Cultivated floodplains of the Cambodian Mekong delta: understanding the changing balance between the flow regime and the agricultural practices

2021 ◽  
Author(s):  
Christina Anna Orieschnig ◽  
Gilles Belaud ◽  
Jean-Philippe Venot ◽  
Sylvain Massuel
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Changes ◽  
Local Population ◽  
Agricultural Productivity ◽  
Mekong Delta ◽  
Agricultural Practices ◽  
Fruit Trees ◽  
Climate Change Scenarios ◽  
Crop Water

<p>On the floodplains of the Cambodian Mekong Delta, rainfed and irrigated dry-season agriculture is a crucial source of revenue for the local population. Traditional rice production is being progressively complemented by the cultivation of higher-value crops like maize, fruit trees and vegetables. Fundamentally, the annual monsoon regime and the resulting flood dynamics determine the framework for these agricultural practices, with a wet season lasting from June to November and a peak high flow reached in September. Rice is cultivated after flood recession in lower-lying areas. On higher terrain, fruit trees and vegetables are widely irrigated by farmers using individual pumps to lift water from large-scale communal channels.</p><p><br>However, in recent years, various drivers of change have impacted these long-established dynamics. Climate change is causing shifting precipitation patterns and a modification of annual flow regimes in the Mekong river and its deltaic distributaries. In addition, the irrigation channel infrastructure is being largely rehabilitated by both local initiatives and international development agencies. These measures are rapidly changing the conveyance network for inundation, drainage, and irrigation on the floodplains, with proportions and consequences which are yet unknown. Finally, land use changes driven by market forces - such as the shift to cash crops like mango trees - are modifying the crop water demand in the area. </p><p><br>In this context, the present study aims to provide a thorough understanding and quantification of the effects of these changes with regard to crop water requirements, irrigation efficiency, and agricultural productivity. Extensive fieldwork was carried out on a 44-km² area to gather knowledge of agricultural practices (especially irrigation) and to identify the main local hydrological objects and drivers. The land use and seasonal inundation extents were characterized through remote sensing analyses, using optical Sentinel-2 and synthetic aperture radar (SAR) Sentinel-1 images. On that basis, an eco-hydrological model is being developed on the generic software platform OpenFLUID, explicitly representing the hydraulic connections and irrigation decisions. This tool will be used to highlight possible salient control factors for hydrological processes, and to simulate the direct and indirect effects of climate change scenarios, irrigation and water power infrastructure development, and land use changes on local hydrology, irrigation, and agricultural productivity. </p>

scholarly journals Modeling the combined impact of future climate and land use changes on streamflow of Xinjiang Basin, China

2015 ◽  
Vol 47 (2) ◽  
pp. 356-372 ◽  
Author(s):  
Renhua Yan ◽  
Jiacong Huang ◽  
Yan Wang ◽  
Junfeng Gao ◽  
Lingyan Qi
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Planning ◽  
Scientific Information ◽  
Land Use Changes ◽  
Coupled Model ◽  
Climate Scenario ◽  
Future Climate ◽  
Climate Change Scenarios ◽  
Future Evolution

The response of hydrologic circulation to climate and land use changes is important in studying the historical, present, and future evolution of aquatic ecosystems. In this study, the Coupled Model Inter-comparison Project Phase 5 multi-model ensemble and a raster-based Xin'anjiang model were applied to simulate future streamflows under three climate change scenarios and two land use/cover change conditions in the Xinjiang Basin, China, and to investigate the combined effect of future climate and land use/cover changes on streamflow. Simulation results indicated that future climate and land use/cover changes affect not only the seasonal distributions of streamflow, but also the annual amounts of streamflow. For each climate scenario, the average monthly streamflows increase by more than 4% in autumn and early winter, while decreasing by more than −26% in spring and summer for the 21st century. The annual streamflows present a clear decreasing trend of −27%. Compared with land use/cover change, climate change affects streamflow change more. Land use/cover change can mitigate the climate change effect from January to August and enhance it in other months. These results can provide scientific information for regional water resources management and land use planning in the future.

