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1.
Tania Schoennagel Monica G. Turner Daniel M. Kashian Andrew Fall 《Landscape Ecology》2006,21(8):1281-1296
A probabilistic spatial model was created based on empirical data to examine the influence of different fire regimes on stand
structure of lodgepole pine (Pinus contorta var. latifolia) forests across a >500,000-ha landscape in Yellowstone National Park, Wyoming, USA. We asked how variation in the frequency
of large fire events affects (1) the mean and annual variability of age and tree density (defined by postfire sapling density
and subsequent stand density) of lodgepole pine stands and (2) the spatial pattern of stand age and density across the landscape.
The model incorporates spatial and temporal variation in fire and serotiny in predicting postfire sapling densities of lodgepole
pine. Empirical self-thinning and in-filling curves alter initital postfire sapling densities over decades to centuries. In
response to a six-fold increase in the probability of large fires (0.003 to 0.018 year−1), mean stand age declined from 291 to 121 years. Mean stand density did not increase appreciably at high elevations (1,029
to 1,249 stems ha−1) where serotiny was low and postfire sapling density was relatively low (1,252 to 2,203 stems ha−1). At low elevations, where prefire serotiny and postfire lodgepole pine density are high, mean stand densities increased
from 2,807 to 7,664 stems ha−1. Spatially, the patterns of stand age became more simplified across the landscape, yet patterns of stand density became more
complex. In response to more frequent stand replacing fires, very high annual variability in postfire sapling density is expected,
with higher means and greater variation in stand density across lodgepole pine landscapes, especially in the few decades following
large fires. 相似文献
2.
Rachel A. Loehman Robert E. Keane Lisa M. Holsinger Zhiwei Wu 《Landscape Ecology》2017,32(7):1447-1459
Context
Interactions among disturbances, climate, and vegetation influence landscape patterns and ecosystem processes. Climate changes, exotic invasions, beetle outbreaks, altered fire regimes, and human activities may interact to produce landscapes that appear and function beyond historical analogs.Objectives
We used the mechanistic ecosystem-fire process model FireBGCv2 to model interactions of wildland fire, mountain pine beetle (Dendroctonus ponderosae), and white pine blister rust (Cronartium ribicola) under current and future climates, across three diverse study areas.Methods
We assessed changes in tree basal area as a measure of landscape response over a 300-year simulation period for the Crown of the Continent in north-central Montana, East Fork of the Bitterroot River in western Montana, and Yellowstone Central Plateau in western Wyoming, USA.Results
Interacting disturbances reduced overall basal area via increased tree mortality of host species. Wildfire decreased basal area more than beetles or rust, and disturbance interactions modeled under future climate significantly altered landscape basal area as compared with no-disturbance and current climate scenarios. Responses varied among landscapes depending on species composition, sensitivity to fire, and pathogen and beetle suitability and susceptibility.Conclusions
Understanding disturbance interactions is critical for managing landscapes because forest responses to wildfires, pathogens, and beetle attacks may offset or exacerbate climate influences, with consequences for wildlife, carbon, and biodiversity.3.
Domenico Ronga Domenica Villecco Massimo Zaccardelli 《The Journal of Horticultural Science and Biotechnology》2019,94(5):664-675
Cardoon (Cynara cardunculus L.) is considered as one of the most suitable energy crops for Southern Europe. The aim of this work was to outline the effects of organic fertilisers on the productivity and the global warming potential (GWP) on cardoon production. Six fertilisers (N 100 kg ha?1, N 50 kg ha?1, Compost 30 t ha?1, Compost 15 t ha?1 + N 25 kg ha?1, 3 t ha?1 of defatted oilseed meals of sunflower, 3 t ha?1 of defatted oilseed meals of Brassica carinata), and unfertilised control, were evaluated on two cultivars (‘Gobbo di Nizza’ and ‘Altilis 41’) in a split-plot experiment. Defatted oilseed meal of sunflower recorded higher total dry weight (+10%), seed yield (+17%), nitrogen use efficiency (+14%) and better GWP (?66%) compared to the other organic fertilisers and performing as well as N 100 kg ha?1. Altilis 41 cultivar showed the highest aboveground total dry weight (10 t ha?1 y?1), seed yield (1.7 t ha?1 y?1), stalk dry weight (7 t ha?1 y?1) and head dry weight (3 t ha?1 y?1). Our results highlighted that by combining suitable cultivar and fertilisation strategies, it could be possible to increase the production sustainability of C. cardunculus. 相似文献
4.
