EFFECTS OF SULPHATE AND CHLORIDE SOIL SALINITY ON GROWTH AND NEEDLE COMPOSITION OF SIBERIAN LARCH

1980 ◽  
Vol 60 (3) ◽  
pp. 903-910 ◽  
Author(s):  
M. R. CARTER
Keyword(s):  
Electrical Conductivity ◽  
Root Growth ◽  
Siberian Larch ◽  
Field Studies ◽  
Physiological Effect ◽  
Chloride Anion ◽  
Salt Tolerant ◽  
Canadian Prairies ◽  
Naturally Occurring ◽  
Chloride Salinity

Greenhouse and field studies were conducted to assess the salinity tolerance of Siberian larch (Larix siberica L.) under conditions found on the Canadian prairies. In greenhouse studies top and root growth of Siberian larch seedlings began to decline under sulphate salinity between 2.0 and 5.3 mmhos/cm (electrical conductivity of saturation paste extract) indicating that Siberian larch is moderately salt-tolerant. The addition of chloride caused an initial top growth decrease, chlorosis, and reduction in survival between 1.4 and 3.6 mmhos/cm; the latter salinity level being associated with 20 meq/L of Cl and 1.5% Cl in the saturation paste extract and needles, respectively. Field studies conducted under naturally occurring sulphate salinity indicated that height of 10-yr-old Siberian larch began to decline between 3.5 and 4.0 mmhos/cm. Changes in needle mineral composition were related to the ratio or increase of ions in the soil solution, and the physiological effect of the sulphate and chloride anion. In general, presence of chloride salinity caused a greater increase to occur in the cation content of the needles than sulphate salinity. Accumulation of organic anions in the needles was also related to cation concentration and needle chlorosis.

scholarly journals Evaluating the Impact of Two Generalist Predators on the Leafhopper Erasmoneura vulnerata Population Density

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 321
Author(s):  
Stefan Cristian Prazaru ◽  
Giulia Zanettin ◽  
Alberto Pozzebon ◽  
Paola Tirello ◽  
Francesco Toffoletto ◽  
...  
Keyword(s):  
Field Experiments ◽  
Field Studies ◽  
Generalist Predators ◽  
Predator Species ◽  
Potted Plants ◽  
Naturally Occurring ◽  
Orius Majusculus ◽  
Limited Effectiveness ◽  
Pest Outbreaks ◽  
The Impact

Outbreaks of the Nearctic leafhopper Erasmoneura vulnerata represent a threat to vinegrowers in Southern Europe, in particular in North-eastern Italy. The pest outbreaks are frequent in organic vineyards because insecticides labeled for organic viticulture show limited effectiveness towards leafhoppers. On the other hand, the naturally occurring predators and parasitoids of E. vulnerata in vineyards are often not able to keep leafhopper densities at acceptable levels for vine-growers. In this study, we evaluated the potential of two generalist, commercially available predators, Chrysoperla carnea and Orius majusculus, in suppressing E. vulnerata. Laboratory and semi-field experiments were carried out to evaluate both species’ predation capacity on E. vulnerata nymphs. The experiments were conducted on grapevine leaves inside Petri dishes (laboratory) and on potted and caged grapevines (semi-field); in both experiments, the leaves or potted plants were infested with E. vulnerata nymphs prior to predator releases. Both predator species exhibited a remarkable voracity and significantly reduced leafhopper densities in laboratory and semi-field experiments. Therefore, field studies were carried out over two growing seasons in two vineyards. We released 4 O. majusculus adults and 30 C. carnea larvae per m2 of canopy. Predator releases in vineyards reduced leafhopper densities by about 30% compared to the control plots. Results obtained in this study showed that the two predators have a potential to suppress the pest density, but more research is required to define appropriate predator–prey release ratios and release timing. Studies on intraguild interactions and competition with naturally occurring predators are also suggested.

scholarly journals Evolution of halophytes: multiple origins of salt tolerance in land plants

2010 ◽  
Vol 37 (7) ◽  
pp. 604 ◽  
Author(s):  
Timothy J. Flowers ◽  
Hanaa K. Galal ◽  
Lindell Bromham
Keyword(s):  
Salt Tolerance ◽  
Novel Species ◽  
Complex Trait ◽  
Land Plants ◽  
Salt Tolerant ◽  
Physiological Mechanisms ◽  
Multiple Origins ◽  
Naturally Occurring ◽  
Tolerant Plants

