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1.
This study analyzed structures of natural riparian forests and explored planning models applicable to establishing riparian greenways. Twenty-one streams or valleys were selected considering watersheds and climate regions of four major rivers in South Korea. The study surveyed mature structures and growth environments of the forests typical of the study streams in 122 sample plots. Forest communities associated with environmental gradients from floodplains to uplands were typified based on importance values of woody plant species and classification criteria of forest types in the country. The riparian forests were classified into 6–12 community types for each river watershed. The majority of dominant community tree species were distributed widely over the study streams, but some tree species were dominant in community types found in warmer regions only. This study presented planning models for restoring riparian greenways that reflect the distinct structural characteristics of the native community types. The planning models included species selection and composition, density and distance, and soil properties for tree plantings by community type, as well as a minimum width for riparian greenways. The models emphasized highly diverse ecological planting to enhance the multiple functions of riparian greenways, and establish native landscapes earlier through direct tree plantings rather than natural succession. A case study greenway was designed and planted to illustrate application of the planning model. 相似文献
2.
Naoki Kabeya Akira Shimizu Tatsuhiko Nobuhiro Koji Tamai 《Paddy and Water Environment》2008,6(1):25-35
To elucidate the water cycle in lowland forests of the Mekong River basin, our research group established four experimental
watersheds in the Stung Chinit River basin in Kampong Thom Province, Cambodia. The drainage areas of these experimental watersheds
ranged from small (4 km2) to mesoscale (3,659 km2). Here, we present the first preliminary results of our rainfall-discharge observations and analyses of temporal variations
of stable isotope ratios in rainfall, stream water, and groundwater. This paper focuses on the following three main topics:
annual rainfall, discharge, and water balance; stormflow generation and dominant flow pathways; and flow regimes and stream
water residence times. All stream water residence times (τ = 1.7–7.5 months) for the four experimental watersheds were shorter than the residence time of the groundwater (τ = 9.4 months) through the soil and regolith layers, implying that the stream waters consisted of not only the groundwater-flow
component, but also younger-aged flow components such as saturation-excess overland flow. The smallest (4 km2; O Toek Loork) watershed had longer residence time (τ = 7.5 months) than the three larger watersheds (126–3,659 km2; τ = 1.7–3.9 months). This may suggest differing contributions of the groundwater and younger-aged flow components in the stream
water in each watershed. Our approach of multi-scale watershed observation might better contribute to the needs of physically
based models and aid in predictions for ungauged basins. 相似文献
3.
The purpose of this study was to analyze the propriety of establishing riparian greenspace for watersheds of four major rivers in South Korea and suggest strategies for improving the analyzed problems. Growth environments, vegetation structures, planting techniques, and tree growth and management conditions were analyzed targeting 45 sites. Soils at the sites had organic matter of 1.3 % and cation exchange capacity of 4.4 cmol+/kg, which are poor conditions for tree growth. A tree diameter at breast height of <7 cm accounted for 77 % of all trees planted, and mean tree cover was only 28 % due to planting of mainly small trees. Planting techniques were represented by single-layered planting (84 %) consisting of a single species or a few species in similar size. Approximately 11 % of all planted trees withered, and many trees had poor growth. The growth ratios for shoot and leaf length in planted trees compared with normally growing trees were 57 and 77 %, respectively. Oppression by invasion of herbaceous and climbing plants associated with negligent maintenance hindered normal tree growth at some sites. Strategies to improve these problems and promote the function of riparian greenspaces suggest securing a minimum width and connectivity of greenspace, analyzing growth ground prior to planting, improving the soil environment, woodchip mulching on ground surfaces, middle/high density plantings mixed with fast-growing trees, edge planting to protect internal growth environment, and multilayered and grouped ecological planting reflecting natural riparian forest structures. 相似文献
4.
