530 research outputs found
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Spring establishment of orchardgrass and tall fescue seed crops with cereal companion crops
Orchardgrass and tall fescue seed crops are commonly springplanted
in Oregon, but do not produce a marketable crop during the first
growing season. Establishing orchardgrass and tall fescue with cereal
companion crops would provide income during the seeding year and could
increase seed production profits. This study was conducted to evaluate
the feasibility of establishing orchardgrass and tall fescue seed crops
with spring wheat, barley, and oats, and to examine the morphological,
physiological, seed yield, and economic responses to competition with
cereals. 'Hallmark' orchardgrass and 'Bonanza' tall fescue were
interplanted with 'Waverly' wheat, 'Steptoe' barley, and 'Cayuse' oats
in 15- and 30-cm rows at right angles to grass rows in March 1985 and
1986 near Corvallis, OR.
Spring cereals reduced the photosynthetic photon flux density
(PPFD) available for grass seedling growth, causing transient increases
in chlorophyll content and lower soil temperatures. Soil water content
was also depleted, causing increased stomatal resistance and lower
transpiration rate. Reductions in PPFD and soil water were responsible
for poor stand establishment and grass crop growth. The negative
effects on seedling establishment persisted after cereal harvest and
delayed grass regrowth until the following spring, resulting in low
fertile tiller populations. Consequently, first-year orchardgrass seed
yields were reduced by 40 and 53% in the two trials, whereas first-year
tall fescue seed yields were reduced by 61% in both trials. First-year
seed yields were similarly reduced by all three cereals. Second-year
orchardgrass seed yield was not influenced by companion cropping, but
second-year tall fescue yield increased by 15%. Cereal row spacing had
no effect on grass seed crop growth, physiology, or seed yield.
Seeding orchardgrass with spring wheat in 30-cm rows increased net
income by 139 per hectare more than planting alone. Drier than
normal conditions increased competitive effects of cereals, reducing
first-year seed yields and economic return. Irrigation or fall planting
may be the key to more favorable returns from companion cropping of
orchardgrass and tall fescue
Self-concealment: Integrative review and working model
An extensive empirical literature has focused on the self-concealment (SC) construct. In this article, we review 137 studies that used the Self-Concealment Scale (SCS) with varied populations (e.g., adolescent; intercultural; international; lesbian, gay, and bisexual; and intimate partner). We propose a working model for the psychology of SC and the mechanisms of action for its effects on well-being. A dual-motive conflict between urges to conceal and reveal is seen to play a central role in these health effects. Meta-analytic techniques identify significant associations for SC with 18 constructs falling into six general categories: antecedents, disclosure and concealment, emotion regulation, social well-being, psychological and physical health, and psychotherapy. We interpret these findings with reference to current research and theory on secret keeping and health as well as emotion- and self-regulatory processes. This first integrative review supports the construct validity of the SCS and demonstrates the value of the SC construct for the study of psychological phenomena in which secret keeping is a recognized issue
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Effect of cereal companion crops on the establishment of red fescue (Festuca rubra L.) for seed production
Some perennial grass seed crops such as red fescue (Festuca rubra
L.) do not produce a profitable seed crop during the first growing
season. The present establishment method in Oregon for red fescue seed
crops generally entails spring planting which does not satisfy
vernalization requirements for seed production in the year of planting.
This establishment procedure relies on the amortization of establishment
costs over the seed producing life of the stand. In Europe, perennial
grass seed crops are often established with annual companion crops such
as winter rape, flax, peas and cereals. Companion crops provide income
in the year of establishment, thereby increasing the profitability of
the seed production venture over the life of the stand. However, the
companion crop competes with the grass seed crop for light, soil
moisture and nutrients which often causes unsatisfactory establishment.
The primary objective of this study was to determine the
feasibility of establishing red fescue with cereal companion crops in
Oregon's Willamette Valley. The second objective was to examine the
influence of cereal companion crops, cultivars and row spacings on the
growth and environment of red fescue. This was investigated to identify
companion cropping methods that would be the least competitive with the establishing seed crop. The third objective was to evaluate the effect
of companion cropping on subsequent red fescue seed production and
income relationships over a two-year period.
Two experiments were initiated in October 1982 and October 1983 at
the Oregon State University Hyslop Crop Science Field Laboratory.
'Pennlawn' red fescue was established with two winter wheat cultivars,
'Hill 81' and 'Yamhill1, and two winter barley cultivars, 'Hesk' and
'Scio', as companion crops. Cereal companion crops were drilled in 15-,
30-, 45-, and 60-cm row spacings, perpendicular to red fescue rows. Red
fescue was also established without a companion crop as a control.