scholarly journals Agricultural and Forestry Land and Labor Use under Long-Term Climate Change in Chile

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 305
Author(s):  
Oscar Melo ◽  
William Foster
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Climate Changes ◽  
Land Use Changes ◽  
Climate Change Scenarios ◽  
Income Generation ◽  
Net Income ◽  
Average Output ◽  
Allocation Model ◽  
Municipal Level

The appropriate design of land-use and rural employment policies depends upon the anticipated performance of the farm sector in the context of expected climate changes, especially with respect to land allocations to potential activities. Concerns over the possible net benefits of land-use changes are particularly acute in lower- and middle-income countries, where agriculture tends to be important in employment, income generation and foreign-exchange earnings. This paper presents an analysis of the expected impacts on land use in Chile of projected climate-change scenarios in 2040 and 2070. We developed a farmland allocation model with associated labor employment at the municipal level driven by expected relative net incomes per hectare, constructed from local average per-hectare yields, regional average output prices and per-hectare production cost estimates. The sensitivities of cropland allocations to relative net-income changes were estimated using historical land allocations at the municipal level derived from the last two Chilean Agricultural Censuses. The results show that the impacts of climate changes will be mitigated by land-use adaptation, the main export-earning crops tending to move south; in aggregate, agricultural employment will decrease in all the climate-change scenarios; forestry and agriculture would likely suffer a loss in net-income generation under severe climate-change scenarios.

scholarly journals Scenario-based impacts of land use and climate changes on the hydrology of a lowland rainforest catchment in Ghana, West Africa

2017 ◽  
Author(s):  
Michael S. Aduah ◽  
Graham P. W. Jewitt ◽  
Michele L. W. Toucher
Keyword(s):  
Climate Change ◽  
Land Use ◽  
West Africa ◽  
Spatial Variability ◽  
Climate Changes ◽  
Land Use Changes ◽  
Control Period ◽  
Mitigation Strategies ◽  
Climate Change Scenarios ◽  
Land Use Scenarios

Abstract. This study analysed the separate and the combined impacts of climate and land use changes on hydrology on the Bonsa catchment in Ghana, West Africa, using the ACRU hydrological model. The study used five RCP8.5 climate change scenarios (wet, 25th percentile, 75th percentile, dry and a multi-model median of nine GCMs) from the CMIP5 AR5 models for near (2020–2039) and far (2060–2079) future time slices. Change factors were used to downscale the GCM scenarios to the local scale, using observed climate data for the control period of 1990 to 2009. The land use of 1991 and 2011 were used as the baseline and current land use as well as three future land use scenarios (BAU, EG, EGR) for two time slices (2030 and 2070) were used. The study showed that under all separate climate change scenarios, overall flows reduced, but under combined climate and land use changes, streamflows increased. Under the combined scenarios, streamflow responses due to the different future land use scenarios were not substantially different. Also, land use is the dominant controlling factor in streamflow changes in the Bonsa catchment under a dry climate change, but under a wet climate change, climate controls streamflow changes. The spatial variability of catchment streamflow changes under combined land use and climate changes were greater than the spatial variability of streamflow changes under climate change. The range of plausible future streamflows changes derived in this study provides natural resources and environmental managers of the Bonsa catchment, the first ever and the most current information to develop suitable adaptation and mitigation strategies, to prepare adequately for climate and land use changes.

scholarly journals Major United States Land Use as Influenced by an Altering Climate: A Spatial Econometric Approach

Land ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 546
Author(s):  
Sung-Ju Cho ◽  
Bruce McCarl
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Changes ◽  
Climate Change Scenarios ◽  
Spatial Effects ◽  
Pasture Grass ◽  
Temperature And Precipitation ◽  
Econometric Approach ◽  
Business As Usual ◽  
The U.S

