scholarly journals Climatic Effects on Sweetpotato Yield in Southern Ontario

HortScience ◽  
2000 ◽  
Vol 35 (4) ◽  
pp. 570A-570
Author(s):  
A.W. McKeown
Keyword(s):  
Potential Evapotranspiration ◽  
Warm Season ◽  
The United States ◽  
Climatic Conditions ◽  
Vegetable Crops ◽  
Climatic Effects ◽  
Southern Ontario ◽  
The North ◽  
Ipomea Batatas ◽  
Wide Range

Sweetpotato (Ipomea batatas L) was one crop chosen for development in Ontario in response to demand for alternative crops to tobacco and increasing demand for nontraditional vegetables. A wide range of vegetable crops can be grown in the sandy soils on the north shore of lake Erie. In 1999, there were ≈75 acres of sweetpotatoes grown in Ontario. Lack of an early cultivar to fit a short, warm season was a factor limiting production of sweetpotatoes in southern Ontario. Over an 11–growing season period, cultivars of sweetpotato from several breeding programs in the United States were evaluated for suitability to Ontario climatic conditions. Planting to harvest date season totals for heat units, precipitation, vapor pressure deficit (VPD), potential evapotranspiration, and solar radiation were calculated. Yield was regressed on these climatic variables using multiple linear regression. Of the cultivars evaluated, `Beauregard' replaced `Jewel' as the local industry standard after one season's evaluation. Of the numbered lines evaluated, NC9317 appears suitable for commercial trials. Yields varied greatly among years, and the seasonal VPD explained the largest amount of variation in year-to-year yield. Cultivars vary in their response to seasonal VPD. Yield of `Beauregard' increased with increasing seasonal VPD while NC9317 decreased. Cultivars require ability to yield in a short season and the ability to consistently produce under a range of atmospheric VPDs dictated by interannual climatic variation.

scholarly journals Quebec’s Economic and Commercial Linkages with the United States, 1994–2017

2017 ◽  
Author(s):  
Earl H. Fry
Keyword(s):  
United States ◽  
Trade Agreement ◽  
The United States ◽  
The North ◽  
Nation States ◽  
Wide Range ◽  
The Us ◽  
Us Government ◽  
Big Picture ◽  
The Impact

This article examines the ebb and flow of the Quebec government’s economic and commercial relations with the United States in the period 1994–2017. The topic demonstrates the impact of three major forces on Quebec’s economic and commercial ties with the US: (1) the North American Free Trade Agreement (NAFTA) which became operational in 1994 and was fully implemented over a 15-year period; (2) the onerous security policies put in place by the US government in the decade following the horrific events of 11 September 2001; and (3) changing economic circumstances in the United States ranging from robust growth to the worst recession since the Great Depression of the 1930s. The article also indicates that the Quebec government continues to sponsor a wide range of activities in the United States, often more elaborate and extensive than comparable activities pursued by many nation-states with representation in the US. 1 1 Stéphane Paquin, ‘Quebec-U.S. Relations: The Big Picture’, American Review of Canadian Studies 46, no. 2 (2016): 149–61.

scholarly journals Surface predictor of overturning circulation and heat content change in the subpolar North Atlantic

Ocean Science ◽  
2019 ◽  
Vol 15 (3) ◽  
pp. 809-817 ◽  
Author(s):  
Damien G. Desbruyères ◽  
Herlé Mercier ◽  
Guillaume Maze ◽  
Nathalie Daniault
Keyword(s):  
North Atlantic ◽  
Spatial Scales ◽  
Low Frequency ◽  
Heat Content ◽  
Climatic Conditions ◽  
Meridional Overturning Circulation ◽  
Overturning Circulation ◽  
The North ◽  
Wide Range ◽  
Key Aspects

