scholarly journals Effects of Season of Burning on the Microenvironment of Fescue Prairie in Central Saskatchewan

2003 ◽  
Vol 117 (2) ◽  
pp. 257 ◽  
Author(s):  
O. W. Archibold ◽  
E. A. Ripley ◽  
L. Delanoy
Keyword(s):  
Plant Cover ◽  
Growing Season ◽  
Control Plot ◽  
Area Index ◽  
Growing Seasons ◽  
Soil Temperatures ◽  
Second Year ◽  
Long Term Impact ◽  
Season Of Burning

The microenvironmental effects of spring, summer and autumn burns were investigated for a small area of fescue prairie in Saskatchewan over two growing seasons. Maximum fire temperature in all burns exceeded 300°C at a height of 5-10 cm in the canopy. At a depth of 1 cm in the soil, temperature increased to 40°C during the summer burn, but was unaffected by burns at other seasons. Spring-burned grasses recovered to the same height as the unburned control plot by the end of the first summer. Grass height was similar in all plots by the end of the second growing season, but aboveground biomass in all burned plots was about half that of the control. Graminoid leaf area index at the end of the second growing season ranged from 0.65 in the control plot to 0.27 in the autumn burn. Surface albedos dropped to about 0.03 immediately after burning and took about 3 months to return to the pre-burn values near 0.20. By mid-June of the second year, albedos were similar in all plots. Soil temperatures at 50 cm depth in the burned plots were higher than in the control during the first summer and lower during the winter. The greatest winter snowpack (73 mm water equivalent) accumulated in the control, compared to 48, 35 and 25 mm in the spring, summer and autumn burned plots, respectively. In the first growing season the greatest demand for water occurred in the spring plot followed by the summer, control and autumn plots. In the second season water demand did not differ significantly among plots, reflecting the similarities in plant cover. The microenvironmental effects of a single burning episode in fescue prairie disappear rather quickly, so that there is little long-term impact on the vegetation.

scholarly journals Seasonal dynamics of methane emissions from a subarctic fen in the Hudson Bay Lowlands

2013 ◽  
Vol 10 (7) ◽  
pp. 4465-4479 ◽  
Author(s):  
K. L. Hanis ◽  
M. Tenuta ◽  
B. D. Amiro ◽  
T. N. Papakyriakou
Keyword(s):  
Soil Temperature ◽  
Air Temperature ◽  
Growing Season ◽  
Near Surface ◽  
Growing Seasons ◽  
Air Temperatures ◽  
Soil Temperatures ◽  
Surface Soil Temperature ◽  
Filling Method ◽  
Highly Correlated

Abstract. Ecosystem-scale methane (CH4) flux (FCH4) over a subarctic fen at Churchill, Manitoba, Canada was measured to understand the magnitude of emissions during spring and fall shoulder seasons, and the growing season in relation to physical and biological conditions. FCH4 was measured using eddy covariance with a closed-path analyser in four years (2008–2011). Cumulative measured annual FCH4 (shoulder plus growing seasons) ranged from 3.0 to 9.6 g CH4 m−2 yr−1 among the four study years, with a mean of 6.5 to 7.1 g CH4 m−2 yr−1 depending upon gap-filling method. Soil temperatures to depths of 50 cm and air temperature were highly correlated with FCH4, with near-surface soil temperature at 5 cm most correlated across spring, fall, and the shoulder and growing seasons. The response of FCH4 to soil temperature at the 5 cm depth and air temperature was more than double in spring to that of fall. Emission episodes were generally not observed during spring thaw. Growing season emissions also depended upon soil and air temperatures but the water table also exerted influence, with FCH4 highest when water was 2–13 cm below and lowest when it was at or above the mean peat surface.

scholarly journals Impact of soil scarification on reindeer pastures

Rangifer ◽  
1990 ◽  
Vol 10 (3) ◽  
pp. 99 ◽  
Author(s):  
Olof Eriksson ◽  
Tuomo Raunistola
Keyword(s):  
Standard Procedure ◽  
Plant Cover ◽  
Point Of View ◽  
Ground Vegetation ◽  
Long Term Effects ◽  
Surface Moisture ◽  
Positive Effects ◽  
Soil Scarification ◽  
Soil Temperatures

