Effect of Wild Oat (Avena fatua) Infestations on Light Interception and Growth Rate of Wheat (Triticum aestivum)

Weed Science ◽  
1991 ◽  
Vol 39 (2) ◽  
pp. 175-179 ◽  
Author(s):  
David W. Cudney ◽  
Lowell S. Jordan ◽  
Anthony E. Hall
Keyword(s):  
Growth Rate ◽  
Field Experiments ◽  
Early Growth ◽  
Growth Stages ◽  
Wild Oat ◽  
Light Penetration ◽  
Hard Red Spring Wheat ◽  
Wheat Leaves ◽  
Moisture Conditions ◽  
Reduced Light

Wild oat reduced light penetration and growth of dwarf hard red spring wheat in field experiments performed under nonlimiting nitrogen and moisture conditions. Wild oat grew taller than wheat and had a greater portion of its canopy above 60 cm at maturity. Light penetration in a mixed canopy was similar to that in a monoculture wheat canopy when wild oat was clipped to the height of the wheat. A mathematical model was developed which accurately predicted the reduction in the growth rate of wheat from wild oat interference. The model also predicted that interference from wild oat was due to reduced leaf area of wheat at early growth stages and low wild oat densities, and reduced light penetration to wheat leaves at later growth stages and higher densities of wild oat.

Effect of Application Factors on Efficacy of Fluazifop-P-Butyl in Flax

1991 ◽  
Vol 5 (3) ◽  
pp. 504-508 ◽  
Author(s):  
George H. Friesen ◽  
David A. Wall
Keyword(s):  
Growth Stage ◽  
Field Experiments ◽  
Time Of Day ◽  
Wild Oat ◽  
Spray Nozzle ◽  
Green Foxtail ◽  
Drought Conditions ◽  
Orientation Time ◽  
Moisture Conditions ◽  
Nozzle Orientation

Field experiments were conducted to determine the efficacy of fluazifop-P-butyl for the control of green foxtail, wild oat, barley, and wheat in flax as influenced by spray nozzle orientation, time of day, and growth stage. Under drought conditions in 1988, control of wild oat, wheat, and barley with fluazifop-P-butyl was enhanced 75%, 53% and 78%, respectively, when nozzles were oriented to spray forward 45°. Under adequate soil moisture conditions enhancement of control was minimal. Green foxtail control improved when fluazifop-P-butyl was applied from 1700 to 2100 h, but time of day had no effect on control of wild oat, barley, or wheat. Fluazifop-P-butyl effectiveness was reduced when applied 4 d after flax emergence due to late emerging grass seedlings. Green foxtail was the most tolerant to fluazifop-P-butyl, whereas wild oat, wheat, and barley were the most susceptible.

Effect of imazamethabenz on green foxtail, tartary buckwheat and wild oat at different growth stages

1991 ◽  
Vol 71 (3) ◽  
pp. 821-829 ◽  
Author(s):  
K. N. Harker ◽  
P. A. O'Sullivan
Keyword(s):  
Growth Stage ◽  
Field Experiments ◽  
Avena Fatua ◽  
Tartary Buckwheat ◽  
Growth Stages ◽  
Research Station ◽  
Regression Equations ◽  
Wild Oat ◽  
Setaria Viridis ◽  
Green Foxtail

Field experiments were conducted at the Lacombe Research Station to determine the influence of growth stage on the control of wild oat (Avena fatua L.) and Tartary buckwheat (Fagopyrum tartaricum (L.) Gaertn.) with imazamethabenz in wheat (Triticum aestivum L.). In greenhouse experiments, the effct of imazamethabenz on canola (Brassica campestris L.) or green foxtail (Setaria viridis L. Beauv.) at two growth stages was also studied. Canola and wild oat were highly susceptible, Tartary buckwheat was somewhat less susceptible, and green foxtail was rather tolerant to imazamethabenz. Imazamethabenz was much more effective on early growth stages of wild oat (2 leaf) and Tartary buckwheat (1–2 leaf), whereas the control of canola and the suppression of green foxtail was much less dependent on growth stage. Linear regression equations were developed to describe the response of the above species to the imazamethabenz treatments. Key words: AC 222, 293; phenology; regression; Setaria viridis; Fagopyrum tartaricum; Avena fatua