Simulating the reciprocal interaction of forest landscape structure and southern pine beetle herbivory using LANDIS 总被引:2,自引:0,他引:2
David M. Cairns Charles W. Lafon John D. Waldron Maria Tchakerian Robert N. Coulson Kier D. Klepzig Andrew G. Birt Weimin Xi 《Landscape Ecology》2008,23(4):403-415
The reciprocal interaction of landscape structure and ecological processes is a cornerstone of modern landscape ecology. We
use a simulation model to show how landscape structure and herbivory interact to influence outbreaks of southern pine beetle
(Dendroctonus frontalis Zimmermann) in a landscape representative of the southern Appalachian Mountains, USA. We use LANDIS and its biological disturbance
agent module to simulate the effects of landscape composition (proportion of landscape in host area) and host aggregation
on the size and severity of insect outbreaks and the persistence of the host species, Table Mountain Pine (Pinus pungens Lamb.). We find that landscape composition is less important in the modeled landscapes than host aggregation in structuring
the severity of insect outbreaks. Also, simulated southern pine beetle outbreaks over time tend to decrease the aggregation
of host species on the landscape by fragmenting large patches into smaller ones, thereby reducing the severity of future outbreaks.
Persistence of Table Mountain pine decreases throughout all simulations regardless of landscape structure. The results of
this study indicate that when considering alternative restoration strategies for insect-affected landscapes, it is necessary
to consider the patterns of hosts on the landscape as well as the landscape composition. 相似文献
5.
Edward J. Rykiel Jr. Robert N. Coulson Peter J. H. Sharpe Timothy F. H. Allen Richard O. Flamm 《Landscape Ecology》1988,1(3):129-139
Landscapes are the resultant of ecological processes and events operating on many different space-time scales. Large scale disturbance is recognized as a major influence on landscape patterns, but the impact of small scale events is often overlooked. We develop an hierarchical framework to relate lightning and bark beetle population dynamics to the southern pine forest landscape using the concepts of disturbance propagation and amplification. The low level lightning disturbance can be propagated to the landscape level when weather and forest stand structure facilitate bark beetle epidemics. We identify epidemics as biotically-driven episodes that alter landscape structure. The concept of the landscape as the spatial dimension of these episodes is represented in a conceptual model linking insect-host and landscape mosaic interactions. 相似文献
6.
Apurba Bandyopadhyay Dipak Kumar Ghosh Maheswarappa Halli Parameswarappa Jagadish Timsina 《International Journal of Fruit Science》2019,19(1):57-74
Fertigation has the potential to reduce extra chemical load by improving nutrient and water use efficiency of coconut (Cocos nucifera L.), but studies demonstrating the fertilizer reduction through drip irrigation in comparison to conventional ring basin method are rare in the Eastern Indo-Gangetic Plains (IGP) of South Asia. A long-term field experiment was conducted during 2007–2013 in West Bengal, India, to study the effect of fertigation on coconut var. DXT. The experiment was laid out in a randomised complete block design (RCBD) with six treatments (control – no fertilizers and water applied with drip irrigation; 25%, 50%, 75% and 100% of the recommended dose of fertilizer (RDF), each applied with drip irrigation; and 100% of the RDF and water applied with ring basin method of irrigation (i.e., conventional method)). Nuts yield was significantly higher for 75% of RDF (24.44 t ha?1 year?1) followed by 100% of RDF, each drip irrigation (23.79 t ha?1 year?1) compared to control (21.89 t ha?1 year?1). Copra yield was significantly higher for 75% of RDF (3.19 t ha?1) compared to 100% of RDF (3.12 t ha?1) and no fertilizer (1.87 t ha?1). Nitrogen (N), phosphorus (P) and potassium (K) contents of soil increased by 4.9%, 10.4% and 9.4%, respectively, with 75% of RDF applied through drip irrigation. Microbial population showed inverse relationship with amount of fertilizer application. The most water-use efficient fertigation treatment was 75% RDF (13.48 kg copra m?3) followed by 100% RDF (13.18 kg copra m?3) with drip irrigation as compared to conventional way soil application of fertilizers through ring basin method of irrigation (4.23 kg copra m?3). Role of N on yield variability was most prominent by both available soil N status (R2 = 0.49**) and leaf N concentration (R2 = 0.51**). The study indicated that there is a great scope for reducing the N, P and K fertilizers by up to 25% of the present RDFs for coconut when applied through drip irrigation compared to ring basin method of irrigation for its higher productivity and profitability through efficient use of nutrients and water in the Eastern IGP of South Asia. 相似文献
7.