During recent years, soil scarification has become a standard procedure for improving seed beds after logging. Around 57 000 ha were treated, primarily through harrowing and ploughing, in the counties of Vâsterbotten and Norbotten during 1985. The positive effects of scarification, from a forestry point of view, are improved access to plant nutrients, raised soil temperatures and reduces surface moisture. The aim of the present study was to describe long-term changes in the ground vegetation following scarification. Harrowing affects 45-55% of the plant cover while ploughing affects 65-90%. 10 years after ploughing and harrowing about 20% of the surface is still without vegetation. Real long-term effects remain in dispute. It has been claimed that ploughing, at least, may lead to irreversible changes.

scholarly journals Influence of Cover Crop Termination on Ground Dwelling Arthropods in Organic Vegetable Systems

Insects ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 445
Author(s):  
Laura Depalo ◽  
Giovanni Burgio ◽  
Serena Magagnoli ◽  
Daniele Sommaggio ◽  
Francesco Montemurro ◽  
...  
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Growing Season ◽  
Ground Beetles ◽  
Generalist Predators ◽  
Rove Beetles ◽  
Green Manuring ◽  
Growing Seasons ◽  
Cash Crops ◽  
Second Year

A key aspect in cover crop management is termination before the cash crop is planted. The aim of this study was to assess the effects of termination methods on ground-dwelling arthropods. The conventional mechanical termination method—i.e., green manuring by means of a disc harrow—was compared to flattening using a roller crimper. Two different crop systems were investigated for two growing seasons; cauliflower was grown in autumn after the termination of a mixture of cowpea, pearl millet, and radish, and tomato was cropped in spring and summer after the termination of a mixture of barley and vetch. Ground beetles (Coleoptera: Carabidae), rove beetles (Coleoptera: Staphylinidae), and spiders (Araneae) were sampled by means of standard pitfall traps throughout the growing season of both cash crops. The roller crimper increased the overall abundance of ground beetles in the first growing season of both cash crops, whereas in the second year, no significant effect could be detected. Rove beetles were more abundant in plots where the cover crops were terminated by the roller crimper. Finally, green manuring increased the abundance of spiders, especially on the first sampling date after cover crop termination. Albeit different taxa showed different responses, the termination of cover crops by a roller crimper generally increased the abundance of ground dwelling arthropods. Given that most of the sampled species were generalist predators, their increased abundance could possibly improve biological control.

scholarly journals Long-term drainage reduces CO<sub>2</sub> uptake and increases CO<sub>2</sub> emission on a Siberian floodplain due to shifts in vegetation community and soil thermal characteristics

2016 ◽  
Vol 13 (14) ◽  
pp. 4219-4235 ◽  
Author(s):  
Min Jung Kwon ◽  
Martin Heimann ◽  
Olaf Kolle ◽  
Kristina A. Luus ◽  
Edward A. G. Schuur ◽  
...  
Keyword(s):  
Primary Production ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Thermal Characteristics ◽  
Growing Season ◽  
Co2 Uptake ◽  
Vegetation Community ◽  
Uptake Rates ◽  
Soil Temperatures

Abstract. With increasing air temperatures and changing precipitation patterns forecast for the Arctic over the coming decades, the thawing of ice-rich permafrost is expected to increasingly alter hydrological conditions by creating mosaics of wetter and drier areas. The objective of this study is to investigate how 10 years of lowered water table depths of wet floodplain ecosystems would affect CO2 fluxes measured using a closed chamber system, focusing on the role of long-term changes in soil thermal characteristics and vegetation community structure. Drainage diminishes the heat capacity and thermal conductivity of organic soil, leading to warmer soil temperatures in shallow layers during the daytime and colder soil temperatures in deeper layers, resulting in a reduction in thaw depths. These soil temperature changes can intensify growing-season heterotrophic respiration by up to 95 %. With decreased autotrophic respiration due to reduced gross primary production under these dry conditions, the differences in ecosystem respiration rates in the present study were 25 %. We also found that a decade-long drainage installation significantly increased shrub abundance, while decreasing Eriophorum angustifolium abundance resulted in Carex sp. dominance. These two changes had opposing influences on gross primary production during the growing season: while the increased abundance of shrubs slightly increased gross primary production, the replacement of E. angustifolium by Carex sp.  significantly decreased it. With the effects of ecosystem respiration and gross primary production combined, net CO2 uptake rates varied between the two years, which can be attributed to Carex-dominated plots' sensitivity to climate. However, underlying processes showed consistent patterns: 10 years of drainage increased soil temperatures in shallow layers and replaced E. angustifolium by Carex sp., which increased CO2 emission and reduced CO2 uptake rates. During the non-growing season, drainage resulted in 4 times more CO2 emissions, with high sporadic fluxes; these fluxes were induced by soil temperatures, E. angustifolium abundance, and air pressure.