Climate and socioeconomic and policy factors are found to stimulate land use changes along with changes in greenhouse gas emissions and adaption behaviors. Most of the studies investigating land use changes in the U.S. have not considered potential spatial effects explicitly. We used a two-step linearized multinomial logit to examine the impacts of various factors on conterminous U.S. land use changes including spatial lag coefficients. The estimation results show that the spatial dependences have existed for cropland, pastureland, and grasslands with a negative dependence on forests but weakened in most of the land uses except for croplands. Temperature and precipitation were found to have nonlinear impacts on the land use shares in the succeeding years by exerting opposite effects on crop versus pasture/grass shares. We also predicted land use changes under different climate change scenarios. The simulation results imply that the southern regions of the U.S. would lose cropland shares with further severity under the business-as-usual climate scenarios, while the land use shares for pasture/grass and forest would increase in those regions. As land use plays an important role in the climate system and vice versa, the results from this study may help policymakers tackle climate-driven land use changes and farmers adapt to climate change.

Modeling impacts of climate and land use change on streamflow, nitrate, and ammonium in the Kor River, southwest of Iran

2018 ◽  
Vol 10 (4) ◽  
pp. 818-834 ◽  
Author(s):  
Amir Asadi Vaighan ◽  
Nasser Talebbeydokhti ◽  
Alireza Massah Bavani ◽  
Paul Whitehead
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Changes ◽  
Climate Change Scenarios ◽  
Future Period ◽  
Intergovernmental Panel ◽  
Assessment Report ◽  
Kor River ◽  
Southwest Of Iran ◽  
Catchment Model

Abstract This study examined the separate and combined impacts of future changes in climate and land use on streamflow, nitrate and ammonium in the Kor River Basin, southwest of Iran, using the representative concentration pathway 2.6 and 8.5 scenarios of the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC). Different land use and climate change scenarios were used and the streamflow, nitrate and ammonium in the future period (2020–2049) under these scenarios were simulated by Integrated Catchment Model for Nitrogen (INCA–N). Results indicated that climate change will increase streamflows and decrease nitrate and ammonium concentrations in summer and autumn. Land use changes were found to have a little impact on streamflows but a significant impact on water quality, particularly under an urban development scenario. Under combined scenarios, larger seasonal changes in streamflows and mixed changes of nitrate and ammonium concentrations were predicted.

scholarly journals A modeling approach to determine the impacts of land use and climate change scenarios on the water flux of the upper Mara River

2010 ◽  
Vol 7 (4) ◽  
pp. 5851-5893 ◽  
Author(s):  
L. M. Mango ◽  
A. M. Melesse ◽  
M. E. McClain ◽  
D. Gann ◽  
S. G. Setegn
Keyword(s):  
Climate Change ◽  
Water Quality ◽  
Land Use ◽  
Land Use Change ◽  
Water Balance ◽  
Air Temperature ◽  
Land Use Changes ◽  
Water Flux ◽  
Climate Change Scenarios ◽  
Water Balance Components

Abstract. With the flow of the Mara River becoming increasingly erratic especially in the upper reaches, attention has been directed to land use change as the major cause of this problem. The semi-distributed hydrological model Soil and Water Assessment Tool (SWAT) and Landsat imagery were utilized in the upper Mara River Basin in order to 1) map existing field scale land use practices in order to determine their impact 2) determine the impacts of land use change on water flux; and 3) determine the impacts of rainfall (0%, ±10% and ±20%) and air temperature variations (0% and +5%) based on the Intergovernmental Panel on Climate Change projections on the water flux of the upper Mara River. This study found that the different scenarios impacted on the water balance components differently. Land use changes resulted in a slightly more erratic discharge while rainfall and air temperature changes had a more predictable impact on the discharge and water balance components. These findings demonstrate that the model results show the flow was more sensitive to the rainfall changes than land use changes. It was also shown that land use changes can reduce dry season flow which is the most important problem in the basin. The model shows also deforestation in the Mau Forest increased the peak flows which can also lead to high sediment loading in the Mara River. The effect of the land use and climate change scenarios on the sediment and water quality of the river needs a thorough understanding of the sediment transport processes in addition to observed sediment and water quality data for validation of modeling results.

