The effect of soil temperature and light on sprouting and rooting of root cuttings of hybrid aspen clones

2005 ◽  
Vol 35 (11) ◽  
pp. 2671-2678 ◽  
Author(s):  
N Stenvall ◽  
T Haapala ◽  
S Aarlahti ◽  
P Pulkkinen

Root cuttings from five clones of hybrid aspen (Populus tremula L. × Populus tremuloides Michx.) obtained from 2-year-old stock plants were grown in a peat–sand mixture (soil) at four soil temperatures (18, 22, 26, and 30 °C). Half of the cuttings were grown in light and the rest in darkness. The root cuttings that were grown at the highest soil temperature sprouted and rooted significantly better than the cuttings grown at the lower temperatures. Light did not affect the sprouting of root cuttings but did have a negative effect on their rooting. Moreover, the clones varied significantly in sprouting and rooting percentages, as well as in the time required for sprouting. In general, higher soil temperatures hastened sprouting of the cuttings. Sprouting was also faster in the light than in the dark treatment. Differences in soil temperature, light conditions, or clone had no significant effect on rooting time.

2001 ◽  
pp. 40-44
Author(s):  
Miklós Pakurár ◽  
László Lakatos ◽  
János Nagy

The effect of soil temperature was evaluated on the yield of the Occitan corn hybrid at a depth of 5 cm. We examined this effect on the time required from planting to emergence for three average durations: five, ten and fifteen days, all calculated from the day of planting. Winter plowing (27 cm), spring plowing (23 cm), disc-till (12 cm) treatments and 120 kg N per hectare fertilizer were applied. As a result of our analysis, we determined the post planting optimum soil temperatures for various time periods. The average soil temperature for a time period of 15 days post planting is the most usable for determining actual yields, followed by ten days, with five days proved to be the least usable (winter plow R2 = 0.86, spring plow R2 = 0.87, disc-till R2 = 0.64).


1998 ◽  
Vol 28 (3) ◽  
pp. 396-401 ◽  
Author(s):  
Simon M Landhäusser ◽  
Victor J Lieffers

Three experiments were conducted to examine the effects of Calamagrostis canadensis (Michx.) Beauv. on the growth of Populus tremuloides Michx. Containerized seedlings of P. tremuloides were transplanted into large pots and subjected to (1) three soil temperatures (20, 12, and 6°C), (2) root competition with C. canadensis, or (3) presence or absence of C. canadensis litter, each at two nutrient regimes. In the first experiment, significant differences (p = 0.0001) in pre- and neo-formed leaf area and root and shoot dry weights were observed for plants subjected to the three different soil temperatures. In experiment two, the presence of C. canadensis significantly (p < 0.001) reduced total biomass, plant height, and root collar calliper of P. tremuloides. In the third experiment, a significant interaction (p = 0.027) between C. canadensis litter and nutrient regime was observed, with the greatest inhibitory effect on P. tremuloides growth resulting from litter at the low nutrient regime. Low soil temperature had the strongest negative effect on P. tremuloides of the four factors investigated. However, direct competition with C. canadensis, low nutrient conditions, and C. canadensis litter likely would add to the growth suppression of P. tremuloides by this grass. The results of this study have significant implications for the management of P. tremuloides after harvesting.


2002 ◽  
Vol 80 (6) ◽  
pp. 684-689 ◽  
Author(s):  
Simon M Landhäusser ◽  
Tawfik M Muhsin ◽  
Janusz J Zwiazek

Low soil temperatures, common during the growing season in northern forests, have the potential to impede plant growth. In this study, water uptake, water relations, and growth characteristics were examined in aspen (Populus tremuloides) and white spruce (Picea glauca) seedlings that were inoculated with ectomycorrhizal fungi and grown at 20°C daytime air temperatures and low soil temperatures of 4°C and 8°C. Mycorrhizal associations had little effect on root and shoot biomass at both soil temperatures. Root hydraulic conductance (Kr) was higher in both mycorrhizal plant species compared to nonmycorrhizal plants, but there was no soil temperature effect on Kr in either species. Mycorrhizae also increased shoot water potential (Ψw) in Populus tremuloides but had no effect on Ψw in Picea glauca. The increases in Kr and Ψw were not reflected by changes in stomatal conductance (gs) and transpiration rates (E), suggesting that the reduction of water flow in seedlings exposed to low soil temperature was not likely the factor limiting gs in both plant species.Key words: boreal forest, root hydraulic conductance, root growth, stomatal conductance, water uptake.


