Modeling site-specific wild oat (Avena fatua) emergence across a variable landscape

Weed Science ◽  
2006 ◽  
Vol 54 (5) ◽  
pp. 838-846 ◽  
Author(s):  
Eric R. Page ◽  
Robert S. Gallagher ◽  
Armen R. Kemanian ◽  
Hao Zhang ◽  
E. Patrick Fuerst
Keyword(s):  
Water Potential ◽  
Crop Residue ◽  
Seedling Emergence ◽  
Bare Soil ◽  
Slope Aspect ◽  
Weibull Function ◽  
Wild Oat ◽  
Site Specific ◽  
Wheat Field ◽  
The Impact

The spatial and temporal pattern of wild oat emergence in eastern Washington is affected by the steep, rolling hills that dominate this landscape. The objective of this study was to assess the impact of landscape position and crop residue on the emergence phenology of wild oat. Emergence of a natural wild oat infestation was characterized over two growing seasons (2003 and 2004), at two wheat residue levels (0 and 500 g m−2), and at five landscape positions differing in slope, aspect, and elevation in a no-till winter wheat field. Wild oat emerged 1 to 2 wk earlier at south-facing landscape positions than at north-facing landscape positions. Crop residue delayed wild oat emergence by 7 to 13 d relative to bare soil at south-facing positions in 2003 and had a reduced effect on emergence at north-facing landscape positions. Therefore, preserving surface residues tended to synchronize emergence across the landscape and may facilitate better timing of weed control where residue is present. Emergence of wild oat was modeled as a function of thermal time adjusted by water potential using a Weibull function. Temperature explained more variation in the model than water potential. This model explained much of the variability in wild oat emergence among landscape positions over these 2 yr and may be useful as a tool to predict the timing of wild oat emergence. Results also indicate that site-specific modeling is a plausible approach to improving prediction of weed seedling emergence.

An Emergence Model for Wild Oat (Avena fatua)

Weed Science ◽  
2007 ◽  
Vol 55 (6) ◽  
pp. 584-591 ◽  
Author(s):  
Krishona Martinson ◽  
Beverly Durgan ◽  
Frank Forcella ◽  
Jochum Wiersma ◽  
Kurt Spokas ◽  
...  
Keyword(s):  
Seedling Emergence ◽  
Soil Water Potential ◽  
The United States ◽  
Weibull Function ◽  
Wild Oat ◽  
Degree Days ◽  
Weekly Basis ◽  
Emergence Patterns ◽  
Base Soil ◽  
Permanent Quadrats

Wild oat is an economically important annual weed throughout small grain producing regions of the United States and Canada. Timely and more accurate control of wild oat may be developed if there is a better understanding of its emergence patterns. The objectives of this research were to evaluate the emergence pattern of wild oat and determine if emergence could be predicted using soil growing degree days (GDD) and/or hydrothermal time (HTT). Research plots were established at Crookston, MN, and Fargo, ND, in 2002 and 2003. On a weekly basis, naturally emerging seedlings were counted and removed from six 0.37-m2permanent quadrats randomly distributed in a wild oat–infested area. This process was repeated until no additional emergence was observed. Wild oat emergence began between May 1 and May 15 at both locations and in both years and continued for 4 to 6 wk. Base soil temperature and soil water potential associated with wild oat emergence were determined to be 1 C and −0.6 MPa, respectively. Seedling emergence was correlated with GDD and HTT but not calendar days (P = 0.15). A Weibull function was fitted to cumulative wild oat emergence and GDD and HTT. The models for GDD (n= 22,r2= 0.93, root mean square error [RMSE] = 10.7) and HTT (n= 22,r2= 0.92, RMSE = 11.2) closely fit observed emergence patterns. The latter model is the first to use HTT to predict wild oat emergence under field conditions. Both models can aid in the future study of wild oat emergence and assist growers and agricultural professionals with planning timely and more accurate wild oat control.