Historic range of variability in landscape structure in subalpine forests of the Greater Yellowstone Area,USA 总被引:4,自引:0,他引:4
A measure of the historic range of variability (HRV) in landscape structure is essential for evaluating current landscape
patterns of Rocky Mountain coniferous forests that have been subjected to intensive timber harvest. We used a geographic information
system (GIS) and FRAGSTATS to calculate key landscape metrics on two ∼130,000-ha landscapes in the Greater Yellowstone Area,
USA: one in Yellowstone National Park (YNP), which has been primarily shaped by natural fires, and a second in the adjacent
Targhee National Forest (TNF), which has undergone intensive clearcutting for nearly 30 years. Digital maps of the current
and historical landscape in YNP were developed from earlier stand age maps developed by Romme and Despain. Maps of the TNF
landscape were adapted from United States Forest Service Resource Information System (RIS) data. Key landscape metrics were
calculated at 20-yr intervals for YNP for the period from 1705-1995. These metrics were used to first evaluate the relative
effects of small vs. large fire events on landscape structure and were then compared to similar metrics calculated for both
pre- and post-harvest landscapes of the TNF. Large fires, such as those that burned in 1988, produced a structurally different
landscape than did previous, smaller fires (1705-1985). The total number of patches of all types was higher after 1988 (694
vs. 340-404 before 1988), and mean patch size was reduced by almost half (186 ha vs. 319-379 ha). The amount of unburned forest
was less following the 1988 fires (63% vs. 72-90% prior to 1988), yet the number of unburned patches increased by nearly an
order of magnitude (230 vs. a maximum of 41 prior to 1988). Total core area and mean core area per patch decreased after 1988
relative to smaller fires (∼73,700 ha vs. 87,000-110,000 ha, and 320 ha vs. 2,123 ha, respectively). Notably, only edge density
was similar (17 m ha−1 after 1988) to earlier landscapes (9.8-14.2 m ha−1).Three decades of timber harvesting dramatically altered landscape structure in the TNF. Total number of patches increased
threefold (1,481 after harvest vs. 437 before harvest), and mean patch size decreased by ∼70% (91.3 ha vs. 309 ha). None of
the post-harvest landscape metrics calculated for the TNF fell within the HRV as defined in YNP, even when the post-1988 landscape
was considered. In contrast, pre-harvest TNF landscape metrics were all within, or very nearly within, the HRV for YNP. While
reference conditions such as those identified by this study are useful for local and regional landscape evaluation and planning,
additional research is necessary to understand the consequences of changes in landscape structure for population, community,
ecosystem, and landscape function.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
Matthew Braun Yuguang Bai Brian McConkey Richard Farrell J. T. Romo Dan Pennock 《Landscape Ecology》2013,28(4):709-723
Much of the remaining native rangelands in Canada are topographically complex. The flux of greenhouse gases (GHGs) in rangelands of hummocky terrain has not been adequately studied, leaving a gap in the national GHG sources and sinks budget. The objectives of this study were to determine the effects of topography and mowing on carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) flux and to correlate these fluxes to abiotic and biotic factors. GHG flux was studied on six landform elements, including north-facing concave and, south-facing concave and convex, upland and depressions, in the Northern Mixedgrass Prairie of Canada over 2 years with mowing being imposed in early spring. GHG fluxes showed strong temporal variations, ranging from 3.0 to 40.4 kg CO2–C ha?1 d?1, 0.1 to 2.6 g N2O–N ha?1 d?1, and ?0.25 to ?0.01 g CH4–C ha?1 d?1. GHG fluxes responded to changes in soil water and soil temperature across the landscape. The largest production of CO2 was recorded in depression mainly due to its more favourable soil water conditions. Mowing enhanced CO2 flux more than CH4 and N2O fluxes. Dominant plant species varied among the six landform elements, but using plant community type as the direct indicator for GHG emissions in grasslands may not always be reliable when precipitation is low. The net emissions of GHGs from Saskatchewan rangeland was relatively low, but the potential to increase emissions through changes in land management could be high. Our results suggest that in the Mixedgrass Prairie, best management practices for maintaining grassland health such as moderate grazing may also reduce GHG emissions. 相似文献
9.