Background
Recent studies of anadromous salmon (Oncorhynchus spp.) on the Pacific Coast of North America indicate an important and previously unrecognized role of salmonid nutrients to terrestrial biota. However, the extent of this uptake by primary producers and consumers and the influences on community structure remain poorly described. We examine here the contribution of salmon nutrients to multiple taxa of riparian vegetation (Blechnum spicant, Menziesii ferruginea, Oplopanax horridus, Rubus spectabilis, Vaccinium alaskaense, V. parvifolium, Tsuga heterophylla) and measure foliar δ15N, total %N and plant community structure at two geographically separated watersheds in coastal British Columbia. To reduce potentially confounding effects of precipitation, substrate and other abiotic variables, we made comparisons across a sharp ecological boundary of salmon density that resulted from a waterfall barrier to salmon migration.Results
δ15N and %N in foliage, and %cover of soil nitrogen indicators differed across the waterfall barrier to salmon at each watershed. δ15N values were enriched by 1.4‰ to 9.0‰ below the falls depending on species and watershed, providing a relative contribution of marine-derived nitrogen (MDN) to vegetation of 10% to 60%. %N in foliar tissues was slightly higher below the falls, with the majority of variance occurring between vegetation species. Community structure also differed with higher incidence of nitrogen-rich soil indicator species below the waterfalls.Conclusions
Measures of δ15N, %N and vegetation cover indicate a consistent difference in the riparian community across a sharp ecological boundary of salmon density. The additional N source that salmon provide to nitrogen-limited habitats appears to have significant impacts on the N budget of riparian vegetation, which may increase primary productivity, and result in community shifts between sites with and without salmon access. This, in turn, may have cascading ecosystem effects in forests adjacent to salmon streams.5.
海南岛作为中国仅有的两大热区之一,森林资源极其丰富,具有非常重要的生态和经济价值。本世纪以来,海南省的经济一直呈高速增长态势,橡胶林作为当地森林的重要组成部分,其种植面积因全球胶价的快速攀升增加了约50%,经济的快速发展和橡胶等人工林的增长将对森林的结构和分布产生重要影响,在此背景下监测森林现状及动态变化可为海南岛森林可持续经营管理和国家生态文明试验区建设提供重要依据。本文联合Landsat/Sentinel-2光学和PALSAR/PALSAR-2雷达多源遥感影像为数据源,以海南岛为研究对象,基于谷歌地球引擎（Google Earth Engine, GEE）监测海南岛2007—2018年的森林变化特征。研究结果表明：（1）2007—2018年海南岛森林面积增长显著,从2007年的1.94×104 km2增长至2018年的2.15×104 km2,覆盖率从56.43%上升到62.59%,森林面积年平均增长率为0.99%;（2）2007—2018年,在海南岛18个市（县）中有15个市（县）的森林面积呈正增长趋势,其中增长排前5的市（县）（儋州市、澄迈县、琼海市、临高县、定安县）增长面积占正增长市（县）总增长面积的68.78%,仅有东方市、三亚市和琼中县3个市（县）的森林面积有所下降,分别下降了13、76、113 km2;（3）森林增长集中分布在海拔小于200 m和坡度小于8°的区域,分别占增长总面积的92.88%和91.43%;（4）橡胶林的增长是森林面积快速增长的主要原因,橡胶林面积增长最多的5个市（县）其森林面积也增长最多,这5个市（县）的橡胶增长总面积占森林总增长面积的63.40%;（5）森林损失区域集中在海南岛南部、西南部和东北部沿海地区,主要是因为高郁闭度森林（如橡胶林）逐步转换为郁闭度较底的热带果园（如芒果园等）,另外旅游建设开发、城市化和水利建设等也导致了部分森林损失。研究总体显示,海南岛2007—2018年森林在低海拔平缓区域增长显著,森林消长具有一定的空间差异性,中部山区森林持续保持较高的覆盖度且较少大面积森林损失,总体增长模式良好。 相似文献
6.
