Morphological and water-stress characteristics of three Douglas-fir stocktypes in relation to seedling performance under different soil moisture conditions

New Forests ◽  
1993 ◽  
Vol 7 (1) ◽  
pp. 1-17 ◽  
Author(s):  
R. Rose ◽  
J. F. Gleason ◽  
M. Atkinson
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Douglas Fir ◽  
Seedling Performance ◽  
Moisture Conditions

Effects of contrasting light and soil moisture availability on the growth and biomass allocation of Douglas-fir and red alder

2003 ◽  
Vol 33 (1) ◽  
pp. 106-117 ◽  
Author(s):  
Samuel S Chan ◽  
Steven R Radosevich ◽  
Amy T Grotta
Keyword(s):  
Soil Moisture ◽  
Biomass Allocation ◽  
Competitive Ability ◽  
Field Capacity ◽  
Douglas Fir ◽  
Red Alder ◽  
Moisture Availability ◽  
Biomass Components ◽  
Soil Moisture Availability ◽  
Moisture Conditions

We examined growth and biomass allocation of individual Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and red alder (Alnus rubra Bong.) seedlings grown for 3 years under contrasting combinations of light and water. Alder growth was always greater than Douglas-fir. Full sunlight and soil moisture at field capacity caused large differences in size between the two species. With limited light and water, differences were smaller. Under full light and limited water, Douglas-fir allocated a high portion of its biomass to roots, whereas red alder allocated a high percentage to aboveground biomass components. Under light and water resource-limiting situations, red alder allocated more mass to stem, whereas Douglas-fir allocated more to roots. Red alder growth responded negatively to water limitation, whereas Douglas-fir did not. Red alder exhibited greater foliage plasticity to light. Species differences in size and allocation in response to resource availability may determine pathways by which Douglas-fir and red alder interact in a mixed community. Our findings support the hypothesis that the potential of species to use growth-limiting resources is an indicator of competitive ability. We suggest that red alder and Douglas-fir can co-exist under conditions of full light and limiting soil moisture availability. Furthermore, when contrasted with red alder, Douglas-fir's relatively greater tolerances to low light allow it to better persist in the understory. Red alder's rapid early growth and competitive ability will be superior under full light and nonlimiting soil moisture conditions.

Influence of selected environmental factors on glyphosate efficacy when applied to awnless barnyard grass (Echinochloa colona (L.) Link)

1997 ◽  
Vol 48 (5) ◽  
pp. 695 ◽  
Author(s):  
Songyod Tanpipat ◽  
Steve W. Adkins ◽  
John T. Swarbrick ◽  
Mark Boersma
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Relative Humidity ◽  
Environmental Factors ◽  
Field Capacity ◽  
Barnyard Grass ◽  
Temperature Regimes ◽  
Severe Water Stress ◽  
Moisture Conditions

Glasshouse experiments were conducted to determine the effects of various environmental factors on glyphosate efficacy when applied to Echinochloa colona (L.) Link (awnless barnyard grass) plants. The variables examined were 4 soil moisture conditions (29, 42, 55, and 100% of field capacity), 2 levels of irradiance (400 and 800 µmol/m2· s), 3 temperature regimes (20/15, 30/25, and 35/30°C; day/night), and 2 levels of relative humidity (92 and 65%). The efficacy of 360 g acid equivalent glyphosate/ha was greatest when applied to well-watered (field capacity) plants that were placed under cool (20/25°C) and humid (92% relative humidity) conditions. The efficacy was least when applied to plants under severe water stress (29% of field capacity) that were placed under hot (35/30°C) and less humid (65% relative humidity) conditions. In all experiments, efficacy was not altered by the level of irradiance.

Evaluation of Presswheels and Seed Coverers for Direct Seeding of Brassica

HortScience ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 599E-600
Author(s):  
Regina P. Bracy ◽  
Richard L. Parish
Keyword(s):  
Soil Moisture ◽  
Sandy Loam ◽  
Visual Observation ◽  
Mustard Seed ◽  
High Soil Moisture ◽  
Loam Soil ◽  
Direct Seeded ◽  
Plant Emergence ◽  
Moisture Conditions ◽  
Determine Effect