Yusuf Ucar Abdullah Kadayıfcı Mehmet Atilla Askın Abdullah Kankaya Ulas Senyiğit Fatma Yıldırım 《Erwerbs-Obstbau》2016,58(3):159-167
This study was conducted in 2007–2008 to determine the effects of different irrigation regimes on yield, quality and water-yield relationships of young dwarf ‘Gala, Galaxy’ apple trees in Isparta-Turkey. Irrigation water was applied based on a ratio of class A pan evaporation (rates of 0.0 (kcp0), 0.25 (kcp1), 0.50 (kcp2), 0.75 c (kcp3), 1.00 (kcp4) and 1.25 (kcp5)) with 5-day intervals. The effects of irrigation regimes on yield and fruit weight were statistically significant. Seasonal evapotranspiration was measured as 246.5–608.2 mm and 289.3–631.9 mm in 2007 and 2008, respectively. Water use efficiency lead to a yield ranging from 0.0023 to 0.0055 t ha?1mm?1 and from 0.0033 to 0.0111 t ha?1mm?1 and irrigation water use efficiency varies from 0.0009 to 0.0073 t ha?1mm?1 and from 0.0045 to 0.0186 t ha?1mm?1 in 2007 and 2008, respectively. The annual average yield response factor, ky, was 1.22. As a result of the research, it was concluded that the irrigation schedule for the 0.75 kcp3 treatment, applying 0.75 of evaporation from class A pan, could be used in the irrigation of young dwarf apple trees without evident reduction in yield and that high water use efficiencies could be obtained. 相似文献
10.
Context
An increase in the incidence of large wildfires worldwide has prompted concerns about the resilience of forest ecosystems, particularly in the western U.S., where recent changes are linked with climate warming and 20th-century land management practices.Objectives
To study forest resilience to recent wildfires, we examined relationships among fire legacies, landscape features, ecological conditions, and patterns of post-fire conifer regeneration.Methods
We quantified regeneration across 182 sites in 21 recent large fires in dry mixed-conifer forests of the U.S. northern Rockies. We used logistic and negative binomial regression to predict the probability of establishment and abundance of conifers 5–13 years post-fire.Results
Seedling densities varied widely across all sites (0–127,500 seedlings ha?1) and were best explained by variability in distance to live seed sources (β = ?0.014, p = 0.002) and pre-fire tree basal area (β = 0.072, p = 0.008). Beyond 95 m from the nearest live seed source, the probability of seedling establishment was low. Across all the fires we studied, 75 % of the burned area with high tree mortality was within this 95-m threshold, suggesting the presence of live seed trees to facilitate natural regeneration.Conclusions
Combined with the mix of species present within the burn mosaic, dry mixed-conifer forests will be resilient to large fires across our study region, provided that seedlings survive, fire do not become more frequent, high-severity patches do not get significantly larger, and post-fire climate conditions remain suitable for seedling establishment and survival.11.