Backround
P. avium, a pioneer tree species that colonizes early forest successional stages, is assumed to require an effective strategy allowing stably repeatable rounds of local establishment, dispersal and local extinction. Consequently, the early replacement of cherry by climax tree species makes the establishment of several local generations very unlikely, especially in central European continuous cover forests. This has to be seen in connection with the mixed reproduction system involving asexual reproduction as a complementary adaptational strategy. Tests of the local establishment of wild cherry must therefore consider the possibility of first generation establishment via seedling recruitment potentially followed by an asexual generation (root suckering). Successful establishment can therefore be determined only among adult individuals with the option of detecting vegetative reproduction at these stages. To test the implied suggestion about local establishment strategies of wild cherry, nuclear microsatellites were used to analyse patterns of asexual propagation among adult stages that have been subjected to one of two major types of forest management. These management types, the historical "coppice with standards system" (CWS) and the "high forest system" (HFS), can be reasonably assumed to have affected the reproduction system of P. avium. 相似文献7.
Background
Bi-directional flow of nutrients between marine and terrestrial ecosystems can provide essential resources that structure communities in transitional habitats. On the Pacific coast of North America, anadromous salmon (Oncorhynchus spp.) constitute a dominant nutrient subsidy to aquatic habitats and riparian vegetation, although the contribution to terrestrial habitats is not well established. We use a dual isotope approach of δ15N and δ13C to test for the contribution of salmon nutrients to multiple trophic levels of litter-based terrestrial invertebrates below and above waterfalls that act as a barrier to salmon migration on two watersheds in coastal British Columbia. 相似文献8.
Shereif H. Mahmoud J. Adamowski A. A. Alazba A. M. El-Gindy 《Paddy and Water Environment》2016,14(1):231-246
Human activities, which affect ecosystem dynamics, pose a continuous challenge to individuals and communities trying to survive in arid and semi-arid regions. The development of a method to employ rainwater harvesting (RWH) in the management of agricultural drought in arid and semi-arid regions comprised two phases: (i) detection of agricultural drought in Egypt’s El-Beheira governorate using a normalized difference vegetation index differencing technique and (ii) the delineation of RWH locations potentially suitable for the management of agricultural drought in the region using a GIS decision support system (DSS). Temporal vegetation cover analysis showed significant spatio-temporal changes that have occurred in the last 40 years: a general decrease in vegetation cover reflecting a trend towards ecosystem degradation, contrasted by a greening trend in some pockets within the region. Potentially suitable rainwater harvesting areas for agricultural drought management and attendant vegetation recovery were delineated in the region using DSS. The model generated a RWH map with five categories of suitability: excellent, good, moderate, poor and unsuitable. On average, 10.9 % (1104.17 km2) and 12 % (1215 km2) of the study area was classified as excellent and good for RWH, respectively, while 11.7 % (1185.21 km2), 15.4 % (1560 km2) and 50 % (5065 km2) of the area were classified as moderate, unsuitable and poor, respectively. Most of the areas with excellent to good suitability predominantly lie in areas which faced severe drought between 2010 and 2014. To successfully implement the drought management plan, a number of RWH sites within the excellent areas must be developed. 相似文献
9.
The Total Maximum Daily Load (TMDL) program is an integrated process of watershed assessment and management to address surface
water quality impairment. The management of organic contaminants and nutrients is a primary concern in conserving surface
water bodies. Watershed-scale pollutant loads simulation can assist stakeholders and watershed planners in making decisions
on immediate and long-term land use schemes to improve water quality. However, the behavior of contaminants in a watershed
needs to be characterized prior to such model applications. The objectives of this study were to characterize point and nonpoint
pollutants runoff at a watershed scale and to develop a Pollutant Load Calculation Model (PLCM), which facilitates the estimation
of pollutant delivery to a watershed outlet. The developed model was applied for the six sub-watersheds of the Saemangeum
estuarine watershed in Korea, where a large tidal reclamation project has been underway. Two years stream flow and water quality
data were used for the model calibration, while 1 year data were utilized for the model validation. The model calibration
resulted in the R
2 values of 0.58, 0.53, and 0.35 for BOD, TN, and TP, respectively. Overall performance for the validation period was similar
with that for the calibration period although the R
2 values were slightly decreased. The PLCM tends to substantially under or overestimate delivery pollutants loads during the
summer rainy seasons when most rainfall events occur. This is probably because once-a-month-measured water quality data, which
might not represent appropriately monthly water quality, particularly, for rainy seasons, were used for the loads calculation.