Abstract. The Atlantic Meridional Overturning Circulation (AMOC) impacts ocean and atmosphere temperatures on a wide range of temporal and spatial scales. Here we use observational datasets to validate model-based inferences on the usefulness of thermodynamics theory in reconstructing AMOC variability at low frequency, and further build on this reconstruction to provide prediction of the near-future (2019–2022) North Atlantic state. An easily observed surface quantity – the rate of warm to cold transformation of water masses at high latitudes – is found to lead the observed AMOC at 45∘ N by 5–6 years and to drive its 1993–2010 decline and its ongoing recovery, with suggestive prediction of extreme intensities for the early 2020s. We further demonstrate that AMOC variability drove a bi-decadal warming-to-cooling reversal in the subpolar North Atlantic before triggering a recent return to warming conditions that should prevail at least until 2021. Overall, this mechanistic approach of AMOC variability and its impact on ocean temperature brings new key aspects for understanding and predicting climatic conditions in the North Atlantic and beyond.

The effect of human influence on wet and dry European summers

2021 ◽  
Author(s):  
Nikolaos Christidis ◽  
Peter Stott
Keyword(s):  
Climate Change ◽  
Potential Evapotranspiration ◽  
Rainfall Variability ◽  
Climatic Conditions ◽  
Drought Indices ◽  
Human Influence ◽  
The North ◽  
Detection And Attribution ◽  
Standardised Precipitation Index ◽  
Dry Conditions

<p>As the climate becomes warmer under the influence of anthropogenic forcings, increases in the concentration of the atmospheric water vapour may lead to an intensification of wet and dry extremes. Understanding regional hydroclimatic changes can provide actionable information to help communities adapt to impacts specific to their location. This study employs an ensemble of 9 CMIP6 models and compares experiments with and without the effect of human influence using detection and attribution methodologies. The analysis employs two popular drought indices: the rainfall-based standardised precipitation index (SPI), and its extension, the standardized precipitation evapotranspiration index (SPEI), which also accounts for changes in potential evapotranspiration. Both indices are defined relative to the pre-industrial climate, which enables a comparison between past, present and future climatic conditions. Potential evapotranspiration is computed with the simple, temperature-based, Thornthwaite formula. The latter has been criticised for omitting the influences of radiation, humidity and wind, but has been shown to yield very similar trends, spatial averages and correlations with more sophisticated models. It is therefore deemed to be adequate in studies assessing the broader overall effect of climate change, which are more concerned with wet and dry trends and changes in characteristics of extremes rather than the precise estimation of drought index values. The rainfall-based index suggests a shift towards wetter conditions in the north and dryer in the south of the continent, as well as an overall increase in variability. Nevertheless, when the temperature effect is included, the wet trends in the north are largely masked leading to increasingly drier summers across most of the continent. A formal statistical methodology indicates that the fingerprint of forced climate change has emerged above variability and is thus detectable in the observational trends of both indices. A broadening of the SPI distribution also suggests higher rainfall variability in a warmer climate. The study demonstrates a striking drying trend in the Mediterranean region, suggesting that what were extremely dry conditions there in the pre-industrial climate may become normal by the end of the century.</p>

scholarly journals Wetlands inform how climate extremes influence surface water expansion and contraction

2018 ◽  
Vol 22 (3) ◽  
pp. 1851-1873 ◽  
Author(s):  
Melanie K. Vanderhoof ◽  
Charles R. Lane ◽  
Michael G. McManus ◽  
Laurie C. Alexander ◽  
Jay R. Christensen
Keyword(s):  
Surface Water ◽  
Potential Evapotranspiration ◽  
Landsat Imagery ◽  
The United States ◽  
Climatic Conditions ◽  
Water Dynamics ◽  
Water Quantity ◽  
Landscape Characteristics ◽  
Connected Surface ◽  
The Relationship

