scholarly journals THE BIOLOGY OF CANADIAN WEEDS.: 78. Galeopsis tetrahit L.

1987 ◽  
Vol 67 (3) ◽  
pp. 787-796 ◽  
Author(s):  
J. T. O’DONOVAN ◽  
M. P. SHARMA
Keyword(s):  
Soil Moisture ◽  
North America ◽  
Crop Yields ◽  
Weed Ecology ◽  
Weed Biology ◽  
Canadian Prairies ◽  
Brown Soil ◽  
Wide Range ◽  
Canadian Provinces ◽  
Crop Seed

Galeopsis tetrahit is an annual weed which was introduced to North America from Eurasia. It is present in all Canadian provinces and occupies a wide range of habitats including cultivated fields. It favors well-watered nutrient-rich soils and occurs infrequently in the drier brown soil zones of the southern Canadian prairies. Low soil moisture may be a major factor limiting its distribution and spread. It can reduce crop yields, contaminate crop seed and act as a reservoir for disease-causing organisms. A number of herbicides are available for its control.Key words: Hemp-nettle, Galeopsis tetrahit L., weed ecology, weed biology

scholarly journals Appraisal of SMAP Operational Soil Moisture Product from a Global Perspective

2020 ◽  
Vol 12 (12) ◽  
pp. 1977 ◽  
Author(s):  
Swati Suman ◽  
Prashant K. Srivastava ◽  
George P. Petropoulos ◽  
Dharmendra K. Pandey ◽  
Peggy E. O’Neill
Keyword(s):  
Soil Moisture ◽  
North America ◽  
Soil Layer ◽  
Product Evaluation ◽  
Global Scale ◽  
Global Perspective ◽  
Spatiotemporal Variability ◽  
Local Networks ◽  
Independent Verification ◽  
Wide Range

Space-borne soil moisture (SM) satellite products such as those available from Soil Moisture Active Passive (SMAP) offer unique opportunities for global and frequent monitoring of SM and also to understand its spatiotemporal variability. The present study investigates the performance of the SMAP L4 SM product at selected experimental sites across four continents, namely North America, Europe, Asia and Australia. This product provides global scale SM estimates at 9 km × 9 km spatial resolution at daily intervals. For the product evaluation, co-orbital in situ SM measurements were used, acquired at 14 test sites in North America, Europe, and Australia belonging to the International Soil Moisture Network (ISMN) and local networks in India. The satellite SM estimates of up to 0–5 cm soil layer were compared against collocated ground measurements using a series of statistical scores. Overall, the best performance of the SMAP product was found in North America (RMSE = 0.05 m3/m3) followed by Australia (RMSE = 0.08 m3/m3), Asia (RMSE = 0.09 m3/m3) and Europe (RMSE = 0.14 m3/m3). Our findings provide important insights into the spatiotemporal variability of the specific operational SM product in different ecosystems and environments. This study also furnishes an independent verification of this global product, which is of international interest given its suitability for a wide range of practical and research applications.

The biology of Canadian weeds. 106. Linaria dalmatica (L.) Mill.

1997 ◽  
Vol 77 (3) ◽  
pp. 483-491 ◽  
Author(s):  
Ksenija Vujnovic ◽  
Ross W. Wein
Keyword(s):  
North America ◽  
Vegetative Reproduction ◽  
The United States ◽  
Weed Biology ◽  
Linaria Dalmatica ◽  
Plant Parts ◽  
Leaf Surfaces ◽  
Dalmatian Toadflax ◽  
Canadian Provinces ◽  
The 1960S

Dalmatian Toadflax, Linaria dalmatica (L.) Mill. (Scrophulariaceae), is an important weed of rangelands, agricultural crops and waste areas in North America. The literature is less extensive than for the closely related yellow toadflax (Linaria vulgaris Mill.). Introduced from Eurasia as an ornamental plant into North America by 1894, it became naturalized in seven Canadian provinces and all of the United States of America west of the 100th meridian except for New Mexico. In North America it ranges from ca. 35° to 56°N latitude and it grows from near sea level to altitudes up to ca. 2800 m. Production of up to one-half million seeds per plant and its long-lived perennial nature make the species highly competitive and able to invade cropland and even stands of native ungrazed vegetation. Linaria dalmatica is a hemicryptophyte with strong vegetative reproduction and dormant seeds. Growth of creeping roots after removal of aboveground plant parts limits the effectiveness of control treatments such as grazing, clipping, mowing or burning. Several herbicides control the species for the short term; the smooth and waxy leaf surfaces may hinder herbicide uptake. Experimental biological control with insects since the 1960s shows promise. Key words: Linaria dalmatica, Dalmatian toadflax, Scrophulariaceae, weed biology, control, review