Temporal patterns of ground flora response to fire in thinned Pinus–Quercus stands

2018 ◽  
Vol 48 (10) ◽  
pp. 1171-1183 ◽  
Author(s):  
Kevin G. Willson ◽  
Carson R. Barefoot ◽  
Justin L. Hart ◽  
Callie Jo Schweitzer ◽  
Daniel C. Dey
Keyword(s):  
Prescribed Fire ◽  
Stand Structure ◽  
Growing Season ◽  
Forest Understory ◽  
Stand Management ◽  
Ground Flora ◽  
Growing Seasons ◽  
Understory Richness ◽  
Growing Conditions

The ground flora stratum affects stand structure, resource acquisition, nutrient cycling, and taxonomic richness in forest ecosystems. Disturbances such as thinning and prescribed fire alter forest understory growing conditions that generally increase ground flora cover and richness. We studied annual changes in ground flora assemblages over three growing seasons after fire in thinned and frequently burned (3-year rotation) Pinus–Quercus stands. Our results corroborated trends from other studies that indicated greater ground flora richness and cover after thinning and burning compared with thin-only treatments. We also found that the stratum experienced relatively rapid succession between growing seasons that complimented the tolerance succession model. Forbs had reduced cover and richness from increasingly difficult growing conditions over time and were replaced by woody plants, shrubs, and seedlings. This likely occurred from changing competition dynamics that favored quick growth in the first growing season and long-term investment in vertical growth in the third growing season. The successful regeneration pathways also fit ground flora regeneration models and added a unique pathway to strengthen the predictive power of these models. As many stand management goals are focused towards improving biodiversity, prescribed fire and thinning may be used to increase understory richness in Pinus–Quercus stands.

Effect of Deficit Irrigation on Root-Shoot Development and Grain Yield of Winter Wheat

2014 ◽  
Vol 936 ◽  
pp. 2389-2395
Author(s):  
Bin Hu ◽  
Min Zhang
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Leaf Area Index ◽  
Deficit Irrigation ◽  
North China Plain ◽  
North China ◽  
Ground Surface ◽  
Growing Season ◽  
Area Index ◽  
Growing Seasons

In order to investigate the optimal water-saving and high-efficient irrigation patterns of winter wheat in North China Plain, during 2010－2011 and 2011－2012 winter wheat growing seasons, 3 irrigation treatments were conducted, i.e., irrigated 120 mm only at jointing stage (T1), irrigated 120 mm only at heading stages (T2), and irrigated 60 mm each at jointing and heading stages (T3), respectively, to study the effect of deficit irrigation on root-shoot development and grain yield of winter wheat in North China Plain. The results showed that under the condition of irrigated 120 mm during the winter wheat growing season, the treatment which irrigated 60 mm each at jointing and heading stages, the leaf area index significantly (LSD, P<0.05) increased at milky stage, which was mainly due to increase the leaf area index at 0－20 and more than 60 cm above the ground surface. The 2 growing season results revealed that dry matter accumulation at maturity stage in T3 was significantly (LSD, P<0.05) higher than those in T1 and T2. Compared with T2, the root length density in T1 and T3 were significantly (LSD, P<0.05) higher below the ground surface 50 cm. The results indicated that irrigated 60 mm each at jointing and heading stages during the winter wheat growing seasons, grain yield was the highest, which could be attributed to significantly (LSD, P<0.05) increase the spike numbers. Under the condition of irrigated 120 mm during the winter wheat growing seasons in North China Plain, it is suggests that winter wheat should be irrigated 60 mm each at jointing and heading stages, to achieve reasonable water use efficiency and grain yield.