Yusuf Ucar Abdullah Kadayıfcı Mehmet Atilla Aşkın Abdullah Kankaya Ulaş Şenyiğit Fatma Yıldırım 《Erwerbs-Obstbau》2016,58(3):169-175
This study was conducted in 2007 and 2008 in order to determine the effects of irrigation frequency on the yield and quality parameters of dwarf trees of the apple cultivar ‘Gala, Galaxy’ in the first and second year of cultivation. Irrigation water was applied at 3?, 5?, 7?, and 10-day intervals as much as the amount of water consumed from the field capacity. Statistical analysis revealed that the effects of irrigation frequency on yield were significant. Since the trees used in the experiment showed mainly vegetative growth, the effects of irrigation frequency on the fruit quality characteristics varied. Irrigation water amount was applied as 355.7–446.5 mm and 359.2–538.9 mm to the experimental treatments in 2007 and 2008, respectively. The evapotranspiration measured was in the range 400.7–491.5 mm in 2007 but in the range 440.2–600.5 mm in 2008, while the yields in the same years ranged from 1.54 to 2.84 t ha?1 and from 2.61 to 6.06 t ha?1. Water use efficiency varied between 2.40 and 4.80 t ha?1mm?1 in the first year of the experiment but between 3.45 and 7.08 t ha?1mm?1 in the second year. The I2 treatment, in which the highest yield and water use efficiency were recorded in both years of the experiment under the experimental conditions, was determined as the irrigation scheduling. 相似文献
12.
In this study, it was aimed to perform an energy analysis of organic grape production in Besni district of Ad?yaman province of Turkey. In order to determine the energy input-output of organic grape production, the observations and surveys were performed in the 82 organic grape growers in Ad?yaman province. 82 farms were selected on full count method. The data obtained from study were collected from 82 different farms (398.32 hectares) by face to face questionnaires and observations. In organic grape farms, energy input-output analysis was also determinated by observation and survey methods in production season in 2015. In organic grape production, energy input was calculated as 24,875.06?MJ?ha?1 and energy output was calculated as 163,430?MJ?ha?1. Energy use efficiency, energy productivity, specific energy and net energy in organic grape production were calculated as 6.57; 0.56?kg?MJ?1, 1.79?MJ?kg?1 and 138,554.94?MJ?ha?1, respectively. 相似文献
13.
This research aims to make an analysis of energy use efficiency of apple (‘Starkrimson Delicious’ and ‘Golden Delicious’) production in E?irdir region of Turkey, during the production season of 2012. Production data this research was collected in 2013. In order to determine the energy use efficiency of apple, various surveys have been conducted in 71 apple farms, selected through Simple Random Sampling method, located in E?irdir region of Turkey. The data have been collected through face to face questionnaires and first hand observations. The energy input and output values in apple production have been calculated as 34,703.63 MJ ha?1 and 95,034 MJ ha?1, respectively. Energy inputs consist of diesel fuel energy by 29.04?%, chemical fertilizers energy by 24.28?%, machinery energy by 15.70?%, chemical energy by 9.84?%, human labor energy by 8.54?%, electricity energy by 5.63?%, irrigation energy by 3.97?%, farmyard manure energy by 2.88?% and lime energy by 0.12?%. Energy use efficiency, energy productivity, specific energy and net energy in apple production have been calculated as 2.74, 1.16 kg MJ?1, 0.86 MJ kg?1 and 60,330.36 MJ ha?1, respectively. The total energy input consumed has been classified as direct, by 47.17?%, indirect, by 52.83?%, renewable, by 15.38?% and non-renewable, by 74.62?%. 相似文献
14.