The evolution of salt tolerance is interesting for several reasons. First, since salt-tolerant plants (halophytes) employ several different mechanisms to deal with salt, the evolution of salt tolerance represents a fascinating case study in the evolution of a complex trait. Second, the diversity of mechanisms employed by halophytes, based on processes common to all plants, sheds light on the way that a plant’s physiology can become adapted to deal with extreme conditions. Third, as the amount of salt-affected land increases around the globe, understanding the origins of the diversity of halophytes should provide a basis for the use of novel species in bioremediation and conservation. In this review we pose the question, how many times has salt tolerance evolved since the emergence of the land plants some 450–470 million years ago? We summarise the physiological mechanisms underlying salt-tolerance and provide an overview of the number and diversity of salt-tolerant terrestrial angiosperms (defined as plants that survive to complete their life cycle in at least 200 mM salt). We consider the evolution of halophytes using information from fossils and phylogenies. Finally, we discuss the potential for halophytes to contribute to agriculture and land management and ask why, when there are naturally occurring halophytes, it is proving to be difficult to breed salt-tolerant crops.

scholarly journals Effect of Sulfur and Clean Salt on Antioxidant Enzymes and Proline Content in Improving Salt Tolerance of Two Lettuce Cultivars Grown in Basrah

2019 ◽  
Vol 32 ◽  
pp. 80-89
Author(s):  
Jameel H. Hiji ◽  
Abbas M. Jasim ◽  
Awatif N. Jerry
Keyword(s):  
Electrical Conductivity ◽  
Antioxidant Enzymes ◽  
Salt Tolerance ◽  
Adverse Effects ◽  
Irrigation Water ◽  
Sandy Loam ◽  
Proline Content ◽  
Salt Tolerant ◽  
Loam Soil

The experiment was conducted during 2017-2018 and 2018-2019 winter seasons at Abu Al-Khaseeb District at basrah /Iraq on sandy loam soil  to study the effect of sulfur at five concentration ( 0 , 500 , 1000, 1500 and 2000) kg. Ha-1, clean salt at three concentration (0, 0.5 and 1.0) ml. L-1, two cultivars of lettuce local and fajr and interaction among them  at electrical conductivity of the irrigation water (7.85 and 9.69) dS.m-1.  Result showed significant reduction in the activity of catalase (CAT) and peroxidase (POD) enzymes and proline content in all treatments of sulfur and clean salt especially at 2000 Kg. Ha-1 sulfur and clean salt at 1.0 ml L-1had significantly decrease in CAT activity (295.80 ? 341.65) U mg–1 FW, POD activity (7.86? 8.98) U mg–1 FW and proline (0.50 ? 0.80) mg g-1DW, comparing with control of CAT activity (663.21, 814.65) U mg–1 FW and POD activity (13.83, 15.52) mg–1 FW and proline (1.19, 2.03) mg g-1DW, respectively for two seasons due to the role of sulfur and clean salt ameliorates the adverse effects of salinity on plants. Fajr lettuce is more salt-tolerant than local due to less antioxidant enzyme levels POD, CAT and proline.

Herbicide-Resistant Canola (Brassica napus) Response and Weed Control with Postemergence Herbicides

2006 ◽  
Vol 20 (3) ◽  
pp. 551-557 ◽  
Author(s):  
Timothy L. Grey ◽  
Paul L. Raymer ◽  
David C. Bridges
Keyword(s):  
Weed Control ◽  
Field Studies ◽  
Italian Ryegrass ◽  
Wild Radish ◽  
Application Timing ◽  
Herbicide Resistant ◽  
Naturally Occurring ◽  
And Control ◽  
Postemergence Herbicides ◽  
Significant Injury

Field studies were conducted to evaluate weed control in herbicide-resistant canola in Georgia. The resistant canola cultivars and respective herbicides were ‘Pioneer 45A76’ and imazamox, ‘Hyola 357RR’ and glyphosate, and ‘2573 Invigor’ and glufosinate. Weed seed of Italian ryegrass and wild radish were sown simultaneously in October with canola and control of these species was evaluated along with other naturally occurring weeds. Herbicide treatments for the respective herbicide-resistant canola cultivar were imazamox at 0.035 and 0.071 kg ai/ha, glyphosate at 0.84 and 1.64 kg ae/ha, and glufosinate at 0.5 and 1.0 kg ai/ha. Herbicides were applied at one– two-leaf (LF) and three–four-LF canola stages. There was no significant injury to any canola cultivar as a result of herbicide rate or timing of application. By midseason (February), imazamox effectively controlled wild radish, henbit, and shepherd's-purse at both rates and at both timings. When applied to three–four-LF canola, the higher rates of glyphosate and glufosinate were required to provide 75% or greater control of Italian ryegrass, wild garlic, and henbit. Glufosinate did not adequately control wild radish at either rate or application timing. Greenhouse experiments provided similar results.