2004 ◽  
Vol 80 (6) ◽  
pp. 687-693 ◽  
Author(s):  
Timothy Conlin ◽  
Dave Cheyne ◽  
John Dymond

Bark and wood residue, commonly referred to as "hog fuel" or "hog," from a portable pulp chipper was deposited on aspen cutblocks in replicated 10 x 10 m treatment plots during winter logging operations in northeastern British Columbia. The treatments emulated disposal of hog under conditions that simulated on-site chipping operations. Three different rates of hog disposal were applied; 34, 68 and 102 kg m-2, and three cutblocks were treated, one each during February of 1997, and March of 1998 and 1999. We originally hypothesized that the deposition of hog would lower soil temperatures in the treated plots and reduce aspen sucker density during the following growing season. However, our observations showed an initial lag in soil warming in the treatments followed by temperature levels that rose above that exhibited in the control plots. Higher soil temperatures were correlated with greater rates of hog disposal. Increased suckering was not observed in response to higher soil temperatures and stem densities decreased as hog application rates increased. Key words: in-woods, on-site, chipping, Populus tremuloides, hog fuel, soil temperature


1995 ◽  
Vol 13 (2) ◽  
pp. 77-81
Author(s):  
Norman E. Pellett ◽  
David A. Heleba

Abstract Chopped newspaper was evaluated as a weed control mulch for nursery row crops. Newspaper mulch at 2.3 and 3.6 kg/m2 [4.2 lb/yd2 (≈ 10 cm or 4 in depth) and 6.3 lb/yd2 (≈ 15 cm or 6 in depth), resp.] suppressed weed germination for two seasons without a negative effect on Daphne burkwoodii ‘Carol Mackie’, Physostegia virginiana, and Salix caprea. Gaillardia grandiflora had less growth when mulched with newspaper during one experiment, but not in another. The authors observed that wetting the newspaper mulch after application followed by compression with a lawn roller pressed the paper into a mat which resisted blowing and weathering. Further reduction in blowing of paper mulch was achieved by applying a tackifier after rolling. Bark mulch at 19.4 dm3/m2 (988 in3/yd2 ≈ 10 cm or 4 in depth) resulted in weed suppression comparable to either of the two rates of newspaper mulch and better than bark at 9.7 dm3/m2 (494 in3/yd2 ≈ 5 cm or 2 in depth). All mulch treatments moderated maximum soil temperatures on July 5, 1993 at 7.5 cm (3 in) depth by more than 10C (18F) when non-mulched soil increased to 36C (96.8F). The rate or type of mulch applied resulted in similar summer soil temperatures at 2.5 and 7.5 cm (1 and 3 in) soil depth.


1978 ◽  
Vol 56 (15) ◽  
pp. 1782-1791 ◽  
Author(s):  
D. W. Smith ◽  
T. D. James

In a series of prescribed burns of low intensity and short duration in southern Ontario, wind speed, amount of fuel, and fuel moisture were important environmental controls of fire severity. A heterogenous pattern of burning, related to clumping in the vegetation and to a hummock–hollow microtopography presumably affected and was perpetuated in the reestablishing postfire vegetation.Removal of vegetation cover and surface litter plus surface albedo changes resulted in increased soil temperature 2 months after burning. These increases were short-lived and soil temperatures were close to those of unburned areas 4 months after the prescribed fires. Despite their small magnitude and short duration, the soil temperature increases could have an important stimulatory effect on regenerating vegetation.Significant increases in levels of readily available forms of phosphorus, potassium, calcium, and magnesium at surface soil depths immediately after burning could have been depleted through uptake by vegetation and microorganisms. Portions of the nutrients were removed, also, by erosion of fly ash during burning, leaching to subsurface depths, and through fixation in unavailable form.