Context
Growing evidence suggests that climate change could substantially alter forest disturbances. Interactions between individual disturbance agents are a major component of disturbance regimes, yet how interactions contribute to their climate sensitivity remains largely unknown.Objectives
Here, our aim was to assess the climate sensitivity of disturbance interactions, focusing on wind and bark beetle disturbances.Methods
We developed a process-based model of bark beetle disturbance, integrated into the dynamic forest landscape model iLand (already including a detailed model of wind disturbance). We evaluated the integrated model against observations from three wind events and a subsequent bark beetle outbreak, affecting 530.2 ha (3.8 %) of a mountain forest landscape in Austria between 2007 and 2014. Subsequently, we conducted a factorial experiment determining the effect of changes in climate variables on the area disturbed by wind and bark beetles separately and in combination.Results
iLand was well able to reproduce observations with regard to area, temporal sequence, and spatial pattern of disturbance. The observed disturbance dynamics was strongly driven by interactions, with 64.3 % of the area disturbed attributed to interaction effects. A +4 °C warming increased the disturbed area by +264.7 % and the area-weighted mean patch size by +1794.3 %. Interactions were found to have a ten times higher sensitivity to temperature changes than main effects, considerably amplifying the climate sensitivity of the disturbance regime.Conclusions
Disturbance interactions are a key component of the forest disturbance regime. Neglecting interaction effects can lead to a substantial underestimation of the climate change sensitivity of disturbance regimes.15.
A tree diversity inventory was carried out in urban green spaces (UGSs) of Chennai metropolitan city, India. This inventory aims to study the diversity, density and richness of trees in UGSs of Chennai. A total of one hundred 10 m × 10 m (total 1 ha) plots were laid to reveal tree diversity and richness of UGSs. Trees with ≥10 cm girths at breast height (gbh) were inventoried. We recorded 45 species in 42 genera and 21 families. Caesalpiniaceae and Fabaceae each with 6 species dominated the study area followed by Arecaceae (3). Density and stand basal area of the present study were 500 stems ha?1 and 64.16 m2, respectively. Most of the inventoried trees were native (31 species) and deciduous (28 species). Fabaceae and Caesalpiniaceae dominated the present study area in terms of stand basal area and density. The Shannon diversity index and evenness of study area were 2.79 and 0.73, respectively. The most important species and families based on species important value index (IVI) and family important value index were Albizia saman, Polyalthia longifolia and Azadirachta indica; Fabaceae, Caesalpiniaceae and Annonaceae respectively. We find Chennai's urban forest is relatively superior to many urban forests of the world in terms of stand basal area and species richness. Results emphasize the importance of enhancement of urban green spaces in Chennai metropolitan city. 相似文献
16.
The aim of this study is to reveal the energy balance of walnut in Central Anatolian Region in Turkey. This study has been conducted at the walnut cultivating facilities during the 2014–2015 production season in K?r?ehir, Konya, Nev?ehir and Ni?de provinces of Central Anatolian Region in Turkey, where walnut cultivation is intense. In the study, a total of 28 walnut cultivation facilities, yielding walnut, have been selected through Neyman method and surveys and observations have been performed in these facilities. The agricultural input energies and output energies used in walnut cultivation have been calculated to define the energy use efficiency. According to the study findings, the energy inputs in walnut cultivation are calculated respectively 17,851.33?MJ ha?1 (74.40%) chemical fertilizer energy, 2229.87?MJ ha?1 (9.29%) fuel energy, 1640.64?MJ ha?1 (6.83%) irrigation water energy, 1539?MJ ha?1 (6.41%) machine energy, 508.02?MJ ha?1 (%2.11) chemical energy, 180.35?MJ ha?1 (0.75%) human labour energy and 43.33?MJ ha?1 (0.18%) farm manure energy. Production outputs have been calculated as 14,679.52?MJ ha?1. Following the energy calculations, the output/input ratio, specific energy, energy efficiency and net energy calculations have been calculated respectively as 0.61, 30.20?MJ kg?1, 0.03?kg MJ?1 and ?9313.02?MJ ha?1. Benefit-cost ratio was calculated as 1.88, by dividing the gross value of production by the total cost of production per hectare in walnut production. 相似文献
17.
