emergence in the field for both species, during 2 consecutive yr. From the analysis carried out under laboratory conditions, it was also possible to estimate required thermal time for germination of the nondormant fraction of the population and the base temperature above which thermal time is accumulated. The results obtained from this study are the basis for the formulation of seed germination models that predict not only the occurrence of seedling emergence in the field, but also the dynamics of germination within those periods.

A field study of the number of main shoot leaves in wheat in relation to vernalization and photoperiod

1992 ◽  
Vol 118 (3) ◽  
pp. 271-278 ◽  
Author(s):  
E. J. M. Kirby
Keyword(s):  
Field Experiments ◽  
Seedling Emergence ◽  
Wheat Plant ◽  
Sowing Date ◽  
Thermal Time ◽  
Model Function ◽  
Main Shoot ◽  
Leaf Emergence ◽  
Sowing Dates ◽  
Developmental Feature

SUMMARYThe number of leaves formed on the main shoot of a wheat plant is an important developmental feature, and a method of predicting this is essential for computer simulation of development.A model function was used to estimate vernalization from simulated sowing dates throughout a season. When expressed in terms of thermal time, it was estimated that a plant might be fully vernalized soon after seedling emergence or take up to about 1000 °Cd, depending on sowing date. When the simulated progress of vernalization was related to main shoot development (primordium initiation and leaf emergence) it was found that there were substantial differences between sowings in the rate of vernalization at comparable stages of apex development.A number of field experiments done in Britain from 1980 to 1984 with prominent commercial varieties, sown at various times from September to March, were analysed in terms of the thermal time to full vernalization and the photoperiod at the time of full vernalization, with vernalization simulated by the model function. In both winter and spring varieties, both of these variables significantly affected the number of main shoot leaves. Multiple linear regression using these two variables accounted for between 70 and 90% of the variance in leaf number, depending on variety.

Hydrothermal Emergence Model for Ripgut Brome (Bromus diandrus)

Weed Science ◽  
2013 ◽  
Vol 61 (1) ◽  
pp. 146-153 ◽  
Author(s):  
Addy L. García ◽  
Jordi Recasens ◽  
Frank Forcella ◽  
Joel Torra ◽  
Aritz Royo-Esnal
Keyword(s):  
Growth Function ◽  
Base Temperature ◽  
Independent Data ◽  
Data Set ◽  
Winter Cereal ◽  
Bromus Diandrus ◽  
Mediterranean Regions ◽  
Cereal Fields ◽  
Base Water Potential ◽  
The Relationship

A model that describes the emergence of ripgut brome was developed using a two-season data set from a no-tilled field in northeastern Spain. The relationship between cumulative emergence and hydrothermal time (HTT) was described by a sigmoid growth function (Chapman). HTT was calculated with a set of water potentials and temperatures, iteratively used, to determine the base water potential and base temperature. Emergence of ripgut brome was well described with a Chapman function. The newly-developed function was validated with four sets of data, two of them belonging to a third season in the same field and the other two coming from independent data from Southern Spain. The model also successfully described the emergence in different field management and tillage systems. This model may be useful for predicting ripgut brome emergence in winter cereal fields of semiarid Mediterranean regions.

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