Improved stand establishment of direct-seeded crops has usually involved seed treatment and/or seed covers. Planters have been evaluated for seed/plant spacing uniformity, singulation, furrow openers, and presswheel design; however, effects of presswheels and seed coverers on plant establishment have not been widely investigated. Five experiments were conducted in a fine sandy loam soil to determine effect of presswheels and seed coverers on emergence of direct-seeded cabbage and mustard. Seed were planted with Stanhay 870 seeder equipped with one of four presswheels and seed coverers. Presswheels included smooth, mesh, concave split, and flat split types. Seed coverers included standard drag, light drag, paired knives, and no coverer. Soil moisture at planting ranged from 8% to 19% in the top 5 cm of bed. Differences in plant counts taken 2 weeks after planting were minimal with any presswheel or seed coverer. Visual observation indicated the seed furrow was more completely closed with the knife coverer in high soil moisture conditions. All tests received at least 14 mm of precipitation within 6 days from planting, which may account for lack of differences in plant emergence.

EFFECT OF DEFICIT IRRIGATION ON YIELD, RELATIVE LEAF WATER CONTENT, LEAF PROLINE ACCUMULATION AND CHLOROPHYLL STABILITY INDEX OF COTTON–MAIZE CROPPING SEQUENCE

2013 ◽  
Vol 50 (3) ◽  
pp. 407-425 ◽  
Author(s):  
T. SAMPATHKUMAR ◽  
B. J. PANDIAN ◽  
P. JEYAKUMAR ◽  
P. MANICKASUNDARAM
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Water Content ◽  
Deficit Irrigation ◽  
Stability Index ◽  
Moisture Gradient ◽  
Proline Content ◽  
Leaf Water Content ◽  
Chlorophyll Stability Index ◽  
Soil Moisture Gradient

SUMMARYWater stress induces some physiological changes in plants and has cumulative effects on crop growth and yield. Field experiments were conducted to study the effect of deficit irrigation (DI) on yield and some physiological parameters in cotton and maize in a sequential cropping system. Creation of soil moisture gradient is indispensable to explore the beneficial effects of partial root zone drying (PRD) irrigation and it could be possible only through alternate deficit irrigation (ADI) practice in paired row system of drip layout that is commonly practiced in India. In the present study, PRD and DI concepts (creation of soil moisture gradient) were implemented through ADI at two levels of irrigation using drip system. Maize was sown after cotton under no till condition without disturbing the raised bed and drip layout. Relative leaf water content (RLWC) and chlorophyll stability index (CSI) of cotton and maize were reduced under water stress. A higher level of leaf proline content was observed under severe water-stressed treatments in cotton and maize. RLWC and CSI were highest and leaf proline content was lowest in mild water deficit (ADI at 100% crop evapotranspiration once in three days) irrigation in cotton and maize. The same treatments registered higher values for crop yields, net income and benefit cost ratio for both the crops.

scholarly journals Root Growth Potential and Microsite Effects on Conifer Seedling Establishment in Northern Idaho

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 597
Author(s):  
Jacob A. Reely ◽  
Andrew S. Nelson
Keyword(s):  
Root Growth ◽  
Douglas Fir ◽  
Seedling Quality ◽  
Growth Potential ◽  
Larix Occidentalis ◽  
Root Growth Potential ◽  
Western Larch ◽  
Neighborhood Conditions ◽  
Seedling Performance ◽  
Survival And Growth

Environmental conditions and seedling quality interact to produce complex patterns of seedling survival and growth. Root growth potential (RGP) is one metric of seedling quality that can be rapidly measured prior to planting, but the correlation of RGP and seedling performance is not consistent across studies. Site factors including microsite objects that cast shade and competing vegetation can also influence seedling performance. We examined the effects of RGP, presence/absence of a microsite object, and competition cover on the survival and growth of three native conifers to the Inland Northwest, USA, over 5 years. We found that RGP had no effect on the survival or growth of western larch (Larix occidentalis), Douglas fir (Pseudotsuga menziesii var. glauca), and grand fir (Abies grandis) at a mesic north aspect site and a xeric south aspect site. Comparatively, the presence of a microsite increased the odds of survival by 37% for western larch and 158% for grand fir, while the absence of forb cover increased the odds of survival of western larch by 72% and of grand fir by 26%. Douglas fir was less sensitive to microsites and competition. The strong effects of neighborhood conditions around seedlings help inform silvicultural practices to enhance the establishment of western larch and grand fir, including planting seedlings near shading objects and competition control, while these practices may not be as important for Douglas fir.

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