Thus, more frequently monitored water quality data should be used for the delivery loads estimation at least for a rainy season
in order to improve the PLCM performance. Nevertheless, the developed model took the pollutant reduction process into account,
which is not allowed with the conventional unit loading method, and furthermore temporal variations of pollutant loads based
on stream flows were also incorporated into the pollutant loads estimation. The developed PLCM can be a useful tool to assess
pollutants delivery loads at a watershed scale and thus assist decision makers in developing watershed pollution management
schemes. 相似文献
10.
Background
The Brazilian Atlantic Forest is highly endangered and only about 7% of the original forest remains, most of which consists of fragments of secondary forest. Small mammals in the Atlantic Forest have differential responses to this process of fragmentation and conversion of forest into anthropogenic habitats, and have varying abilities to occupy the surrounding altered habitats. We investigated the influence of vegetation structure on the micro-scale distribution of five small mammal species in six secondary forest remnants in a landscape of fragmented Atlantic Forest. We tested whether the occurrence of small mammal species is influenced by vegetation structure, aiming to ascertain whether species with different degrees of vulnerability to forest fragmentation (not vulnerable: A. montensis, O. nigripes and G. microtarsus; vulnerable: M. incanus and D. sublineatus; classification of vulnerability was based on the results of previous studies) are associated with distinct vegetation characteristics. 相似文献11.
Lee Ji Min Park Youn Shik Kum Donghyuk Jung Younghun Kim Bomchul Hwang Soon Jin Kim Hyun Bae Kim Chulgoo Lim Kyoung Jae 《Paddy and Water Environment》2014,12(1):169-183
Aquatic ecosystems are threatened by increasing variability in the hydrologic responses. In particular, the health of river ecosystems in steeply sloping watersheds is aggravated due to soil erosion and stream depletion during dry periods. This study suggested and assessed a method to improve the adaptation ability of a river system in a steep watershed. For this, this study calibrated soil and water assessment tool (SWAT) for runoff and sediment, and quantified the changes in hydrologic responses such as groundwater recharge rate soil erosion and baseflow according to two scenarios for adjustment of the watershed slope (steep to mild). Here, one scenario was set by three measured slopes, and the other was set by fixing the entire watershed slopes with 5 %. Moreover, SWAT and web-based hydrograph analysis tool (WHAT) models were applied to estimate groundwater recharge, soil erosion, and baseflow in the Haean-myeon watershed in South Korea. The results show that the reduction of watershed slope increased groundwater recharge and baseflow, and decreased sediment. Specifically, groundwater recharge rate was increased from 257.10 to 364.60 mm, baseflow was increased from 0.86 to 1.19 m3/s, and sediment was decreased from 194.6 to 58.1 kg/km2. Based on these results, the suggested method will positively contribute to aquatic ecosystems and farming environments in a steeply sloping watershed due to improvements in the quantity and quality of river water. 相似文献
12.