Companion crop tiller height, tillers mâ»ÂČ and leaf area tillerâ»Âč were measured to determine their influence on red fescue growth and
development during establishment. The effect of cereal companion crops
on red fescue environment was investigated by measuring photosynthetic
photon flux density (PPFD) incident on red fescue plants and by
determining soil moisture levels. Red fescue tiller height, leaf area,
dry matter production, and tillers mâ»ÂČ were examined to evaluate the
effect of companion crops on red fescue growth. Companion crop grain
yields were obtained to calculate additional revenues from establishment
with companion crops. First-year red fescue seed yield and yield
components were measured to determine the seed production capability of
red fescue established with cereal companion crops. Finally, a partial
budgeting technique was employed to evaluate the economic feasibility of
companion cropping in Oregon.
Cereal companion crops markedly reduced PPFD incident on red
fescue plants. This greatly decreased red fescue tiller mâ»ÂČ, dry matter mâ»ÂČ, individual tiller weight, and increased the height of tillers. Leaf area tillerâ»Âč was generally unaffected by companion crops.
Increasing companion crop row spacing resulted in more red fescue
tillers mâ»ÂČ, dry matter mâ»ÂČ and reduced etiolation of tillers because
of higher PPFD availability. Soil moisture content was not decreased by
establishment with cereal companion crops.
Although companion crops adversely affected red fescue growth
during the establishment year, first-year seed yield was not
significantly reduced. Red fescue seed yields ranged from 490 kg haâ»Âč
when planted with Hill 81 wheat to 654 kg haâ»Âč with Scio barley. The
seed yield of red fescue planted without a companion crop was 589 kg
haâ»Âč. Establishment with Yamhill wheat in 15-cm rows increased net
income over a two-year period by $416 haâ»Âč over monocultural red fescue.
Establishment with Hesk barley proved to be the least successful in
terms of income. Establishment with companion crops was shown to be
most profitable when cereal market prices were high and red fescue
prices low. The results of this research clearly indicate the
potential for increased profits by establishment of red fescue seed
crops with cereal companion crops
Quantification of Blue Carbon in Salt Marshes of the Pacific Coast of Canada
Tidal salt marshes are known to accumulate âblue carbonâ at high rates relative to their surface area, which render these systems among the Earthâs most efficient carbon (C) sinks. However, the potential for tidal salt marshes to mitigate global warming remains poorly constrained because of the lack of representative sampling of tidal marshes from around the globe, inadequate areal extent estimations, and inappropriate dating methods for accurately estimating C accumulation rates. Here we provide the first estimates of organic C storage and accumulation rates in salt marshes along the Pacific coast of Canada, within the United Nations Educational, Scientific and Cultural Organization (UNESCO) Clayoquot Sound Biosphere Reserve and Pacific Rim National Park Reserve, a region currently underrepresented in global compilations. Within the context of other sites from the Pacific coast of North America, these young Clayoquot Sound marshes have relatively low C stocks but are accumulating C at rates that are higher than the global average with pronounced differences between high and low marsh habitats. The average C stock calculated during the past 30 years is 54â5MgC ha-1 (meanâstandard error), which accounts for 81% of the C accumulated to the base of the marsh peat layer (67â9MgC ha-1/. The total C stock is just under one-third of previous global estimates of salt marsh C stocks, likely due to the shallow depth and young age of the marsh. In contrast, the average C accumulation rate (CAR) (184â50 gCm-2 yr-1 to the base of the peat layer) is higher than both CARs from salt marshes along the Pacific coast (112â12 gCm-2 yr-1/ and global estimates (91â7 gCm-2 yr-1/. This difference was even more pronounced when we considered individual marsh zones: CARs were significantly greater in high marsh (303â45 gCm-2 yr-1/ compared to the low marsh sediments (63â6 gCm-2 yr-1/, an observation unique to Clayoquot Sound among NE Pacific coast marsh studies. We attribute low CARs in the low marsh zones to shallow rooting vegetation, reduced terrestrial sediment inputs, negative relative sea level rise in the region, and enhanced erosional processes. Per hectare, CARs in Clayoquot Sound marsh soils are approximately 2â7 times greater than C uptake rates based on net ecosystem productivity in Canadian boreal forests, which highlights their potential importance as C reservoirs and the need to consider their C accumulation capacity as a climate mitigation co-benefit when conserving for other salt marsh ecosystem services
Quantification of blue carbon in salt marshes of the Pacific coast of Canada