scholarly journals Changes in Coastal Agricultural Land Use in Response to Climate Change: An Assessment Using Satellite Remote Sensing and Household Survey Data in Tien Hai District, Thai Binh Province, Vietnam

Land ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 627
Author(s):  
Duong H. Nong ◽  
An T. Ngo ◽  
Hoa P. T. Nguyen ◽  
Thuy T. Nguyen ◽  
Lan T. Nguyen ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Agricultural Land ◽  
Land Use Changes ◽  
Management Strategies ◽  
Household Survey ◽  
Extreme Weather Events ◽  
Agricultural Land Use ◽  
Landsat 8 ◽  
Land Uses

We analyzed the agricultural land-use changes in the coastal areas of Tien Hai district, Thai Binh province, in 2005, 2010, 2015, and 2020, using Landsat 5 and Landsat 8 data. We used the object-oriented classification method with the maximum likelihood algorithm to classify six types of land uses. The series of land-use maps we produced had an overall accuracy of more than 80%. We then conducted a spatial analysis of the 5-year land-use change using ArcGIS software. In addition, we surveyed 150 farm households using a structured questionnaire regarding the impacts of climate change on agricultural productivity and land uses, as well as farmers’ adaptation and responses. The results showed that from 2005 to 2020, cropland decreased, while aquaculture land and forest land increased. We observed that the most remarkable decreases were in the area of rice (485.58 ha), the area of perennial crops (109.7 ha), and the area of non-agricultural land (747.35 ha). The area of land used for aquaculture and forest increased by 566.88 ha and 772.60 ha, respectively. We found that the manifestations of climate change, such as extreme weather events, saltwater intrusion, drought, and floods, have had a profound impact on agricultural production and land uses in the district, especially for annual crops and aquaculture. The results provide useful information for state authorities to design land-management strategies and solutions that are economic and effective in adapting to climate change.

scholarly journals Relative impacts of land use and climate change on summer precipitation in the Netherlands

2016 ◽  
Vol 20 (10) ◽  
pp. 4129-4142 ◽  
Author(s):  
Emma Daniels ◽  
Geert Lenderink ◽  
Ronald Hutjes ◽  
Albert Holtslag
Keyword(s):  
Climate Change ◽  
Land Use ◽  
The Netherlands ◽  
Land Use Changes ◽  
Wrf Model ◽  
Summer Precipitation ◽  
Circulation Type ◽  
Weather Research And Forecasting ◽  
Temperature Perturbation ◽  
Change Scenario

Abstract. The effects of historic and future land use on precipitation in the Netherlands are investigated on 18 summer days with similar meteorological conditions. The days are selected with a circulation type classification and a clustering procedure to obtain a homogenous set of days that is expected to favor land impacts. Changes in precipitation are investigated in relation to the present-day climate and land use, and from the perspective of future climate and land use. To that end, the weather research and forecasting (WRF) model is used with land use maps for 1900, 2000, and 2040. In addition, a temperature perturbation of +1 °C assuming constant relative humidity is imposed as a surrogate climate change scenario. Decreases in precipitation of, respectively, 3–5 and 2–5 % are simulated following conversion of historic to present, and present to future, land use. The temperature perturbation under present land use conditions increases precipitation amounts by on average 7–8 % and amplifies precipitation intensity. However, when also considering future land use, the increase is reduced to 2–6 % on average, and no intensification of extreme precipitation is simulated. In all, the simulated effects of land use changes on precipitation in summer are smaller than the effects of climate change, but are not negligible.

scholarly journals Can land use changes alter carbon, nitrogen and major ion transport in subtropical brazilian streams?