Abstract. Effective monitoring and prediction of flood and drought events requires an improved understanding of how and why surface water expansion and contraction in response to climate varies across space. This paper sought to (1) quantify how interannual patterns of surface water expansion and contraction vary spatially across the Prairie Pothole Region (PPR) and adjacent Northern Prairie (NP) in the United States, and (2) explore how landscape characteristics influence the relationship between climate inputs and surface water dynamics. Due to differences in glacial history, the PPR and NP show distinct patterns in regards to drainage development and wetland density, together providing a diversity of conditions to examine surface water dynamics. We used Landsat imagery to characterize variability in surface water extent across 11 Landsat path/rows representing the PPR and NP (images spanned 1985–2015). The PPR not only experienced a 2.6-fold greater surface water extent under median conditions relative to the NP, but also showed a 3.4-fold greater change in surface water extent between drought and deluge conditions. The relationship between surface water extent and accumulated water availability (precipitation minus potential evapotranspiration) was quantified per watershed and statistically related to variables representing hydrology-related landscape characteristics (e.g., infiltration capacity, surface storage capacity, stream density). To investigate the influence stream connectivity has on the rate at which surface water leaves a given location, we modeled stream-connected and stream-disconnected surface water separately. Stream-connected surface water showed a greater expansion with wetter climatic conditions in landscapes with greater total wetland area, but lower total wetland density. Disconnected surface water showed a greater expansion with wetter climatic conditions in landscapes with higher wetland density, lower infiltration and less anthropogenic drainage. From these findings, we can expect that shifts in precipitation and evaporative demand will have uneven effects on surface water quantity. Accurate predictions regarding the effect of climate change on surface water quantity will require consideration of hydrology-related landscape characteristics including wetland storage and arrangement.

scholarly journals An 18-year climatology of derechos in Germany

2020 ◽  
Vol 20 (5) ◽  
pp. 1335-1351 ◽  
Author(s):  
Christoph P. Gatzen ◽  
Andreas H. Fink ◽  
David M. Schultz ◽  
Joaquim G. Pinto
Keyword(s):  
Mixed Layer ◽  
Convective Available Potential Energy ◽  
Vertical Wind Shear ◽  
Warm Season ◽  
The United States ◽  
Cold Season ◽  
Start Time ◽  
Central Germany ◽  
The North ◽  
Wind Events

Abstract. Derechos are high-impact convective wind events that can cause fatalities and widespread losses. In this study, 40 derechos affecting Germany between 1997 and 2014 are analyzed to estimate the derecho risk. Similar to the United States, Germany is affected by two derecho types. The first, called warm-season-type derechos, form in strong southwesterly 500 hPa flow downstream of western European troughs and account for 22 of the 40 derechos. They have a peak occurrence in June and July. Warm-season-type derechos frequently start in the afternoon and move either eastward along the Alpine forelands or northeastward across southern central Germany. Associated proximity soundings indicate strong 0–6 and 0–3 km vertical wind shear and a median of mixed-layer convective available potential energy (mixed-layer CAPE) around 500 J kg−1. The second derecho type, the cold-season-type derecho, forms in strong northwesterly 500 hPa flow, frequently in association with mid-tropospheric potential vorticity (PV) intrusions, and accounts for 18 of the 40 derechos. They are associated with a secondary peak from December to February. Cold-season-type derechos start over or close to the North Sea and primarily affect northern and central Germany; their start time is not strongly related to the peak of diurnal heating. Proximity soundings indicate high-shear–low-CAPE environments. A total of 15 warm-season-type and 9 cold-season-type derechos had wind gusts reaching 33 m s−1 in at least three locations. Although warm-season derechos are more frequent, the path length of cold-season-type derechos is on average 1.4 times longer. Thus, these two types of German derechos are likely to have similar impacts.

scholarly journals Model parameters of four important vegetable crops for improved water use and yield estimation

Water SA ◽  
2018 ◽  
Vol 44 (4 October) ◽  
Author(s):  
JT Vahrmeijer ◽  
JG Annandale ◽  
JM Steyn ◽  
KL Bristow
Keyword(s):  
Water Use ◽  
Growth Parameters ◽  
Water Productivity ◽  
Resource Planning ◽  
Crop Growth ◽  
Climatic Conditions ◽  
Model Parameters ◽  
Vegetable Production ◽  
Vegetable Crops ◽  
Wide Range