THE BIOLOGY OF CANADIAN WEEDS.: 75. Bromus tectorum L.

1986 ◽  
Vol 66 (3) ◽  
pp. 689-709 ◽  
Author(s):  
MAHESH K. UPADHYAYA ◽  
DOUGLAS McILVRIDE ◽  
ROY TURKINGTON
Keyword(s):  
British Columbia ◽  
North America ◽  
Bromus Tectorum ◽  
Downy Brome ◽  
Weed Biology ◽  
Intensive Research ◽  
Extensive Documentation ◽  
Competitive Success ◽  
Canadian Provinces ◽  
And Control

Bromus tectorum L. (downy brome), introduced to North America from Europe before 1861, has spread throughout most of the continent. It is present in all Canadian provinces except Newfoundland and is particularly abundant in southwestern Alberta and southern British Columbia. The ubiquitous nature of B. tectorum and its dual role as a serious weed and an important forage have resulted in extensive documentation on various aspects of its biology. Intensive research efforts have been expended in understanding its competitive success, and in implementing management and control practices. This paper reviews and summarizes literature on the biology of B. tectorum.Key words: Bromus tectorum, downy brome, cheatgrass, weed biology

THE BIOLOGY OF CANADIAN WEEDS. 94. Sonchus arvensis L.

1990 ◽  
Vol 70 (2) ◽  
pp. 509-532 ◽  
Author(s):  
WANDA K. LEMNA ◽  
CALVIN G. MESSERSMITH
Keyword(s):  
North America ◽  
Population Biology ◽  
Control Methods ◽  
Weed Biology ◽  
Glandular Hairs ◽  
Canadian Provinces ◽  
Sonchus Arvensis ◽  
And Control

Perennial sow-thistle (Sonchus arvensis L.) was introduced into North America from Europe and Asia and is distributed widely throughout the Canadian provinces. Two varieties are common; var. arvensis and var. glabrescens differ morphologically in the presence or absence of glandular hairs on peduncles and involucral bracts, respectively. Both varieties are common along roadsides and river and lake shores and in waste areas and cultivated fields throughout their introduced and native ranges. The perennial nature and ability to spread both by spreading roots and by seed make these weeds difficult to control. Details on the morphology, cytology, distribution, reproductive and population biology, and control methods are reviewed.Key words: Distribution, perennial sow-thistle, smooth perennial sow-thistle, weed biology

Assessment of the Role of Different Soil Properties on Crust Strength by Linear Regression Models

2019 ◽  
Vol 6 (04) ◽  
Author(s):  
MINAKSHI SERAWAT ◽  
V K PHOGAT ◽  
ANIL Abdul KAPOOR ◽  
VIJAY KANT SINGH ◽  
ASHA SERAWAT
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Properties ◽  
Crop Yields ◽  
Modulus Of Rupture ◽  
Silty Clay ◽  
Linear Regression Models ◽  
Wide Range ◽  
Dispersion Ratio ◽  
Crust Strength

Soil crust strength influences seedling emergence, penetration and morphology of plant roots, and, consequently, crop yields. A study was carried out to assess the role of different soil properties on crust strength atHisar, Haryana, India. The soil samples from 0-5 and 5-15 cm depths were collected from 21 locations from farmer’s fields, having a wide range of texture.Soil propertieswere evaluated in the laboratory and theirinfluence on the modulus of rupture (MOR), which is the measure of crust strength, was evaluated.The MOR of texturally different soils was significantly correlated with saturated hydraulic conductivity at both the depths. Dispersion ratio was found to decrease with an increase in fineness of the texture of soil and the lowest value was recorded in silty clay loam soil,which decreased with depth. The modulus of rupture was significantly negatively correlative with the dispersion ratio.There was no role of calcium carbonate in influencing the values of MOR of soils. Similarly,the influence of pH, EC and SAR of soil solution on MOR was non-significant.A perusal of thevalues of the correlations between MOR and different soil properties showed that the MOR of soils of Haryana are positively correlated with silt + clay (r = 0.805) followed by water-stable aggregates (r = 0.774), organic carbon (r = 0.738), silt (r = 0.711), mean weight diameter (r = 0.608) and clay (r = 0.593) while negatively correlated with dispersion ratio (r = - 0.872), sand (r = -0.801) and hydraulic conductivity (r = -0.752) of soils.

