Integration of soil moisture, xylem water potential, and fall–spring herbicide treatments to achieve the maximum growth response in newly planted Douglas-fir seedlings

2009 ◽  
Vol 39 (7) ◽  
pp. 1401-1414 ◽  
Author(s):  
Eric J. Dinger ◽  
Robin Rose
Keyword(s):  
Soil Moisture ◽  
Water Potential ◽  
Seedling Growth ◽  
Growth Response ◽  
Volume Growth ◽  
Maximum Growth ◽  
Douglas Fir ◽  
Xylem Water Potential ◽  
Treatment Regimes ◽  
Herbicide Treatment

Early in the establishment of Pacific Northwest Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) plantations, herbaceous vegetation can decrease seedling growth through competition for soil moisture during the dry summer months. This study was designed to statistically quantify soil moisture, seedling xylem water potential (Ψ), vegetation community, and seedling growth response to six herbicide treatment regimes commonly applied over the first 2 years of establishment. When compared with the control, soil moisture and seedling Ψ increased in response to reductions in competitive cover, allowing seedlings to extend productive growing time from 28 to 80 days. As a result, seedling volume growth increased from 56 cm3 in the untreated control to greater than 250 cm3 for the most intensive herbicide treatment regimes. Vegetation surveys revealed that treatment regimes had the potential to provide a disturbance, which could shift community composition from native to introduced species as the relationship decreased from 10:1 to 2:1. The most intense herbicide treatment regime reduced cover below 20%, retained soil moisture >30%, maintained predawn seedling Ψ above –1.0 MPa, and decreased height to diameter ratio below 50, increasing the likelihood of successful plantation establishment.

Growth Response to Fertilization in Young Douglas-Fir Stands

1989 ◽  
Vol 4 (4) ◽  
pp. 116-119 ◽  
Author(s):  
Linda S. Heath ◽  
H. N. Chappell
Keyword(s):  
Pseudotsuga Menziesii ◽  
Growth Response ◽  
Volume Growth ◽  
Basal Area ◽  
Site Index ◽  
Douglas Fir ◽  
Intermediate Region ◽  
Fertilizer Response ◽  
Breast Height ◽  
Inverse Effect

Abstract Response surface methodology was used to estimate six-year volume growth response to 1 application of 200 lb nitrogen per acre in unthinned and thinned Douglas-fir (Pseudotsuga menziesii) stands of breast height age (bha) 25 years or less. Regional mean fertilizer response was 16% in unthinned stands and 20% in thinned stands. Site index had an increasingly inverse effect on response as basal area increased in both unthinned and thinned stands. Response varied little over site index in regions of low basal area, decreased moderately as site index increased in the intermediate region, and decreased rapidly in the high basal area region. West. J. Appl. For. 4(4):116-119, October 1989.

Response of coastal Douglas-fir and competing vegetation to repeated and delayed weed control treatments during early plantation development

2009 ◽  
Vol 39 (6) ◽  
pp. 1208-1219 ◽  
Author(s):  
Douglas A. Maguire ◽  
Douglas B. Mainwaring ◽  
Robin Rose ◽  
Sean M. Garber ◽  
Eric J. Dinger
Keyword(s):  
Weed Control ◽  
Seedling Growth ◽  
Volume Growth ◽  
Douglas Fir ◽  
Optimal Regime ◽  
Competitive Effects ◽  
Competing Vegetation ◽  
Plantation Development ◽  
Age Shift

A key silvicultural decision in managing young conifer plantations is determining the number and timing of release treatments to control competing vegetation. Three coastal Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) plantations were treated under eight alternative herbicide regimes during the first 5 years after planting to test treatment effects on vegetation dynamics and seedling growth. After termination of herbicide treatments, competing vegetation developed at a rate similar to that of check plots, reaching 40%–60% cover in the first growing season and approaching 100% by the third. Recovery of competing vegetation was slightly more rapid with greater number of previous releases. Annual volume growth of seedlings was negatively correlated with current cover of competing vegetation, but competitive effects from previous years were fully accounted for by initial tree size. Under 4 years of release, delaying treatment by 1 year reduced volume attained at the end of 5 years by about 15%. Plots receiving 5 consecutive years of weed control reached the 5 year volume of check plots in only 3.9 years, implying an age shift of 1.1 years. Increasing the number of operational release treatments significantly improved seedling growth in the short term, but long-term growth effects must be monitored to determine the economically optimal regime.

scholarly journals Water Stress Patterns of Xerophytic Plants in an Urban Landscape

HortScience ◽  
2019 ◽  
Vol 54 (5) ◽  
pp. 818-823 ◽  
Author(s):  
Richard Martinson ◽  
John Lambrinos ◽  
Ricardo Mata-González
Keyword(s):  
Soil Moisture ◽  
Water Potential ◽  
Water Use ◽  
Management Practices ◽  
Urban Landscape ◽  
Water Status ◽  
Arid Environment ◽  
Irrigation Scheduling ◽  
Urban Landscapes ◽  
Xylem Water Potential