Use of false rings in Austrian pine to reconstruct early growing season precipitation

2000 ◽  
Vol 30 (11) ◽  
pp. 1691-1697 ◽  
Author(s):  
Rupert Wimmer ◽  
Giorgio Strumia ◽  
Franz Holawe
Keyword(s):  
Growing Season ◽  
Pinus Nigra ◽  
Annual Rainfall ◽  
Dummy Variable ◽  
False Rings ◽  
Growing Seasons ◽  
Dry Conditions ◽  
Earlywood Width ◽  
Linear Regressions

As a consequence of dry conditions, coniferous trees may produce radially smaller diameter tracheids within their tree rings before regular latewood formation starts. The resulting structures, which are commonly called false rings, have demonstrated utility as an environmental indicator. However, the climatic patterns behind false rings and their potential use in climate reconstruction models have been barely explored. The study is based on 313 Austrian pines (Pinus nigra Arn.) sampled at 29 sites in the Viennese basin, an area with low annual rainfall, extended dry periods during the growing season and usually severely cold winters. False rings relate significantly to May precipitation, and in years with higher false-ring proportions, a relationships with the combination of wet April, dry May, and wet June is often seen. In linear regressions, the presence-absence of false rings was used as a "dummy" variable and, together with earlywood width, explained 31% of variation in May precipitation. Years with high false-ring proportions were found when May precipitation was less than half its long-term average. False-ring trends during the past 100 years were closely associated with changing May rainfall pattern. Overall, false rings are shown to be a useful tree-ring feature and may be applied successfully in dendroclimatic studies, i.e., in the reconstruction of very low rainfall months in early growing seasons during pre-instrumental periods.

Potential to double-crop plastic mulch

2008 ◽  
Vol 88 (1) ◽  
pp. 187-193 ◽  
Author(s):  
Doug Waterer ◽  
William Hrycan ◽  
Theresa Simms
Keyword(s):  
Light Transmission ◽  
Tomato Fruit ◽  
Growing Season ◽  
First Year ◽  
Vegetable Crops ◽  
Plastic Mulch ◽  
Weed Growth ◽  
Double Cropping ◽  
Soil Temperatures ◽  
Second Year

Double-cropping of plastic (polyethylene) mulches has the potential to increase the cost-effectiveness while reducing the environmental impact of this technology for enhancing growth of vegetable crops. In regions with a short growing season, double-cropping of soil mulches hinges on being able to leave the plastic in the field over winter. This extended exposure to the elements may alter the physical and optical characteristics of the mulch, thereby influencing crop productivity in the second year of use. This study evaluated the physical characteristics and efficacy of black, clear and infrared transmitting (IRT) mulches over two cropping seasons in Saskatchewan. The crops planted were pepper (Capsicum annuum) and cucumber (Cucumis sativus) in the first year and tomato (Lycopersicon esculentum) in the second year. Early-season soil temperatures appeared highest under the clear mulch in the first year, but once the crop canopy was established there was little difference in soil temperature among plots having different mulches. Higher yields of both cucumber and pepper were produced in the first year by clear mulch than by black mulch or without mulch. All mulches were still physically sound at the end of the first growing season, but light transmission through the clear and IRT mulches was reduced relative to new mulch. Much of this change was due to soil and other debris on the surface of the mulches. There was little further change in the physical condition or light transmission characteristics of the mulches through the second year of use. Weed growth under clear mulch in its second year appeared to reduce soil temperatures, particularly relative to new clear mulch. Mulch type, either newly laid or year-old, had no impact on yields of marketable tomatoes. More fruit reached full red color prior to harvest in response to clear mulch than to no mulch (bare soil). Yields of marketable tomato fruit obtained on year-old mulch of all types were comparable to yields obtained with new mulch. These data suggest that double-cropping of plastic mulches can be done without loss of crop yield and provide significant savings in materials, labor and disposal costs. While clear mulch was generally the most beneficial for the production of warm season vegetable crops, it did not prevent weed growth in the second year which was problematic. Key words: Wavelength selective, light transmission, cucumber, pepper, tomato

scholarly journals Effects of Nocturnal Soil Temperatures and Meloidogyne incognita Densities on Cotton Seedling Growth and the Interaction with Thielaviopsis basicola