2005 ◽  
Vol 44 (12) ◽  
pp. 1827-1843 ◽  
Author(s):  
Balachandrudu Narapusetty ◽  
Nicole Mölders

Abstract The Hydro–Thermodynamic Soil–Vegetation Scheme (HTSVS) coupled in a two-way mode with the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (NCAR) Mesoscale Meteorological Model (MM5) is evaluated for a typical snowmelt episode in the Baltic region by means of observations at 25 soil temperature, 355 snow-depth, and 344 precipitation sites that have, in total, 1000, 1775, and 1720 measurements, respectively. The performance with respect to predicted near-surface meteorological fields is evaluated using reanalysis data. Snow depth depends on snow metamorphism, sublimation, and snowfall. Because in the coupled model these processes are affected by the predicted surface radiation fluxes and cloud and precipitation processes, sensitivity studies are performed with two different cloud microphysical schemes and/or radiation schemes. Skill scores are calculated as a quality measure for the coupled model’s performance for a typical forecast range of 120 h for a typical spring (snowmelt) weather situation in the Baltic region. Discrepancies between predicted and observed snow-depth changes relate to the coupling. Enhanced water supply to the atmosphere, which results from water that was assumed to be open in MM5 but was actually ice covered in nature, finally leads to an overestimation of snowfall (input to HTSVS) and changes in snow depth (output). The resolution-dependent discrepancies between the terrain height in the model and real world also lead to snowfall where none occurred. For heavy snowfall the performance of the coupled model with respect to predicted snow-depth changes becomes nearly independent of the choice of the cloud microphysical and radiation schemes. As compared with observed changes in snow depth, the coupled model simulation using the Schultz scheme in conjunction with the radiation scheme from the Community Climate Model, version 2, (CCM2) predicts snow-depth changes of less than 2.5 mm considerably better than the other combinations that were tested. For thick snowpacks, the accuracy of the snow-depth decrease resulting from metamorphism strongly depends on the initial value of snow density. The coupled model acceptably captures the soil temperature diurnal cycles, the observed soil temperature increase with time, and the soil temperature behavior with depth. In general, discrepancies between simulated and observed soil temperatures decrease with soil depth. Simulations performed with the so-called CLOUD radiation scheme capture soil temperature minima and maxima better than do simulations performed with the CCM2 scheme.


Atmosphere ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 441
Author(s):  
Philipp Grabenweger ◽  
Branislava Lalic ◽  
Miroslav Trnka ◽  
Jan Balek ◽  
Erwin Murer ◽  
...  

A one-dimensional simulation model that simulates daily mean soil temperature on a daily time-step basis, named AGRISOTES (AGRIcultural SOil TEmperature Simulation), is described. It considers ground coverage by biomass or a snow layer and accounts for the freeze/thaw effect of soil water. The model is designed for use on agricultural land with limited (and mostly easily available) input data, for estimating soil temperature spatial patterns, for single sites (as a stand-alone version), or in context with agrometeorological and agronomic models. The calibration and validation of the model are carried out on measured soil temperatures in experimental fields and other measurement sites with various climates, agricultural land uses and soil conditions in Europe. The model validation shows good results, but they are determined strongly by the quality and representativeness of the measured or estimated input parameters to which the model is most sensitive, particularly soil cover dynamics (biomass and snow cover), soil pore volume, soil texture and water content over the soil column.


Author(s):  
Sankirti Sandeep Shiravale ◽  
R. Jayadevan ◽  
Sanjeev S. Sannakki

Text present in a camera captured scene images is semantically rich and can be used for image understanding. Automatic detection, extraction, and recognition of text are crucial in image understanding applications. Text detection from natural scene images is a tedious task due to complex background, uneven light conditions, multi-coloured and multi-sized font. Two techniques, namely ‘edge detection' and ‘colour-based clustering', are combined in this paper to detect text in scene images. Region properties are used for elimination of falsely generated annotations. A dataset of 1250 images is created and used for experimentation. Experimental results show that the combined approach performs better than the individual approaches.


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