Junichiro Takeuchi Chie Imagawa Toshihiko Kawachi Koichi Unami Shigeya Maeda Tomoki Izumi 《Paddy and Water Environment》2010,8(2):175-187
A distributed hydro-environmental model is developed that achieves detailed analysis of the movement of water at a field-plot-scale
resolution in a mesoscale watershed including lowland areas where, especially for agricultures, it is an essential need to
get rid of redundant groundwater by drainage facilities such as rivers, canals and/or underdrains. For this, the problem geometry
is meshed with unstructured cells of triangular shape. Profile of a column cell is zoned into two: surface zone and groundwater
zone in which water movement is represented by combined tank and soil moisture sub-models, and well-defined two-dimensional
unconfined shallow groundwater flow sub-model, respectively. The top-two sub-models serve to evaluate evapotranspiration,
infiltration, soil water content, lateral surface water flow, and vertical percolation. The vertical percolation so evaluated
is given as longitudinal recharge to the bottom sub-model for computing groundwater flow. Surface water–groundwater interactions
through beds and stream-banks of perennial and ephemeral canals are considered by treating the canal courses as internal boundaries
in the groundwater flow model. The finite volume method (FVM) that allows of unstructured mesh and produces conservative solutions
is employed for groundwater flow computation. The model developed is applied to an actual watershed which includes a low-lying
paddy area to quantify the hydrological impact of land-use management practices over a period of 29 years in which the farmland
consolidation project was implemented and part of the paddy fields were converted to upland crop fields and housing lands.
From the results obtained, it is concluded that the model presently developed lends itself to water—as well as land-use management
practices. 相似文献
13.
Evaluation of MODIS NDVI and LST for indicating soil moisture of forest areas based on SWAT modeling
Park Jong-Yoon Ahn So-Ra Hwang Soon-Jin Jang Cheol-Hee Park Geun-Ae Kim Seong-Joon 《Paddy and Water Environment》2014,12(1):77-88
This study examined the capability of remotely sensed information gained using the terra moderate resolution imaging spectroradiometer (MODIS) normalized difference vegetation index (NDVI) and land surface temperature (LST) to explain forest soil moisture. The soil and water assessment tool (SWAT) was used for the analysis. Nine years (2000–2008) of monthly MODIS NDVI and LST data from a 2,694.4 km2 watershed consisting of forest-dominant areas in South Korea were compared with SWAT simulated soil moisture. Before the analysis, the SWAT model was calibrated and verified using 9 years of daily streamflow at three gauging stations and 6 years (2003–2008) of daily measured soil moisture at three locations within the watershed. The average Nash–Sutcliffe model efficiency during the streamflow calibration and validation was 0.72 and 0.70, respectively. The SWAT soil moisture showed a higher correlation with MODIS LST during the forest leaf growing period (March–June) and with MODIS NDVI during the leaf falling period (September–December). Low correlation was observed in the year of frequent rains, regardless of the leaf periods. 相似文献
14.
Chie Imagawa Junichiro Takeuchi Toshihiko Kawachi Kei Ishida Shunsuke Chono Natsuki Buma 《Paddy and Water Environment》2011,9(4):425-439
Long-term simulation using the distributed hydro-environmental watershed model is efficacious for assessing irrigation impacts
on hydrological cycle in detail and for implementing watershed management successfully. In this article, the previously developed
hydro-environmental watershed model (HEWM-1) is improved in the water exchange process caused by surface water-groundwater
interaction via drainage canals and/or underdrains. The time-varying stream flow in canals is described by the complete one-dimensional
shallow water equations in a newly introduced submodel, the open channel flow submodel. This submodel coordinates with the
other submodels: the tank, soil moisture and groundwater flow submodels which are interlinked in a cascade manner. The improved
model (HEWM-2) is applied to an agricultural watershed covering an area from an alluvial fan onto a nearly level alluvial
plain, to be validated. The simulation by HEWM-2 is informative for identifying whether any drainage canal is gaining or losing
water in relation to groundwater level. It could thus provide useful information for conserving a complex network of drainage
canals which also functions as a passage for aquatic animals like fishes. 相似文献
15.