Tidal salt marshes are known to accumulate "blue carbon " at high rates relative to their surface area, which render these systems among the Earth's most efficient carbon (C) sinks. However, the potential for tidal salt marshes to mitigate global warming remains poorly constrained because of the lack of representative sampling of tidal marshes from around the globe, inadequate areal extent estimations, and inappropriate dating methods for accurately estimating C accumulation rates. Here we provide the first estimates of organic C storage and accumulation rates in salt marshes along the Pacific coast of Canada, within the United Nations Educational, Scientific and Cultural Organization (UNESCO) Clayoquot Sound Biosphere Reserve and Pacific Rim National Park Reserve, a region currently underrepresented in global compilations. Within the context of other sites from the Pacific coast of North America, these young Clayoquot Sound marshes have relatively low C stocks but are accumulating C at rates that are higher than the global average with pronounced differences between high and low marsh habitats. The average C stock calculated during the past 30 years is 54 +/- 5 Mg C ha(-1) (mean +/- standard error), which accounts for 81 % of the C accumulated to the base of the marsh peat layer (67 +/- 9 Mg C ha(-1)). The total C stock is just under one-third of previous global estimates of salt marsh C stocks, likely due to the shallow depth and young age of the marsh. In contrast, the average C accumulation rate (CAR) (184 +/- 50 g C m(-2) yr(-1) to the base of the peat layer) is higher than both CARs from salt marshes along the Pacific coast (112 +/- 12 g C m(-2) yr(-1)) and global estimates (91 +/- 7 g C m(-2) yr(-1)). This difference was even more pronounced when we considered individual marsh zones: CARs were significantly greater in high marsh (303 +/- 45 g C m(-2) yr(-1)) compared to the low marsh sediments (63 +/- 6 g C m(-2) yr(-1)), an observation unique to Clayoquot Sound among NE Pacific coast marsh studies. We attribute low CARs in the low marsh zones to shallow-rooting vegetation, reduced terrestrial sediment inputs, negative relative sea level rise in the region, and enhanced erosional processes. Per hectare, CARs in Clayoquot Sound marsh soils are approximately 2-7 times greater than C uptake rates based on net ecosystem productivity in Canadian boreal forests, which highlights their potential importance as C reservoirs and the need to consider their C accumulation capacity as a climate mitigation co-benefit when conserving for other salt marsh ecosystem services
Post-Harvest Residue Management for Fine Fescue Seed Crops in Oregon
On-farm trials were conducted from 1992 to 1995 to investigate the efficacy of alternative post-harvest residue management practices for production of fine-leaf fescue seed crops, creeping red fescue (Festuca rubra L.) and Chewings fescue (F. rubra L. ssp. commutata Gaud.). Seed yield and seed quality were maintained in Chewings fescue seed crops without burning when residue management techniques removed most of the straw and stubble remaining after harvest. Seed yield was reduced to unacceptable levels by all nonthermal management practices in creeping red fescue
Residue Management and Establishment Systems for Annual Ryegrass Seed Production
Two on-farm trials were established in 1994 to investigate low cost crop residue management and seeding practices in two cultivars of annual ryegrass (Lolium multiflorum Lam.) grown for seed production in Oregon\u27s Willamette Valley. Sites varied by soil type and drainage. Stand density was greater in no-till and volunteer established plots at both locations, but straw removal by baling had no effect on stand density. Fertile tiller number and seed yield was reduced in drill sown plots in TAM-90 (poorly drained site); also, fertile tiller number was fewer where no straw removal preceded no-till or volunteer establishment. No difference in spring tillering characteristics or seed yield was observed in Gulf (better drained site)
Na incorporation into Cu(In,Ga)Se2 thin-film solar cell absorbers deposited on polyimide: Impact on the chemical and electronic surface structure
The following article appeared in Journal of Applied Physics 111.3 (2012): 034903 and may be found at http://scitation.aip.org/content/aip/journal/jap/111/3/10.1063/1.3679604Na has deliberately been incorporated into Cu(In,Ga)Se2 (CIGSe) chalcopyrite thin-film solar cell absorbers deposited on Mo-coated polyimide flexible substrates by adding differently thick layers of NaF in-between CIGSe absorber and Mo back contact. The impact of Na on the chemical and electronic surface structure of CIGSe absorbers with various Cu-contents deposited at comparatively low temperature (420 C) has been studied using x-ray photoelectron and x-ray excited Auger electron spectroscopy. We observe a higher Na surface content for the Cu-richer CIGSe samples and can distinguish between two different chemical Na environments, best described as selenide-like and oxidized Na species, respectively. Furthermore, we find a Cu-poor surface composition of the CIGSe samples independent of Na content and - for very high Na contents - indications for the formation of a (Cu,Na)-(In,Ga)-Se like compound. With increasing Na surface content, also a shift of the photoemission lines to lower binding energies could be identified, which we interpret as a reduction of the downward band bending toward the CIGSe surface explained by the Na-induced elimination of In Cu defects.X.S., R.F., D.G., R.G.W., and M.B. are grateful to the Helmholtz-Association for financial support (VH-NG-423). R.F. also acknowledges the support by the German Academic Exchange Agency (DAAD; 331 4 04 002)
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