scholarly journals Recent Advances in Ice Mechanics in Canada

1987 ◽  
Vol 40 (9) ◽  
pp. 1214-1231 ◽  
Author(s):  
N. K. Sinha ◽  
G. W. Timco ◽  
R. Frederking
Keyword(s):  
Physical Modelling ◽  
Field Studies ◽  
Material Structure ◽  
Naturally Occurring ◽  
Extensive Field ◽  
Strength And Deformation ◽  
Work Done ◽  
Ice Forces ◽  
Analytical Expressions

Work on the mechanics of ice, which has been carried forward on a broad front in Canada, has resulted in a number of significant advances in the last 10 years. The factors influencing the growth of various types of sea ice have been quantified fundamentally and methods for examining the resulting material structure have been developed. Extensive work has been done on strength and deformation characteristics of ice. A significant effort has been the development of analytical expressions to describe the rheological behavior of ice. Elastic modulus, Poisson’s ratio, and creep were also treated. A great deal has been done on measuring the compressive strength of various types of naturally occurring ice and subsequently these data were combined into a suitable description of a failure envelope. Work has also been done on measuring the flexural strength, shear strength, adhesion and fracture toughness. Methods for laboratory testing and in situ measurements of mechanical properties have been developed. The problem of defining ice forces on structures has been the primary motivation for research on ice. Analytical modelling, physical modelling, laboratory studies and very extensive field studies have been used. Work done in this area has included development of methods and their application to actual problems and has benefitted greatly from the integration of all four approaches. Very significant progress has been made. Ice and ice covers have been successfully used to support various offshore activities: drilling off floating ice platforms, stabilizing grounded rubble fields to protect structures and transporting large loads over ice.

scholarly journals Zoysiagrass Establishment from Sprigs following Application of Herbicides, Nitrogen, and a Biostimulator

HortScience ◽  
1996 ◽  
Vol 31 (6) ◽  
pp. 972-975 ◽  
Author(s):  
M.J. Carroll ◽  
P.H. Dernoeden ◽  
J.M. Krouse
Keyword(s):  
Root Growth ◽  
Dimethyl Ester ◽  
Growing Season ◽  
Field Studies ◽  
First Year ◽  
Zoysia Japonica ◽  
Second Year ◽  
Herbicide Use ◽  
Preemergence Herbicides ◽  
Postemergence Herbicides

Sprigs of `Meyer' zoysiagrass (Zoysia japonica Steud.) were treated with urea nitrogen, a biostimulator, and one of three preemergence herbicides or one of two postemergence herbicides to hasten establishment in two field studies. Monthly application of N at 48 kg·ha–1 during the growing season had no influence on sprig establishment the first year, but slightly increased (+5%) zoysiagrass cover the second year. Presoaking sprigs in a solution containing (mg·L–1) 173 auxin and 81 cytokinin, and iron at 1.25 g·L–1 before broadcasting of sprigs, and biweekly sprays (g·ha–1) of 53 auxin and 24 cytokinin, and iron at 0.2 g·L–1 or (g·ha–1) 68 auxin and 36 cytokinin, and iron at 1.45 g·L–1 after broadcasting sprigs had no effect on zoysiagrass cover or rooting. Preemergence and postemergence herbicide use generally enhanced zoysiagrass cover by reducing smooth crabgrass competition [Digitaria ischaemum (Schreb. ex Schweig) Schreb. ex Muhl]. Oxadiazon enhanced zoysiagrass coverage more than dithiopyr, pendimethalin, quinclorac, or fenoxaprop. Oxadiazon and dithiopyr provided similar levels of crabgrass control, but dithiopyr reduced `Meyer' zoysiagrass midsummer root growth. Chemical names used: 3,5,-pyridinedicarbothioic acid, 2-[difluromethyl]-4-[2-methyl-propyl]-6-(trifluoromethyl)-S,S-dimethyl ester (dithiopyr); [±]-ethyl 2-[4-[(6-chloro-2-benzoxazolyl)oxy]phenoxy] propanoate (fenoxaprop); 3-[2,4-dichloro-5-(1-methylethoxy)phenyl]-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2-(3H)-one (oxadiazon); N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine (pendimethalin); 3,7-dichloro-8-quin-olinecarboxylic acid (quinclorac).

scholarly journals Seed Coating Technologies and Treatments for Onion: Challenges and Progress