scholarly journals Global soil moisture data derived through machine learning trained with in-situ measurements

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Sungmin O. ◽  
Rene Orth
Keyword(s):  
Machine Learning ◽  
Soil Moisture ◽  
Large Scale ◽  
Short Term Memory ◽  
Temporal Dynamics ◽  
Soil Moisture Data ◽  
Wide Range ◽  
Global Soil

AbstractWhile soil moisture information is essential for a wide range of hydrologic and climate applications, spatially-continuous soil moisture data is only available from satellite observations or model simulations. Here we present a global, long-term dataset of soil moisture derived through machine learning trained with in-situ measurements, SoMo.ml. We train a Long Short-Term Memory (LSTM) model to extrapolate daily soil moisture dynamics in space and in time, based on in-situ data collected from more than 1,000 stations across the globe. SoMo.ml provides multi-layer soil moisture data (0–10 cm, 10–30 cm, and 30–50 cm) at 0.25° spatial and daily temporal resolution over the period 2000–2019. The performance of the resulting dataset is evaluated through cross validation and inter-comparison with existing soil moisture datasets. SoMo.ml performs especially well in terms of temporal dynamics, making it particularly useful for applications requiring time-varying soil moisture, such as anomaly detection and memory analyses. SoMo.ml complements the existing suite of modelled and satellite-based datasets given its distinct derivation, to support large-scale hydrological, meteorological, and ecological analyses.

scholarly journals A Cross-sectional Survey of the North American Skull Base Society: Current Practice Patterns of Vestibular Schwannoma Evaluation and Management in North America

2017 ◽  
Vol 79 (03) ◽  
pp. 289-296 ◽  
Author(s):  
Jamie Van Gompel ◽  
R. Wiet ◽  
Nicole Tombers ◽  
Anand Devaiah ◽  
Devyani Lal ◽  
...  
Keyword(s):  
North America ◽  
Skull Base ◽  
Vestibular Schwannoma ◽  
North American ◽  
Management Practices ◽  
Current Practice ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Number Of Patients ◽  
Wide Range

Background Very few studies have examined vestibular schwannoma (VS) management trends across centers and between providers. The objective of this study is to examine current practice trends, variance in treatment philosophies, and nuanced or controversial aspects of VS care across North America. Methods This is a cross-sectional survey of North American Skull Base Society (NASBS) members who report regular involvement in VS care. Results A total of 57 completed surveys were returned. Most respondents claimed to have over 20 years of experience and the majority reported working in an academic practice with an affiliated otolaryngology and/or neurosurgery residency program. Sixty-three percent of respondents claimed to evaluate VS patients in clinic with both an otolaryngologist and neurosurgeon involved. Eighty-six percent of respondents claimed to operate on VS with both an otolaryngologist and neurosurgeon involved, while only 18% of neurosurgeons and 9% of otolaryngologists performed surgery alone. There was a wide range in the number of cases evaluated at each center annually. Similarly, there was wide variation in the number of patients treated with microsurgery and radiation at each center. Additional details regarding management preferences for microsurgery, stereotactic radiosurgery, stereotactic radiotherapy, and conservative observation are presented. Conclusion VS management practices vary between providers and centers. Overall, most centers employ a multidisciplinary approach to management with collaboration between otolaryngology and neurosurgery. Overall, survey responses concur with previous studies suggesting a shift toward conservatism in management.