A process model for explaining genotypic and environmental variation in growth and yield of rice based on measured plant N accumulation 总被引：2，自引：0，他引：2
The objective of this study was to develop a mechanistic model for simulating the genotypic and environmental variation in rice growth and yield based on measured plant N accumulation. The model calibrations and evaluations were conducted for rice growth and yield data obtained from a cross-locational experiment on 9 genotypes at 7 climatically different locations in Asia. The rough dry grain yield measured in the experiment ranged from 71 to 1044 g m−2 over the genotypes and locations. An entire process model was developed by integrating sub-models for simulating the processes of leaf area index development, partitioning of nitrogen within plant organs, vegetative biomass growth, spikelet number determination, and yield. The entire process model considered down-regulation of photosynthesis caused by limited capacity for end-product utilization in growing sink organs by representing canopy photosynthetic rate as a function of sugar content per unit leaf nitrogen content. The model well explained the observed genotypic and environmental variation in the dynamics of above-ground biomass growth (for validation dataset, R2 = 95), leaf area index development (R2 = 0.82) and leaf N content (R2 = 0.85), and spikelet number per unit area (R2 = 0.67) and rough grain yield (R2 = 0.66), simultaneously. The model calibrations for each sub-model and the entire process model against observed data identified 10 genotype-specific model parameters as important traits for determining genotypic differences in the growth attributes. Out of the 10 parameters, 5 were related to the processes of phenological development and spikelet sterility, considered to be major determinants of genotypic adaptability to climate. The other 5 parameters of stomatal conductance, radiation extinction coefficient, nitrogen use efficiency in spikelet differentiation, critical leaf N causing senescence, and potential single grain mass had significant influence on the yield potential of genotypes under given climate conditions. 相似文献
16.
Citrus black spot disease is caused by Guignardia citricarpa and has a global distribution range that is restricted to some regions with summer rainfall and is absent from winter rainfall regions. Some countries restrict the import of fresh citrus fruit from countries where G. citricarpa occurs. A CLIMEX model was previously used to predict the climatic suitability of Europe for potential establishment of the organism, but the European Food Safety Authority criticised aspects of that study. Distributions in South Africa, Australia and Taiwan were used to develop a new set of parameter values that provide a better fit to the known distribution of G. citricarpa and provide confidence that the model is a distinct improvement over that of previous modelling efforts. The new CLIMEX model correctly reflects climatic suitability of all regions in the world where the organism is known to occur. The model indicates that most of Europe is completely unsuitable for the establishment of G. citricarpa. Within European citrus producing regions, suitable areas are highly constrained, never more than marginally suitable, and all have lower levels of suitability than any area in South Africa and Australia where G. citricarpa is known to occur. It is concluded that the potential risk of G. citricarpa establishment in these regions is exceedingly low. 相似文献
17.
Jin-Ah Kim Sang-Woo Lee Gil-Soon Hwang Soon-Jin Hwang Chulgoo Kim Kyung-Jin An 《Paddy and Water Environment》2016,14(2):299-312
Urban land use can adversely affect the water quality of adjacent streams through interactions at the edges of the two ecosystems. From a landscape ecological perspective, edges control the flow rate of materials between two adjacent systems. Based on the rationale that the streamline complexity formed between land uses and water bodies may function in this manner, we investigated the potential role of streamline complexity in the relationship between stream ecological communities and urban land use in Korea. Various indices of biological indicators including the diatom assemblage index for organic pollution, the trophic diatom index, the Korean saprobic index, and the index of biotic integrity were applied at 80 sampling sites in the Nakdong River system. We computed the fractal dimensions of the streamlines within 1-km buffers and the proportion of urban land use in the watershed within 5-km buffers around the sampling sites. A moderation model was adopted to investigate the role of streamline complexity in the relationship between urban land use and the biological indices of ecological communities. A comparison between a simple geometry regression model and complex geometry models indicated that streamline complexity may moderate the adverse impacts of urban land use on ecological communities in streams. The moderating effect of streamline complexity was particularly significant for assemblages of macroinvertebrates and fishes. Therefore, to enhance the ecological integrity of streams, we strongly recommend considering streamline complexity when restoring channelized streams in developed areas. 相似文献
18.