HortScience ◽  
2001 ◽  
Vol 36 (2) ◽  
pp. 199-205 ◽  
Author(s):  
Alan G. Taylor ◽  
C.J. Eckenrode ◽  
R.W. Straub
Keyword(s):  
Root Growth ◽  
Seed Treatment ◽  
Seed Quality ◽  
Field Studies ◽  
Film Coating ◽  
Insect Growth Regulator ◽  
Onion Maggot ◽  
Loading Rates ◽  
Horticultural Crops ◽  
Mammalian Toxicity

Conventional methods to control the onion maggot or onion fly, Delia antiqua (Meigen), have relied on in-furrow applications of the toxicant pesticide, chlorpyrifos. The objective of this research was to develop an onion (Allium cepa L.) seed treatment that utilizes a new chemistry compound that is environmentally safe. Cyromazine is an insect growth regulator with a mode of action different from traditional pesticides used to control onion maggot. Cyromazine has low mammalian toxicity and is relatively nontoxic to other insects, including beneficials. High seed loading rates (50 g·kg-1 active ingredient) are required for optimal efficacy, and conventional slurry methods are inadequate to apply these high loading rates. Film coating and pelleting were performed at Cornell Univ. to apply cyromazine and a registered fungicide (a formulation of thiram and carboxin) to onion seeds. Results of field studies performed over several years revealed that stand losses due to the onion maggot ranged from ≈20% to 60%. Cyromazine applied by either film coating or pelleting decreased the loss by onion maggot from 1% to 8%, and efficacy was comparable to an in-furrow application of chlorpyrifos. Cyromazine was registered as a seed treatment and is commercially used in the northeastern and midwestern United States, where onion maggot is a serious pest. Field emergence was not negatively affected by cyromazine coated onto the seeds when onion seeds are sown in organic (muck) soils. There is other evidence, however, that cyromazine seed treatments may cause phytotoxicity to germination and seedling growth. Testing seed quality in sand or on roll towels revealed a high percentage of abnormal seedlings. Retarded root growth was observed in seeds treated with cyromazine, resulting in an increase in abnormal seedling classifications. A finely ground sphagnum peatmoss applied over the seeds in a roll towel test ameliorated the abnormal root growth symptoms, and seedlings had robust growth. Collectively, film coating and pelleting were effective delivery systems for the application of plant protectants required at time of sowing. Modification of the standard germination test was needed to accurately assess onion seed quality. Moreover, this project was successful due to a team effort of a university seed scientist and entomologists working with onion growers and industry. Future registrations on small acreage, high-value horticultural crops are envisioned to require similar multi-partner approaches. Chemical name used: N-cyclopropyl-1,3,5-triazine-2,4,6-triamine (cyromazine).

scholarly journals A mechanistic model for electrical conduction in soil–root continuum: a virtual rhizotron study

2018 ◽  
Author(s):  
Sathyanarayan Rao ◽  
Félicien Meunier ◽  
Solomon Ehosioke ◽  
Nolwenn Lesparre ◽  
Andreas Kemna ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Root Growth ◽  
Water Content ◽  
Soil Water ◽  
Water Uptake ◽  
Numerical Study ◽  
Root Segments ◽  
Bulk Electrical Conductivity ◽  
The Impact

Abstract. Electrical Resistivity Tomography (ERT) has become an important tool to study soil water fluxes in cropped field. ERT results translates to water content via empirical pedophysical relations that take soil physical properties into account, usually ignoring the impact of roots. Studies shows high root dense soils behaves quite differently than less root dense soils in terms of bulk electrical conductivity. Yet, we do not completely understand the impact of root segments on the ERT measurements. In this numerical study, we coupled an electrical model with a plant-soil water flow model to investigate the impact of plant root growth and water uptake on the ERT virtual experiment. The electrical properties of roots were explicitly accounted in the finite element mesh and we obtained the electrical conductivities of root segments by conducting specific experiments on real maize plants. The contrast between electrical conductivity of roots and soil depends on factors such as root density, irrigation, root age, and root water uptake pattern. Root growth and water uptake processes thus affect this contrast together with the soil electrical properties. Model results indicate a non-negligible anisotropy in bulk electrical conductivity induced by root processes. We see a greater anisotropy in a sandy medium when compared to a loamy medium. We find that the water uptake process dominates the bulk electrical properties. The Gauss-Newton type ERT inversion of virtual rhizotron data demonstrate that, when root-soil electrical conductivity contrasts are high, it can lead to error in water content estimates since the electrical conductivity is partly due to root. Thus, incorporating the impact of root in the pedophysical relations is very important to interpret ERT results directly as water content.

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