Economics of rotation and tillage systems for the Dark Brown soil zone of the Canadian Prairies

1992 ◽  
Vol 24 (3) ◽  
pp. 271-284 ◽  
Author(s):  
R.P. Zentner ◽  
S.A. Brandt ◽  
K.J. Kirkland ◽  
C.A. Campbell ◽  
G.J. Sonntag
Keyword(s):  
Tillage Systems ◽  
Canadian Prairies ◽  
Brown Soil ◽  
Soil Zone

A generally applicable pedotransfer function that estimates field capacity and permanent wilting point from soil texture and bulk density

2008 ◽  
Vol 88 (5) ◽  
pp. 761-774 ◽  
Author(s):  
J. A. P. Pollacco
Keyword(s):  
Organic Matter ◽  
Soil Moisture ◽  
Bulk Density ◽  
Soil Texture ◽  
The United States ◽  
Pedotransfer Functions ◽  
Pedotransfer Function ◽  
Data Set ◽  
Wide Range ◽  
Fitting Parameters

Hydrological models require the determination of fitting parameters that are tedious and time consuming to acquire. A rapid alternative method of estimating the fitting parameters is to use pedotransfer functions. This paper proposes a reliable method to estimate soil moisture at -33 and -1500 kPa from soil texture and bulk density. This method reduces the saturated moisture content by multiplying it with two non-linear functions depending on sand and clay contents. The novel pedotransfer function has no restrictions on the range of the texture predictors and gives reasonable predictions for soils with bulk density that varies from 0.25 to 2.16 g cm-3. These pedotransfer functions require only five parameters for each pressure head. It is generally accepted that the introduction of organic matter as a predictor improves the outcomes; however it was found by using a porosity based pedotransfer model, using organic matter as a predictor only modestly improves the accuracy. The model was developed employing 18 559 samples from the IGBP-DIS soil data set for pedotransfer function development (Data and Information System of the International Geosphere Biosphere Programme) database that embodies all major soils across the United States of America. The function is reliable and performs well for a wide range of soils occurring in very dry to very wet climates. Climatical grouping of the IGBP-DIS soils was proposed (aquic, tropical, cryic, aridic), but the results show that only tropical soils require specific grouping. Among many other different non-climatical soil groups tested, only humic and vitric soils were found to require specific grouping. The reliability of the pedotransfer function was further demonstrated with an independent database from Northern Italy having heterogeneous soils, and was found to be comparable or better than the accuracy of other pedotransfer functions found in the literature. Key words: Pedotransfer functions, soil moisture, soil texture, bulk density, organic matter, grouping

scholarly journals North American channel catfish, Ictalurus punctatus: a neglected but potentially invasive freshwater fish species?

2021 ◽  
Vol 23 (5) ◽  
pp. 1563-1576 ◽  
Author(s):  
Phillip J. Haubrock ◽  
Gordon H. Copp ◽  
Iva Johović ◽  
Paride Balzani ◽  
Alberto F. Inghilesi ◽  
...  
Keyword(s):  
North America ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
North American ◽  
Disease Transmission ◽  
Native Species ◽  
Assessment Protocol ◽  
South Italy ◽  
Wide Range ◽  
North And South

AbstractThe North American channel catfish Ictalurus punctatus has been introduced to several locations in Europe but has received little or no scientific study despite its invasive attributes, including prolific reproduction, tolerance to a wide range of conditions, opportunistic feeding, at least partial ‘predator release’, and some evidence of environmental impacts (e.g. disease transmission). To assess the species’ potential invasiveness and the likely risks to native species and ecosystems in Europe, available literature from both North America and Europe was reviewed and used to carry out risk screenings of the species for the risk assessment areas, North and South Italy, using the Aquatic Invasiveness Screening Kit (AS-ISK), which was followed by a more detailed evaluation (for both North America and Europe) of the species’ potential impacts using the Environmental Impact Classification of Alien Taxa (EICAT) assessment protocol. The AS-ISK score indicated that channel catfish is likely to pose a high risk of being invasive in both North and South Italy, with EICAT scores indicating “Major” impacts for both North America and Europe, at high and medium confidence levels, respectively. The present results emphasise the urgent need to carry out in-depth studies on introduced populations of this species to understand better its invasive potential so as to inform management decisions on the appropriate control or eradication measures for invaded water bodies.

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