Jonas Glatthorn Eike Feldmann Vath Tabaku Christoph Leuschner Peter Meyer 《BMC ecology》2018,18(1):47
Background
Old-growth and primeval forests are passing through a natural development cycle with recurring stages of forest development. Several methods for assigning patches of different structure and size to forest development stages or phases do exist. All currently existing classification methods have in common that a priori assumptions about the characteristics of certain stand structural attributes such as deadwood amount are made. We tested the hypothesis that multivariate datasets of primeval beech forest stand structure possess an inherent, aggregated configuration of data points with individual clusters representing forest development stages. From two completely mapped primeval beech forests in Albania, seven ecologically important stand structural attributes characterizing stand density, regeneration, stem diameter variation and amount of deadwood are derived at 8216 and 9666 virtual sampling points (moving window, focal filtering). K-means clustering is used to detect clusters in the datasets (number of clusters (k) between 2 and 5). The quality of the single clustering solutions is analyzed with average silhouette width as a measure for clustering quality. In a sensitivity analysis, clustering is done with datasets of four different spatial scales of observation (200, 500, 1000 and 1500 m2, circular virtual plot area around sampling points) and with two different kernels (equal weighting of all objects within a plot vs. weighting by distance to the virtual plot center).Results
The clustering solutions succeeded in detecting and mapping areas with homogeneous stand structure. The areas had extensions of more than 200 m2, but differences between clusters were very small with average silhouette widths of less than 0.28. The obtained datasets had a homogeneous configuration with only very weak trends for clustering.Conclusions
Our results imply that forest development takes place on a continuous scale and that discrimination between development stages in primeval beech forests is splitting continuous datasets at selected thresholds. For the analysis of the forest development cycle, direct quantification of relevant structural features or processes might be more appropriate than classification. If, however, the study design demands classification, our results can justify the application of conventional forest development stage classification schemes rather than clustering.19.
T.D. Setiyono A. Weiss J.E. Specht K.G. Cassman A. Dobermann 《Field Crops Research》2008,108(1):82-92
Different approaches have been used to simulate leaf area index (LAI) in soybean (Glycine max L. Merr). Many of these approaches require genotype-specific calibration procedures. Studies modeling LAI dynamics under optimal growth conditions with yields close to the yield potential of soybean have remained scarce. A sink-driven approach was developed and evaluated for LAI simulation in soybean under near-optimal environments. The rate of change in expanding leaf area was simulated using the first derivative of a logistic function accounting for plant population density, air temperature, and water deficit. The rate of change in senescing leaf area was also simulated using the first derivative of a logistic function, assuming monocarpic senescence that began at the flowering stage (R1). Phenology was simulated as a function of temperature and photoperiod. Data for model development and evaluation were obtained from irrigated field experiments conducted at two locations in Nebraska, where agronomic management was optimized to achieve growth at a near yield potential level. LAI simulation with the proposed model had average RMSE of 0.52 m2 m−2 for independent data at the two locations. The proposed model has minimum input requirements. Interactions between leaf growth and source-driven processes can be incorporated in the future, while maintaining the basic physiological assumptions underlining leaf expansion and senescence. 相似文献
20.
Jennifer J Swenson Bruce E Young Stephan Beck Pat Comer Jesús H Córdova Jessica Dyson Dirk Embert Filomeno Encarnación Wanderley Ferreira Irma Franke Dennis Grossman Pilar Hernandez Sebastian K Herzog Carmen Josse Gonzalo Navarro Víctor Pacheco Bruce A Stein Martín Timaná Antonio Tovar Carolina Tovar Julieta Vargas Carlos M Zambrana-Torrelio 《BMC ecology》2012,12(1):1-19