scholarly journals The impact of seed burial depths and post-emergence herbicides on seedling emergence and biomass production of wild oat (Avena fatua L.): Implications for management

PLoS ONE ◽  
2020 ◽  
Vol 15 (10) ◽  
pp. e0240944
Author(s):  
Muhammad Mudassar Maqbool ◽  
Shazia Naz ◽  
Tasneem Ahmad ◽  
Muhammad Shahid Nisar ◽  
Hassan Mehmood ◽  
...  
Keyword(s):  
Biomass Production ◽  
Seedling Emergence ◽  
Avena Fatua ◽  
Wild Oat ◽  
Seed Burial ◽  
The Impact

A Model for Predicting Common Cocklebur (Xanthium strumarium) Emergence in Soybean

Weed Science ◽  
2007 ◽  
Vol 55 (4) ◽  
pp. 341-345 ◽  
Author(s):  
Jason K. Norsworthy ◽  
Marcos J. Oliveira
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Soil Depth ◽  
Seedling Emergence ◽  
Soil Water Potential ◽  
Thermal Fluctuation ◽  
Parameter Estimates ◽  
Weibull Function ◽  
Base Temperature ◽  
Presence And Absence

The objective of this research was to develop a model to predict common cocklebur seedling emergence in spring tillage and no-spring-tillage systems in the presence and absence of a soybean canopy. A Weibull function was used to accumulate heat units (i.e., growing degree days) at a 2.5 cm soil depth on days when mean soil temperature, soil water potential, and soil thermal fluctuation were above established thresholds. The base temperature, soil water potential, and soil thermal fluctuation thresholds used for model development were 17 C, −100 kPa, and 7.5 C, respectively. A single function adequately described common cocklebur seedling emergence in the presence and absence of drill-seeded soybean from data combined over an artificial (2004) and natural seedbank (2005) (R2= 0.986). Model parameterization differed between the artificial and natural seedbank in the absence of spring tillage, but emergence was adequately described, regardless of soybean presence. Separate parameter estimates for the artificial and natural seedbanks were needed to adequately describe emergence in the system without spring tillage (R2= 0.975 to 0.984). The ability of the model to account for reduced emergence when soil moisture is limited or when daily thermal fluctuation requirements are not met could assist practitioners with assessments associated with field scouting for weeds as well as other management decisions.

The Impact of Bioconjugation on the Interfacial Activity of a Protein Biosurfactant

2018 ◽  
Author(s):  
Hossam H Tayeb ◽  
Marina Stienecker ◽  
Anton Middelberg ◽  
Frank Sainsbury
Keyword(s):  
Polyethylene Glycol ◽  
Colloidal Stability ◽  
Point Mutations ◽  
Pharmaceutical Formulations ◽  
Industrial Processes ◽  
Parent Molecule ◽  
Site Specific ◽  
Interfacial Activity ◽  
Surface Active ◽  
The Impact

Biosurfactants, are surface active molecules that can be produced by renewable, industrially scalable biologic processes. DAMP4, a designer biosurfactant, enables the modification of interfaces via genetic or chemical fusion to functional moieties. However, bioconjugation of addressable amines introduces heterogeneity that limits the precision of functionalization as well as the resolution of interfacial characterization. Here we designed DAMP4 variants with cysteine point mutations to allow for site-specific bioconjugation. The DAMP4 variants were shown to retain the structural stability and interfacial activity characteristic of the parent molecule, while permitting efficient and specific conjugation of polyethylene glycol (PEG). PEGylation results in a considerable reduction on the interfacial activity of both single and double mutants. Comparison of conjugates with one or two conjugation sites shows that both the number of conjugates as well as the mass of conjugated material impacts the interfacial activity of DAMP4. As a result, the ability of DAMP4 variants with multiple PEG conjugates to impart colloidal stability on peptide-stabilized emulsions is reduced. We suggest that this is due to constraints on the structure of amphiphilic helices at the interface. Specific and efficient bioconjugation permits the exploration and investigation of the interfacial properties of designer protein biosurfactants with molecular precision. Our findings should therefore inform the design and modification of biosurfactants for their increasing use in industrial processes, and nutritional and pharmaceutical formulations.