Plant Disease ◽  
2006 ◽  
Vol 90 (4) ◽  
pp. 519-522 ◽  
Author(s):  
W. S. Monfort ◽  
T. L. Kirkpatrick ◽  
C. S. Rothrock
Keyword(s):  
Plant Height ◽  
Meloidogyne Incognita ◽  
Growth And Development ◽  
Growing Season ◽  
Thielaviopsis Basicola ◽  
Plant Growth And Development ◽  
Population Densities ◽  
Pathogen Population ◽  
Growing Seasons ◽  
Soil Temperatures

Controlled studies were conducted to evaluate the effects of soil temperatures typical of field conditions during the first 6 weeks of the growing season in Arkansas and different population densities of Meloidogyne incognita on damage to cotton (Gossypium hirsutum) seedlings associated with the interaction between M. incognita and Thielaviopsis basicola. Treatments consisted of varying nocturnal temperatures that approximated the temperatures that occurred during the 2001, 2002, and 2003 growing seasons in southeastern Arkansas. Nocturnal temperatures in the study were as follows: high, the first week at 15°C, followed by 3 weeks at 17°C, 1 week at 21°C, and 1 week at 17°C (approximating the 2002 season); medium, 3 weeks at 15°C and 3 weeks at 19°C (approximating the 2003 season); and low, 1 week at 15°C, 1 week at 13°C, 2 weeks at 17°C, 1 week at 15°C, and 1 week at 17°C (approximating the 2001 season). Pathogen population densities were either 0 or 100 chlamydospores of T. basicola per gram of soil and 0, 2,000, 4,000, or 8,000 eggs of M. incognita per 500 cm3of soil. Plant height and fresh top weight increased with an increase in nocturnal temperature across treatments. There were significant reductions in plant growth and development with T. basicola, but not with M. incognita, at these nocturnal temperatures, but decreased plant height and weight were seen where both pathogens were present in comparison with either pathogen alone. Trends of increased disease associated with T. basicola were observed with increasing inoculum rates of M. incognita, indicating that the interaction between T. basicola and M. incognita occurs even at soil temperatures below the minimum temperature reported as necessary for damage from M. incognita.

scholarly journals Ethylenediurea (EDU) effects on hybrid larch saplings exposed to ambient or elevated ozone over three growing seasons

2021 ◽  
Author(s):  
Evgenios Agathokleous ◽  
Mitsutoshi Kitao ◽  
Takayoshi Koike
Keyword(s):  
Photosynthetic Pigment ◽  
Ground Level ◽  
Growing Season ◽  
Growth Potential ◽  
Foliar Injury ◽  
Hybrid Larch ◽  
Ground Level Ozone ◽  
Growing Seasons ◽  
Elevated Ozone

AbstractGround-level ozone (O3) pollution is a persistent environmental issue that can lead to adverse effects on trees and wood production, thus indicating a need for forestry interventions to mediate O3 effects. We treated hybrid larch (Larix gmelinii var. japonica × L. kaempferi) saplings grown in nutrient-poor soils with 0 or 400 mg L−1 water solutions of the antiozonant ethylenediurea (EDU0, EDU400) and exposed them to ambient O3 (AOZ; 08:00 − 18:00 ≈ 30 nmol mol−1) or elevated O3 (EOZ; 08:00 − 18:00 ≈ 60 nmol mol−1) over three growing seasons. We found that EDU400 protected saplings against most effects of EOZ, which included extensive visible foliar injury, premature senescence, decreased photosynthetic pigment contents and altered balance between pigments, suppressed gas exchange and biomass production, and impaired leaf litter decay. While EOZ had limited effects on plant growth (suppressed stem diameter), it decreased the total number of buds per plant, an effect that was not observed in the first growing season. These results indicate that responses to EOZ might have implications to plant competitiveness, in the long term, as a result of decreased potential for vegetative growth. However, when buds were standardized per unit of branches biomass, EOZ significantly increased the number of buds per unit of biomass, suggesting a potentially increased investment to bud development, in an effort to enhance growth potential and competitiveness in the next growing season. EDU400 minimized most of these effects of EOZ, significantly enhancing plant health under O3-induced stress. The effect of EDU was attributed mainly to a biochemical mode of action. Therefore, hybrid larch, which is superior to its parents, can be significantly improved by EDU under long-term elevated O3 exposure, providing a perspective for enhancing afforestation practices.

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