In British Columbia, large-scale salvage harvesting has been underway to recover timber value from forest stands infested by mountain pine beetle during the current outbreak. Understanding the response of beetles to clearcut edges particularly at the landscape scale is crucial to understanding the impacts of increased habitat fragmentation due to salvage harvesting on the spread of the beetle infestations. A novel proximity analysis approach based on null models of complete spatial randomness with three different spatial extents was developed to examine the spatial patterns of infestations in relation to cutblocks. Inhomogeneous Poisson point process models were fitted to predict how intensities of infestations varied with distances to the nearest cutblocks. Marked Poisson point process models were also fitted to evaluate the effects of the variables associated with the nearest cutblocks and adjacent infested pine stands on the edge response of beetles. The results clearly illustrated a significant positive edge response of beetles at the landscape scale. The intensities of infestations decreased non-linearly with distances to the nearest cutblocks. The results also suggested that the quality and distribution of key habitat resources could not fully explain the fundamental mechanisms underlying the edge response. The behavioural change of beetle dispersal at edges may also be an important factor contributing to a positive edge response. The results from this study may be useful in improving the efficacy of mountain pine beetle management efforts. 相似文献
18.
In this study, energy use patterns and the functional relationship between energy inputs and output for pomegranate production were investigated in Antalya province in Turkey. It further objective to identify greenhouse gas (GHG) emissions in pomegranate production. Data were obtained from 75 farms using face-to-face interview method. The results indicated that 50,605.5?MJ ? ha?1 of total energy input was required for 76,252.3?MG ? ha?1 pomegranate energy output. 1.51 unit energy output was provided by using 1 unit energy input. 1 unit energy output and 1?kg pomegranate require 0.66 unit and 2.57?MJ energy input, respectively. The average CO2 emission amounts were also calculated to be 1.73?t CO2 per hectare and 88.1?kg CO2 per 1000?kg pomegranate production. Electricity, fertilizers and pesticides were the highest contributors to GHG emissions. Both total energy input usage and GHG emission amounts have been found to be decreasing as the farm size increases. Increasing scale of pomegranates orchards will not only increase energy efficiency and productivity but also decrease environmental pollution and damages. The regression analysis revealed that, excessive use of machinery and fuel inputs results in a decline in energy production in pomegranate. 相似文献
19.
Forest fragmentation, climate change and understory fire regimes on the Amazonian landscapes of the Xingu headwaters 总被引:1,自引:1,他引:0
Britaldo Soares-Filho Rafaella Silvestrini Daniel Nepstad Paulo Brando Hermann Rodrigues Ane Alencar Michael Coe Charton Locks Letícia Lima Letícia Hissa Claudia Stickler 《Landscape Ecology》2012,27(4):585-598
Understory fire modeling is a key tool to investigate the cornerstone concept of landscape ecology, i.e. how ecological processes relate to landscape structure and dynamics. Within this context, we developed FISC??a model that simulates fire ignition and spread and its effects on the forest carbon balance. FISC is dynamically coupled to a land-use change model to simulate fire regimes on the Amazonian landscapes of the Xingu Headwaters under deforestation, climate change, and land-use management scenarios. FISC incorporates a stochastic cellular automata approach to simulate fire spread across agricultural and forested lands. CARLUC, nested in FISC, simulates fuel dynamics, forest regrowth, and carbon emissions. Simulations of fire regimes under modeled scenarios revealed that the major current and future driver of understory fires is forest fragmentation rather than climate change. Fire intensity proved closely related to the landscape structure of the remaining forest. While climate change may increase the percentage of forest burned outside protected areas by 30% over the next four decades, deforestation alone may double it. Nevertheless, a scenario of forest recovery and better land-use management would abate fire intensity by 18% even in the face of climate change. Over this time period, the total carbon balance of the Xingu??s forests varies from an average net sink of 1.6?ton?ha?1?year?1 in the absence of climate change, fire and deforestation to a source of ?0.1?ton?ha?1?year?1 in a scenario that incorporates these three processes. 相似文献
20.
Fangyan Cheng Shiliang Liu Xiaoyun Hou Yueqiu Zhang Shikui Dong 《Landscape Ecology》2018,33(5):783-798