High-value vegetable crops are typically grown under irrigation to reduce production risk. For water resource planning it is essential to be able to accurately estimate water use of irrigated crops under a wide range of climatic conditions. Crop water use models provide a means to make water use and yield estimates, but need crop- and even cultivar-specific parameters. There is generally a lack of crop-specific model parameters for some important commercially grown vegetable crops, especially parameters determined over both summer and winter seasons. The experimental site used in this study was on the Steenkoppies Aquifer, a catchment under stress and an important vegetable production area in South Africa. Crop-specific growth parameters and water use for 4 selected high-value vegetable crops (beetroot, cabbage, carrots and broccoli) were measured over multiple seasons (two summers and one winter). These were used to parameterise the Soil Water Balance (SWB) generic crop growth model for both summer and winter seasons. In seasons where the same cultivar was planted, a single set of model parameters could be used to successfully simulate crop growth and water use. Results show that the amount of irrigation water required is dependent on season and rainfall, with broccoli having the lowest (1.8–2.7 kg m−3) and beetroot the highest (12.2–23.4 kg m−3) water productivity (WPFM), defined as fresh mass of marketable product per unit water consumed. The root crops had a greater harvest index (HIDM) than cabbage and broccoli. The parameters obtained expand the current database of SWB crop growth parameters for vegetables and can be used in a wide range of mechanistic simulation models to improve water management at field and catchment levels.

Chemical and Biological Control of Downy Brome (Bromus tectorum) in Wheat and Alfalfa in North America

Weed Science ◽  
1984 ◽  
Vol 32 (S1) ◽  
pp. 18-25 ◽  
Author(s):  
Thomas F. Peeper
Keyword(s):  
Winter Wheat ◽  
New England ◽  
Bromus Tectorum ◽  
The United States ◽  
Climatic Conditions ◽  
Annual Rainfall ◽  
Alkaline Soils ◽  
Downy Brome ◽  
Wide Range ◽  
Red Winter Wheat

As an agrestal weed, downy brome (Bromus tectorumL. # BROTE) is most troublesome in winter wheat (Triticum aestivumL. # TRIAE) and alfalfa (Medicago sativaL. # MEDSA) because of the ability of downy brome to reproduce prior to crop harvesting (70, 76). Geographically, downy brome is most common in the western half of the United States where annual rainfall totals 15 to 55 cm and autumn rainfall ranges from 5 to 12 cm (10, 11, 86, 98). In contrast, cheat (Bromus secalinusL. # BROSE) is more common in the eastern portion of the hard red winter wheat producing regions and in the more humid soft red winter wheat region. Behrendt and Hanf (12) state that cheat has been more common on acid sandy or loamy soils while downy brome commonly occurs on dry, mostly alkaline, sandy to loamy soils. Since soils are frequently alkaline in the relatively dry climate of the western regions (61), it is not clear exactly what role pH plays in affecting geographical distribution of the variousBromusspp. Recent serious problems with downy brome in the New England nursery industry (69) and orchards (57) indicate that downy brome could thrive under a relatively wide range of edaphic and climatic conditions. However, as a weed problem in wheat, the common prevalent conditions of low annual precipitation and alkaline soils should not go unnoticed in the development of chemical weed control practices.

scholarly journals Advances in Research on Phytophthora capsici on Vegetable Crops in The United States

Plant Disease ◽  
2012 ◽  
Vol 96 (11) ◽  
pp. 1588-1600 ◽  
Author(s):  
Leah L. Granke ◽  
Lina Quesada-Ocampo ◽  
Kurt Lamour ◽  
Mary K. Hausbeck
Keyword(s):  
Host Range ◽  
Phytophthora Capsici ◽  
The United States ◽  
Fruit Rot ◽  
Economic Losses ◽  
Future Research ◽  
Vegetable Crops ◽  
Long Distance ◽  
Term Survival ◽  
Wide Range