scholarly journals Site-specific N-glycosylation analysis of animal cell culture-derived Zika virus proteins

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexander Pralow ◽  
Alexander Nikolay ◽  
Arnaud Leon ◽  
Yvonne Genzel ◽  
Erdmann Rapp ◽  
...  
Keyword(s):  
Zika Virus ◽  
Animal Cell ◽  
Gradient Centrifugation ◽  
Viral Envelope ◽  
Protein Glycosylation ◽  
High Yield ◽  
Structural Protein ◽  
Site Specific ◽  
E Protein ◽  
The Impact

AbstractHere, we present for the first time, a site-specific N-glycosylation analysis of proteins from a Brazilian Zika virus (ZIKV) strain. The virus was propagated with high yield in an embryo-derived stem cell line (EB66, Valneva SE), and concentrated by g-force step-gradient centrifugation. Subsequently, the sample was proteolytically digested with different enzymes, measured via a LC–MS/MS-based workflow, and analyzed in a semi-automated way using the in-house developed glyXtoolMS software. The viral non-structural protein 1 (NS1) was glycosylated exclusively with high-mannose structures on both potential N-glycosylation sites. In case of the viral envelope (E) protein, no specific N-glycans could be identified with this method. Nevertheless, N-glycosylation could be proved by enzymatic de-N-glycosylation with PNGase F, resulting in a strong MS-signal of the former glycopeptide with deamidated asparagine at the potential N-glycosylation site N444. This confirmed that this site of the ZIKV E protein is highly N-glycosylated but with very high micro-heterogeneity. Our study clearly demonstrates the progress made towards site-specific N-glycosylation analysis of viral proteins, i.e. for Brazilian ZIKV. It allows to better characterize viral isolates, and to monitor glycosylation of major antigens. The method established can be applied for detailed studies regarding the impact of protein glycosylation on antigenicity and human pathogenicity of many viruses including influenza virus, HIV and corona virus.

Influence of chaff and chaff lines on weed seed survival and seedling emergence in Australian cropping systems

2020 ◽  
pp. 1-22
Author(s):  
Michael J. Walsh ◽  
Annie E. Rayner ◽  
Annie Rutledge ◽  
John C. Broster
Keyword(s):  
Cropping Systems ◽  
Seedling Emergence ◽  
Field Studies ◽  
Wild Oat ◽  
Weed Seed ◽  
Weed Species ◽  
Environment Effect ◽  
Seed Survival ◽  
Cropping Seasons ◽  
Rigid Ryegrass

Abstract Chaff lining and chaff tramlining are harvest weed seed control (HWSC) systems that involve the concentration of weed seed containing chaff material into narrow (20 to 30 cm) rows between or on the harvester wheel tracks during harvest. These lines of chaff are left intact in the fields through subsequent cropping seasons in the assumption that the chaff environment is unfavourable for weed seed survival. The chaff row environment effect on weed seed survival was examined in field studies, while chaff response studies determined the influence of increasing amounts of chaff on weed seedling emergence. The objectives of these studies were to determine 1) the influence of chaff lines on the summer-autumn seed survival of selected weed species; and 2) the influence of chaff type and amount on rigid ryegrass seedling emergence. There was frequently no difference (P>0.05) in survival of seed of four weed species (rigid ryegrass, wild oat, annual sowthistle and turnip weed) when these seed were placed beneath or beside chaff lines. There was one instance where wild oat seed survival was increased (P<0.05) when seed were placed beneath compared to beside a chaff line. The pot studies determined that increasing amounts of chaff consistently resulted in decreasing numbers of rigid ryegrass seedlings emerging through chaff material. The suppression of emergence broadly followed a linear relationship where there was approximately a 2.0% reduction in emergence with every 1.0 t ha-1 increase in chaff material. This relationship was consistent across wheat, barley, canola and lupin chaff types, indicating that the physical presence of the chaff was more important than chaff type. These studies indicated that chaff lines may not affect the over summer-autumn survival of the contained weed seeds but the subsequent emergence of weed seedlings will be restricted by high amounts of chaff (>40 t ha-1).