Efficient water use in urban landscapes is a common objective throughout the western United States. Vegetative species promoted for their drought tolerance characteristics are often included in landscapes designed for resource conservation. However, water requirements of most common landscape species have not been quantified. This is especially true for xerophytic species. This lack of landscape plant water requirement data is a significant constraint on the design of efficient irrigation systems and management practices affecting urban landscape water use. Current irrigation practices often fail to consider the unique physiology of xerophytic species, and irrigation scheduling models may not be appropriate for xeric landscapes using xerophytic vegetation as the primary method of reducing water use. This work describes the seasonal patterns of growth and xylem water status for four regionally native xeric shrub species planted in an unirrigated urban landscape in the semi-arid environment of central Oregon. The four species (Artemisia tridentata, Holodiscus microphyllus, Ericameria nauseosa, and Ribes cereum) exhibited substantial growth over the course of 18 months without irrigation in a heavily modified urban soil profile. Water potential of the four species was strongly correlated with surface (10 cm) soil moisture (r ≥ 0.90), less so with reference monthly evapotranspiration (r ≤ 0.55), and only weakly with water vapor deficit (r ≤ 0.22). In A. tridentata and H. microphyllus, xylem water potential became more negative during the growing season and tracked the seasonal decline in soil moisture. In contrast, the xylem water potential of E. nauseosa and R. cereum tracked soil moisture early in the season but became less responsive to soil moisture in the driest months, suggesting different drought adaptation strategies in these species. Three of the four species showed no visual signs of drought stress and maintained acceptable aesthetics even as soil moisture decreased to less than 10%. However, R. cereum exhibited a drought dormancy strategy that made it less aesthetically desirable. These results suggest that extreme xerophytic shrubs provide an opportunity for significant reductions in water use in urban landscapes.

Growth response of unthinned and thinned Douglas-fir stands to single and multiple applications of nitrogen

1990 ◽  
Vol 20 (3) ◽  
pp. 343-349 ◽  
Author(s):  
K. A. Stegemoeller ◽  
H. N. Chappell
Keyword(s):  
Growth Response ◽  
Regional Scale ◽  
Volume Growth ◽  
Basal Area ◽  
Douglas Fir ◽  
Untreated Plot ◽  
Growth Responses ◽  
Average Growth ◽  
Duration Of Response ◽  
And Control

Basal area and volume growth response of unthinned and thinned Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands to single and multiple applications of nitrogen fertilizer were estimated for eight 2-year periods. Response estimates, as differences between growth rates on fertilized and control plots after adjusting for initial volume (or basal area), and trends were analyzed on a regional scale. Average responses to the initial fertilization and to both the second and third fertilizer applications, 8 and 12 years later, were statistically significant (p < 0.05). In thinned stands, average duration of response to the initial treatment was approximately 8 years; unthinned stands continued to show significant volume growth response through 14 years, although basal area growth response decreased to nonsignificant levels between years 10 and 12. In both cases, the response to refertilization, while significant, was smaller than the response to the initial fertilization. Nitrogen applied after the 8th year, and a refertilization after the 12th, on one initially untreated plot at each installation also produced significant average growth responses.

Estimation of twig xylem water potential in young Douglas-fir trees

1984 ◽  
Vol 14 (4) ◽  
pp. 481-487 ◽  
Author(s):  
F. M. Kelliher ◽  
T. A. Black ◽  
A. G. Barr
Keyword(s):  
Water Potential ◽  
Root Zone ◽  
Water Pressure ◽  
Soil Water Potential ◽  
Douglas Fir ◽  
Logarithmic Function ◽  
Pressure Potential ◽  
Xylem Water Potential ◽  
The Difference ◽  
Chamber Measurements

Methodology, based on water flow theory, is described which can be used to estimate twig xylem water potential for 10–15 m tall Douglas-fir (Pseudotsugamenziesii) (Mirb.) Franco) trees. Using pressure chamber measurements, values of needle xylem water pressure potential were found to be similar to twig xylem water pressure potential. For root zone soil water potential (ψs) > −0.4 MPa, measured predawn total twig xylem water potential (ψTtx) of these Douglas-fir trees was significantly less than ψs. A transpiration rate (E) dependent single soil to twig liquid resistance (Rst) accounted for the difference between predawn ψTtx and ψs. For ψs > −0.4 MPa, during the daytime when E was high, Rst could be described by a logarithmic function of ψs. The effect of capacitance on twig xylem water potential (ψtx) was small. A model incorporating the transpiration dependent Rst accurately estimated the course of ψtx on a clear day when ψs was −0.04 MPa.