Importance of tolerance and growth rate in the resistance of oilseed rapes and mustards to flea beetles, Phyllotreta cruciferae (Goeze) (Coleoptera: Chrysomelidae)

1994 ◽  
Vol 74 (1) ◽  
pp. 169-176 ◽  
Author(s):  
R. N. Brandt ◽  
R. J. Lamb
Keyword(s):  
Growth Rate ◽  
Brassica Juncea ◽  
Brassica Rapa ◽  
Flea Beetle ◽  
Early Growth ◽  
Growth Stages ◽  
Feeding Damage ◽  
Brassica Napus L ◽  
Phyllotreta Cruciferae ◽  
Flea Beetles

The resistance of oilseed rapes and mustards to crucifer flea beetles, Phyllotreta cruciferae (Goeze), is known to vary, and tolerance to feeding damage may be a factor in the resistance shown by two of the species. The tolerance of Brassica juncea L., Brassica napus L., Brassica rapa L. and Sinapis alba L. was compared in field and laboratory studies. The growth rates of damaged and undamaged plants were measured at four early growth stages, and the level of antixenosis was determined to ascertain the relative importance of tolerance and antixenosis and the relationship between tolerance and growth rate. Antixenosis was confirmed to be a factor in the resistance of S. alba, but this species also proved to be most tolerant of feeding damage and showed rapid compensatory growth at three early growth stages. Brassica juncea showed no antixenosis, but it was tolerant of damage particularly at germination, the cotyledon stage, and the first true leaf stages, which probably accounts for its resistance to moderate flea beetle damage. Brassica rapa showed only a very low level of tolerance, and B. napus was intolerant of damage at all four growth stages. The level of tolerance was species specific and growth-stage specific and was not related to the rates of growth of the species. Key words: Insecta, antixenosis, canola, crucifer flea beetles

scholarly journals Improvement of the Soil Moisture Retrieval Procedure Based on the Integration of UAV Photogrammetry and Satellite Remote Sensing Information

2021 ◽  
Vol 13 (24) ◽  
pp. 4968
Author(s):  
Amal Chakhar ◽  
David Hernández-López ◽  
Rocío Ballesteros ◽  
Miguel A. Moreno
Keyword(s):  
Soil Moisture ◽  
Bare Soil ◽  
Arid Environment ◽  
Early Growth ◽  
Precise Determination ◽  
Growth Stages ◽  
Crop Fields ◽  
Moisture Conditions ◽  
Semi Arid ◽  
Cultivated Soils

In countries characterized by arid and semi-arid climates, a precise determination of soil moisture conditions on the field scale is critically important, especially in the first crop growth stages, to schedule irrigation and to avoid wasting water. The objective of this study was to apply the operative methodology that allowed surface soil moisture (SSM) content in a semi-arid environment to be estimated. SSM retrieval was carried out by combining two scattering models (IEM and WCM), supplied by backscattering coefficients at the VV polarization obtained from the C-band Synthetic Aperture Radar (SAR), a vegetation descriptor NDVI obtained from the optical sensor, among other essential parameters. The inversion of these models was performed by Neural Networks (NN). The combined models were calibrated by the Sentinel 1 and Sentinel 2 data collected on bare soil, and in cereal, pea and onion crop fields. To retrieve SSM, these scattering models need accurate measurements of the roughness surface parameters, standard deviation of the surface height (hrms) and correlation length (L). This work used a photogrammetric acquisition system carried on Unmanned Aerial Vehicles (UAV) to reconstruct digital surface models (DSM), which allowed these soil roughness parameters to be acquired in a large portion of the studied fields. The obtained results showed that the applied improved methodology effectively estimated SSM on bare and cultivated soils in the principal early growth stages. The bare soil experimentation yielded an R2 = 0.74 between the estimated and observed SSMs. For the cereal field, the relation between the estimated and measured SSMs yielded R2 = 0.71. In the experimental pea fields, the relation between the estimated and measured SSMs revealed R2 = 0.72 and 0.78, respectively, for peas 1 and peas 2. For the onion experimentation, the highest R2 equaled 0.5 in the principal growth stage (leaf development), but the crop R2 drastically decreased to 0.08 in the completed growth phase. The acquired results showed that the applied improved methodology proves to be an effective tool for estimating the SSM on bare and cultivated soils in the principal early growth stages.

scholarly journals Osmotic Stress or Ionic Composition: Which Affects the Early Growth of Crop Species More?