scholarly journals Impact of crop residue management on crop production and soil chemistry after seven years of crop rotation in temperate climate, loamy soils

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4836 ◽  
Author(s):  
Marie-Pierre Hiel ◽  
Sophie Barbieux ◽  
Jérôme Pierreux ◽  
Claire Olivier ◽  
Guillaume Lobet ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Crop Production ◽  
Crop Residue ◽  
Crop Residues ◽  
Conventional Tillage ◽  
Residue Management ◽  
Temperate Climate ◽  
Reduced Tillage ◽  
Crop Residue Management ◽  
The Impact

Society is increasingly demanding a more sustainable management of agro-ecosystems in a context of climate change and an ever growing global population. The fate of crop residues is one of the important management aspects under debate, since it represents an unneglectable quantity of organic matter which can be kept in or removed from the agro-ecosystem. The topic of residue management is not new, but the need for global conclusion on the impact of crop residue management on the agro-ecosystem linked to local pedo-climatic conditions has become apparent with an increasing amount of studies showing a diversity of conclusions. This study specifically focusses on temperate climate and loamy soil using a seven-year data set. Between 2008 and 2016, we compared four contrasting residue management strategies differing in the amount of crop residues returned to the soil (incorporation vs. exportation of residues) and in the type of tillage (reduced tillage (10 cm depth) vs. conventional tillage (ploughing at 25 cm depth)) in a field experiment. We assessed the impact of the crop residue management on crop production (three crops—winter wheat, faba bean and maize—cultivated over six cropping seasons), soil organic carbon content, nitrate (${\mathrm{NO}}_{3}^{-}$), phosphorus (P) and potassium (K) soil content and uptake by the crops. The main differences came primarily from the tillage practice and less from the restitution or removal of residues. All years and crops combined, conventional tillage resulted in a yield advantage of 3.4% as compared to reduced tillage, which can be partly explained by a lower germination rate observed under reduced tillage, especially during drier years. On average, only small differences were observed for total organic carbon (TOC) content of the soil, but reduced tillage resulted in a very clear stratification of TOC and also of P and K content as compared to conventional tillage. We observed no effect of residue management on the ${\mathrm{NO}}_{3}^{-}$ content, since the effect of fertilization dominated the effect of residue management. To confirm the results and enhance early tendencies, we believe that the experiment should be followed up in the future to observe whether more consistent changes in the whole agro-ecosystem functioning are present on the long term when managing residues with contrasted strategies.

CONTROLLING SUFETULA SPP.: A COCONUT INSECT PEST ON PEAT SOILS

2007 ◽  
Vol 43 (3) ◽  
pp. 289-299 ◽  
Author(s):  
X. BONNEAU ◽  
M. HUSNI ◽  
L. BEAUDOIN-OLLIVIER ◽  
JOKO SUSILO
Keyword(s):  
Insect Pest ◽  
Bare Soil ◽  
Cultural Control ◽  
Control Measures ◽  
Control Methods ◽  
Peat Soils ◽  
Depressive Effect ◽  
Moss Cover ◽  
Adult Insect ◽  
The Impact

We demonstrated experimentally that Sufetula, a root-mining insect, has a depressive effect on coconut yields on peat soils. The impact of the pest resulted in a shortfall in earnings that warranted taking control measures. We considered control methods suitable for rehabilitating infested mature coconut plantings and for preserving young coconut plantings. Currently, cultural control is the only effective method. It involves eliminating all identified shelters for the adult insect, i.e. fern cover and heaps of coconut waste (dry fronds and husks). The aim is to achieve totally bare soil, with moss cover that does not attract the pest, or planted with an unattractive intercrop such as pineapple.