2007 ◽  
Vol 64 (4) ◽  
pp. 317-324 ◽  
Author(s):  
Daniela Mariano Lopes da Silva ◽  
Jean Pierre Henry Balbaud Ometto ◽  
Gré de Araújo Lobo ◽  
Walter de Paula Lima ◽  
Marcos Augusto Scaranello ◽  
...  
Keyword(s):  
Land Use ◽  
Sugar Cane ◽  
Dissolved Inorganic Carbon ◽  
Comprehensive Evaluation ◽  
Land Use Changes ◽  
Agricultural Practices ◽  
Major Ion ◽  
Se Brazil ◽  
Tropical Watersheds ◽  
The Impact

Several studies in tropical watersheds have evaluated the impact of urbanization and agricultural practices on water quality. In Brazil, savannas (known regionally as Cerrados) represent 23% of the country's surface, representing an important share to the national primary growth product, especially due to intense agriculture. The purpose of this study is to present a comprehensive evaluation, on a yearly basis, of carbon, nitrogen and major ion fluxes in streams crossing areas under different land use (natural vegetation, sugar cane and eucalyptus) in a savanna region of SE Brazil. Eucalyptus and sugar cane alter the transport of the investigated elements in small watersheds. The highest concentration of all parameters (abiotic parameters, ions, dissolved organic carbon DOC - and dissolved inorganic carbon - DIC) were found in Sugar Cane Watersheds (SCW). The observed concentrations of major cations in Eucalyptus Watersheds (EW) (Mg, Ca, K, Na), as well as DIN and DOC, were found frequently to be intermediate values between those of Savanna Watersheds (SW) and SCW, suggesting a moderate impact of eucalyptus plantations on the streamwater. Same trends were found in relation to ion and nutrient fluxes, where the higher values corresponded to SCW. It is suggested that sugar cane plantations might be playing an important role in altering the chemistry of water bodies.

scholarly journals Assessing the Opportunity Cost of Carbon Stock Caused by Land-Use Changes in Taiwan

Land ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1240
Author(s):  
Ming-Yun Chu ◽  
Wan-Yu Liu
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Carbon Storage ◽  
Carbon Emissions ◽  
Opportunity Cost ◽  
Carbon Stock ◽  
Agricultural Land ◽  
Land Use Changes ◽  
Market Price ◽  
The Government

As compared with conventional approaches for reducing carbon emissions, the strategies of reducing emissions from deforestations and forest degradation (REDD) can greatly reduce costs. Hence, the United Nations Framework Convention on Climate Change regards the REDD strategies as a crucial approach to mitigate climate change. To respond to climate change, Taiwan passed the Greenhouse Gas Reduction and Management Act to control the emissions of greenhouse gases. In 2021, the Taiwan government has announced that it will achieve the carbon neutrality target by 2050. Accordingly, starting with focusing on the carbon sink, the REDD strategies have been considered a recognized and feasible strategy in Taiwan. This study analyzed the net present value and carbon storage for various land-use types to estimate the carbon stock and opportunity cost of land-use changes. When the change of agricultural land to artificial forests generated carbon stock, the opportunity cost of carbon stock was negative. Contrarily, restoring artificial forests (which refer to a kind of forest that is formed through artificial planting, cultivation, and conservation) to agricultural land would generate carbon emissions, but create additional income. Since the opportunity cost of carbon storage needs to be lower than the carbon market price so that landlords have incentives to conduct REDD+, the outcomes of this study can provide a reference for the government to set an appropriate subsidy or price for carbon sinks. It is suggested that the government should offer sufficient incentives to reforest collapsed land, and implement interventions, promote carbon trading policies, or regulate the development of agricultural land so as to maintain artificial broadleaf forests for increased carbon storage.

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