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 435
Author(s):  
Agnieszka Ludwiczak ◽  
Monika Osiak ◽  
Stefany Cárdenas-Pérez ◽  
Sandra Lubińska-Mielińska ◽  
Agnieszka Piernik
Keyword(s):  
Osmotic Stress ◽  
Stress Responses ◽  
Ionic Composition ◽  
Degradation Process ◽  
Early Growth ◽  
Cultivated Plants ◽  
C3 Plants ◽  
Growth Stages ◽  
Crop Species ◽  
Ionic Salt

Salinization is a key soil degradation process. An estimated 20% of total cultivated lands and 33% of irrigated agricultural lands worldwide are affected by high salinity. Much research has investigated the influence of salt (mainly NaCl) on plants, but very little is known about how this is related to natural salinity and osmotic stress. Therefore, our study was conducted to determine the osmotic and ionic salt stress responses of selected C3 and C4 cultivated plants. We focused on the early growth stages as those critical for plant development. We applied natural brine to simulate natural salinity and to compare its effect to NaCl solution. We assessed traits related to germination ability, seedlings and plantlet morphology, growth indexes, and biomass and water accumulation. Our results demonstrate that the effects of salinity on growth are strongest among plantlets. Salinity most affected water absorption in C3 plants (28% of total traits variation), but plant length in C4 plants (17–27%). Compensatory effect of ions from brine were suggested by the higher model plants’ growth success of ca 5–7% under brine compared to the NaCl condition. However, trait differences indicated that osmotic stress was the main stress factor affecting the studied plants.

scholarly journals Vegetation Response to Goats Grazing Intensity in Semiarid Hilly Grassland of the Loess Plateau, Lanzhou, China

2021 ◽  
Vol 13 (6) ◽  
pp. 3569
Author(s):  
Hua Cheng ◽  
Baocheng Jin ◽  
Kai Luo ◽  
Jiuying Pei ◽  
Xueli Zhang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Community Structure ◽  
Plant Growth ◽  
Loess Plateau ◽  
Grazing Intensity ◽  
Gps Tracking ◽  
Growth Stages ◽  
The Loess Plateau ◽  
Vegetation Community ◽  
Natural Grasslands

Quantitatively estimating the grazing intensity (GI) effects on vegetation in semiarid hilly grassland of the Loess Plateau can help to develop safe utilization levels for natural grasslands, which is a necessity of maintaining livestock production and sustainable development of grasslands. Normalized difference vegetation index (NDVI), field vegetation data, and 181 days (one goat per day) of GPS tracking were combined to quantify the spatial pattern of GI, and its effects on the vegetation community structure. The spatial distribution of GI was uneven, with a mean value of 0.50 goats/ha, and 95% of the study area had less than 1.30 goats/ha. The areas with utilization rates of rangeland (July) lower than 45% and 20% made up about 95% and 60% of the study area, respectively. Grazing significantly reduced monthly aboveground biomass, but the grazing effects on plant growth rate were complex across the different plant growth stages. Grazing impaired plant growth in general, but the intermediate GI appeared to facilitate plant growth rate at the end of the growing seasons. Grazing had minimal relationship with vegetation community structure characteristics, though Importance Value of forbs increased with increasing GI. Flexibility in the number of goats and conservatively defining utilization rate, according to the inter-annual variation of utilization biomass, would be beneficial to achieve ecologically healthy and economically sustainable GI.

scholarly journals Coastal Mangrove Response to Marine Erosion: Evaluating the Impacts of Spatial Distribution and Vegetation Growth in Bangkok Bay from 1987 to 2017