The contribution of the gibberellin-insensitive semi-dwarfing (Rht) genes to genetic variation in wheat seedling growth in response to osmotic stress

2007 ◽  
Vol 146 (3) ◽  
pp. 275-286 ◽  
Author(s):  
S. LANDJEVA ◽  
V. KORZUN ◽  
E. STOIMENOVA ◽  
B. TRUBERG ◽  
G. GANEVA ◽  
...  
Keyword(s):  
Water Potential ◽  
Seedling Growth ◽  
Growth Response ◽  
Wheat Seedling ◽  
Tolerance Index ◽  
Growth Responses ◽  
Wheat Seedlings ◽  
Allelic Status ◽  
Peg Treatment ◽  
Low Water Potential

SUMMARYThe effects of various gibberellin-insensitive semi-dwarfing (Rht) alleles and background genotypes on the growth response of wheat seedlings to simulated low water potential were investigated. Four sets of near-isogenic lines, each consisting of six members (Rht-B1a+Rht-D1a (rht), Rht-B1b, Rht-B1c, Rht-D1b, Rht-B1b+Rht-D1b and Rht-B1c+Rht-D1b), and one set of five members (rht, Rht-B1b, Rht-B1c, Rht-B1d and Rht-D1b) were germinated in the presence of polyethylene glycol (PEG). The growth responses were assessed by measuring the lengths of the longest root, coleoptile and longest leaf (shoot) and calculating the root length:shoot length ratio and a tolerance index (TI). Seedling growth was significantly affected by the allelic status at the Rht loci, background genes and the water potential. The PEG treatment had major effects on root and shoot growth. Coleoptile growth was mainly affected by the Rht alleles. There were significant interactions of the Rht allele and variety on the growth response to low water potential. Genotypes with longer roots, coleoptiles and shoots when grown in water, as determined by the Rht allelic status (rht, Rht-B1b and Rht-D1b) and varietal background, had the highest TI and maintained this advantage under stress, while genotypes with smaller seedlings (Rht-B1c and Rht-B1c+Rht-D1b) when grown in water were more strongly affected.

scholarly journals A Comparison of Herbicide and Mulch Mat Treatments for Reducing Grass, Herb, and Shrub Competition in the BC Interior Douglas-Fir Zone—Ten-Year Results

2005 ◽  
Vol 20 (3) ◽  
pp. 167-176 ◽  
Author(s):  
G. J. Harper ◽  
P. G. Comeau ◽  
B. S. Biring
Keyword(s):  
Soil Moisture ◽  
Seedling Growth ◽  
Height Growth ◽  
Douglas Fir ◽  
Effective Control ◽  
Soil Drought ◽  
Plastic Mulch ◽  
Growth And Survival ◽  
Growing Seasons ◽  
Soil Moisture Availability

Abstract We present results from a study established in 1993 in the Interior Douglas-fir biogeoclimatic zone of southwestern British Columbia to test the effectiveness of several herbicide and mulch mat treatments for reducing grass, herbaceous, and shrub competition. The effectiveness of the preplant herbicide applications of hexazinone (Velpar L) at 2.1 kg ai/ha, glyphosate (Vision) at 2.1 and 1.0 kg ai/ha, and the installation of plastic mulch mats (Tredegar 90 × 90-cm mats) for controlling competing vegetation, improving seedling growth and survival of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings and improving soil moisture availability was evaluated. Ten-year results indicate that application of hexazinone and glyphosate enhanced the survival, diameter, and height growth of planted Douglas-fir seedlings. These herbicide treatments provided effective control of grass and herbaceous vegetation for three to four growing seasons. Plastic mulch mats did result in improvements in growth and survival, but these were not statistically different from untreated seedlings. The results of soil moisture monitoring from within the various treatments indicated delay in the onset of soil drought as a key determinant of the seedling growth improvement noted. West. J. Appl. For. 20(3):167–176.

scholarly journals Physiologic parameters of soybean of determinate and indeterminate growth habit subjected to levels of soil moisture

2017 ◽  
Vol 52 (6) ◽  
pp. 419-425 ◽  
Author(s):  
Carlos Sebastião Machado Júnior ◽  
Cláudio Ricardo da Silva ◽  
Maria Cristina Sanches ◽  
Osvaldo Toshiyuki Hamawaki ◽  
Larissa Barbosa de Sousa
Keyword(s):  
Soil Moisture ◽  
Grain Yield ◽  
Water Potential ◽  
Dry Matter ◽  
Growth Habit ◽  
Control Level ◽  
Xylem Water Potential ◽  
Indeterminate Growth ◽  
Indeterminate Growth Habit ◽  
Growth Habits

Abstract: The objective of this work was to evaluate the physiological and production parameters of soybean (Glycine max) cultivars of determinate and indeterminate growth habits, in three levels of soil moisture. Three cultivars of determinate growth habit and three of indeterminate growth, at the beginning of the reproductive stage, were subjected to three levels of soil moisture: control, moisture at field capacity; moderated, 50% of the control level; and severe, 25% of the control level. Leaf gas exchange, xylem-water potential, chlorophyll content, chlorophyll a fluorescence, plant dry matter, and grain yield per plant were evaluated. The cultivars of indeterminate growth habit showed the greatest values for stomatal conductance and CO2 assimilation at the severe treatment, which led to the higher water consumption, in the morning, and to the lower xylem water potential, in the afternoon; however, there was no gain of soybean dry matter. In both growth types, the intensity and duration of the severe level of soil moisture were not able to change the chlorophyll fluorescence. Soybean cultivars of both growth habits, subjected to severe levels of soil moisture from flowering to pod insertion, show no significant change for dry matter and grain yield.

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