Genetic Diversity of Wild Oat (Avena fatua)Populations from China and the United States

Weed Science ◽  
2007 ◽  
Vol 55 (2) ◽  
pp. 95-101 ◽  
Author(s):  
Runzhi Li ◽  
Shiwen Wang ◽  
Liusheng Duan ◽  
Zhaohu Li ◽  
Michael J. Christoffers ◽  
...  
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Gene Diversity ◽  
Genetic Relationships ◽  
The United States ◽  
Mantel Test ◽  
Wild Oat ◽  
Chinese Populations ◽  
Nei's Distance ◽  
The Impact

Weed genetic diversity is important for understanding the ability of weeds to adapt to different environments and the impact of herbicide selection on weed populations. Genetic diversity within and among six wild oat populations in China varying in herbicide selection pressure and one population in North Dakota were surveyed using 64 polymorphic alleles resulting from 25 microsatellite loci. Mean Nei's gene diversity (h) for six wild oat populations from China was between 0.17 and 0.21, and total diversity (HT) was 0.23. A greater proportion of this diversity, however, was within (Hs= 0.19) rather than among (Gst= 0.15) populations. For the wild oat population from the United States,h= 0.24 andHT= 0.24 were comparable to the values for the six populations from China. Cluster analysis divided the seven populations into two groups, where one group was the United States population and the other group included the six Chinese populations. The genetic relationships among six populations from China were weakly correlated with their geographic distribution (r= 0.22) using the Mantel test. Minimal difference in gene diversity and small genetic distance (Nei's distance 0.07 or less) among six populations from China are consistent with wide dispersal of wild oat in the 1980s. Our results indicate that the wild oat populations in China are genetically diverse at a level similar to North America, and the genetic diversity of wild oat in the broad spatial scale is not substantially changed by environment, agronomic practices, or herbicide usage.

Site-specific wild oat (Avena fatua L.) management

2012 ◽  
Vol 92 (5) ◽  
pp. 923-931 ◽  
Author(s):  
H. J. Beckie ◽  
S. Shirriff
Keyword(s):  
Specific Treatment ◽  
Triticum Aestivum L ◽  
Avena Fatua ◽  
Slope Position ◽  
Wild Oat ◽  
Herbicide Application ◽  
Brassica Napus L ◽  
Site Specific ◽  
Lower Slope ◽  
Upper Slope

Beckie, H. J. and Shirriff, S. 2012. Site-specific wild oat ( Avena fatua L.) management. Can. J. Plant Sci. 92: 923–931. Variation in soil properties, such as soil moisture, across a hummocky landscape may influence wild oat emergence and growth. To evaluate wild oat emergence, growth, and management according to landscape position, a study was conducted from 2006 to 2010 in a hummocky field in the semiarid Moist Mixed Grassland ecoregion of Saskatchewan. The hypothesis tested was that wild oat emergence and growth would be greater in lower than upper slope positions under normal or dry early growing season conditions. Three herbicide treatments were imposed on the same plots each year of a 2-yr canola (Brassica napus L.) – wheat (Triticum aestivum L.) sequence: (1) nontreated (weedy) control; (2) herbicide application to upper and lower slope positions (i.e., full or blanket application); and (3) herbicide application to lower slope position only. Slope position affected crop and weed densities before in-crop herbicide application in years with dry spring growing conditions. Site-specific wild oat herbicide application in hummocky fields in semiarid regions may be justified based on results of wild oat control averaged across slope position. In year 2 of the crop sequence (wheat), overall (i.e., lower and upper slope) wild oat control based on density, biomass, and dockage (i.e., seed return) was similar between site-specific and full herbicide treatment in 2 of 3 yr. Because economic thresholds have not been widely adopted by growers in managing wild oat, site-specific treatment in years when conditions warrant may be an appropriate compromise between no application and blanket herbicide application.

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