2020 ◽  
Vol 12 (2) ◽  
pp. 220 ◽  
Author(s):  
Han Xiao ◽  
Fenzhen Su ◽  
Dongjie Fu ◽  
Qi Wang ◽  
Chong Huang
Keyword(s):  
Spatial Distribution ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Mangrove Ecosystem ◽  
Early Growth ◽  
Growth Stages ◽  
Human Disturbances ◽  
Vegetation Growth ◽  
Two Parameters ◽  
The Impact

Long time-series monitoring of mangroves to marine erosion in the Bay of Bangkok, using Landsat data from 1987 to 2017, shows responses including landward retreat and seaward extension. Quantitative assessment of these responses with respect to spatial distribution and vegetation growth shows differing relationships depending on mangrove growth stage. Using transects perpendicular to the shoreline, we calculated the cross-shore mangrove extent (width) to represent spatial distribution, and the normalized difference vegetation index (NDVI) was used to represent vegetation growth. Correlations were then compared between mangrove seaside changes and the two parameters—mangrove width and NDVI—at yearly and 10-year scales. Both spatial distribution and vegetation growth display positive impacts on mangrove ecosystem stability: At early growth stages, mangrove stability is positively related to spatial distribution, whereas at mature growth the impact of vegetation growth is greater. Thus, we conclude that at early growth stages, planting width and area are more critical for stability, whereas for mature mangroves, management activities should focus on sustaining vegetation health and density. This study provides new rapid insights into monitoring and managing mangroves, based on analyses of parameters from historical satellite-derived information, which succinctly capture the net effect of complex environmental and human disturbances.

scholarly journals Effect of sodium silicate on early growth stages of wheat under drought stress

2020 ◽  
Vol 63 (1) ◽  
Author(s):  
Sang Gyu Lee ◽  
Hyeri Lee ◽  
Byung Cheon Lee ◽  
Hojoung Lee ◽  
Jun Cheol Moon ◽  
...  
Keyword(s):  
Drought Stress ◽  
Sodium Silicate ◽  
Early Growth ◽  
Growth Stages

scholarly journals Physiological and ecological consequences of the water optical properties degradation on reef corals

Coral Reefs ◽  
2021 ◽  
Author(s):  
Tomás López-Londoño ◽  
Claudia T. Galindo-Martínez ◽  
Kelly Gómez-Campo ◽  
Luis A. González-Guerrero ◽  
Sofia Roitman ◽  
...  
Keyword(s):  
Optical Properties ◽  
Population Decline ◽  
Light Availability ◽  
Potential Effect ◽  
Optical Quality ◽  
Light Penetration ◽  
Reef Corals ◽  
Orbicella Faveolata ◽  
Light Quantity ◽  
Reduced Light

AbstractDegradation of water optical properties due to anthropogenic disturbances is a common phenomenon in coastal waters globally. Although this condition is associated with multiple drivers that affect corals health in multiple ways, its effect on light availability and photosynthetic energy acquisition has been largely neglected. Here, we describe how declining the water optical quality in a coastal reef exposed to a turbid plume of water originating from a man-made channel compromises the functionality of the keystone coral species Orbicella faveolata. We found highly variable water optical conditions with significant effects on the light quantity and quality available for corals. Low-light phenotypes close to theoretical limits of photoacclimation were found at shallow depths as a result of reduced light penetration. The estimated photosynthetically fixed energy depletion with increasing depth was associated with patterns of colony mortality and vertical habitat compression. A numerical model illustrates the potential effect of the progressive water quality degradation on coral mortality and population decline along the depth gradient. Collectively, our findings suggest that preserving the water properties seeking to maximize light penetration through the water column is essential for maintaining the coral reef structure and associated ecosystem services.

scholarly journals The Columbian Restriction Gene, Co, and Early Growth Rate in the Domestic Fowl

1984 ◽  
Vol 63 (3) ◽  
pp. 586-588
Author(s):  
THOMAS W. FOX ◽  
J. ROBERT SMYTH
Keyword(s):  
Growth Rate ◽  
Domestic Fowl ◽  
Early Growth
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