Since L. H. Leonian's first description of Phytophthora capsici as a pathogen of chile pepper in 1922, we have made many advances in our understanding of this pathogen's biology, host range, dissemination, and management. P. capsici causes foliar blighting, damping-off, wilting, and root, stem, and fruit rot of susceptible hosts, and economic losses are experienced annually in vegetable crops including cucurbits and peppers. Symptoms of P. capsici infection may manifest as stunting, girdling, or cankers for some cultivars or crops that are less susceptible. P. capsici continues to be a constraint on production, and implementation of an aggressive integrated management scheme can still result in insufficient control when weather is favorable for disease. Management of diseases caused by P. capsici is currently limited by the long-term survival of the pathogen as oospores in the soil, a wide host range, long-distance movement of the pathogen in surface water used for irrigation, the presence of fungicide-resistant pathogen populations, and a lack of commercially acceptable resistant host varieties. P. capsici can infect a wide range of hosts under laboratory and greenhouse conditions including cultivated crops, ornamentals, and native plants belonging to diverse plant families. As our understanding of P. capsici continues to grow, future research should focus on developing novel and effective solutions to manage this pathogen and prevent economic losses due to the diseases it causes.

scholarly journals On the Relationship between Spring NAO and Snowmelt in the Upper Southwestern United States

2017 ◽  
Vol 30 (14) ◽  
pp. 5141-5149 ◽  
Author(s):  
Boksoon Myoung ◽  
Seung Hee Kim ◽  
Jinwon Kim ◽  
Menas C. Kafatos
Keyword(s):  
United States ◽  
Southern Oscillation ◽  
Warm Season ◽  
Weather Conditions ◽  
Underlying Mechanism ◽  
The United States ◽  
The North ◽  
The North Atlantic Oscillation ◽  
The Relationship ◽  
Spring Snowmelt

This study examines the relationship between the North Atlantic Oscillation (NAO) and snowmelt in spring in the upper southwestern states of the United States (UP_SW) including California, Nevada, Utah, and Colorado, using SNOTEL datasets for 34 yr (1980–2014). Statistically significant negative correlations are found between NAO averages in the snowmelt period and timings of snowmelt (i.e., positive NAO phases in spring enhance snowmelt, and vice versa). It is also found that correlations between El Niño–Southern Oscillation and snowmelt are negligible in the region. The NAO–snowmelt relationship is most pronounced below the 2800-m level; above this level, the relationship becomes weaker. The underlying mechanism for this link is that a positioning of upper-tropospheric anticyclonic (cyclonic) circulations over the western United States that are associated with development of the positive (negative) NAO phases tends to bring warmer and drier (colder and wetter) spring weather conditions to the region. The temperature variations related with the NAO phases also strongly modulate the snowfall–rainfall partitioning. The relationship between the NAO and spring snowmelt can serve as key information for the warm season water resources management in the UP_SW.

scholarly journals Leek Cultivation Guide for Florida

EDIS ◽  
2020 ◽  
Vol 2020 (5) ◽  
Author(s):  
Mary Dixon ◽  
Guodong Liu
Keyword(s):  
United States ◽  
Nutrient Content ◽  
The United States ◽  
Climatic Conditions ◽  
Allium Porrum ◽  
Vegetable Crops ◽  
Ornamental Crops

Leek (Allium porrum L.) is a member of Amaryllidaceae, a family with ornamental crops, like amaryllis, and with vegetable crops, like onion. Leek is a highly demanded vegetable because of its flavor and nutrient content. Although there is great potential for leek to be grown commercially in Florida due to demand and appropriate climatic conditions, the United States does not currently produce a significant quantity of leek compared to countries such as Indonesia, Turkey, and China. This new 7-page publication of the UF/IFAS Horticultural Sciences Department, written by Mary Dixon and Guodong Liu, provides a basic guide to cultivation of leek in Florida, as well as information on its agricultural, culinary, and medicinal uses.https://edis.ifas.ufl.edu/hs1388

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