Browsing by Subject "Land use change"

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Agrivoltaics: The environmental impacts of combining food crop cultivation and solar energy generation
(2023) Wagner, Moritz; Lask, Jan; Kiesel, Andreas; Lewandowski, Iris; Weselek, Axel; Högy, Petra; Trommsdorff, Max; Schnaiker, Marc-André; Bauerle, Andrea
The demand for food and renewable energy is increasing significantly, whereas the availability of land for agricultural use is declining. Agrivoltaic systems (AVS), which combine agricultural production with solar energy generation on the same area, are a promising opportunity with the potential to satisfy this demand while avoiding land-use conflicts. In the current study, a Consequential Life-Cycle Assessment (CLCA) was conducted to holistically assess the environmental consequences arising from a shift from single-use agriculture to AVS in Germany. The results of the study show that the environmental consequences of the installation of overhead AVS on agricultural land are positive and reduce the impacts in 15 of the 16 analysed impact categories especially for climate change, eutrophication and fossil resource use, as well as in the single score assessment, mainly due to the substitution of the marginal energy mix. It was demonstrated that, under certain conditions, AVS can contribute to the extension of renewable energy production resources without reducing food production resources. These include maintaining the agricultural yields underneath the photovoltaic (PV) modules, seeking synergies between solar energy generation and crop production and minimising the loss of good agricultural land.
Assessing alternative options to improve farming systems and to promote the adoption of low-carbon agriculture in Mato Grosso, Brazil
(2018) Carauta, Marcelo; Berger, Thomas
Currently, our society faces a significant challenge to eradicate hunger and poverty while preserving natural resources and reducing greenhouse gas (GHG) emissions. In this context, Brazil plays an important role since it is one of the most significant players in global food production and hosts a variety of ecosystems and a significant share of the Earths biodiversity. The federal state of Mato Grosso (MT) is located at the most dynamic agricultural frontier in the Cerrado-Amazon transition zone and leads the national production of grain, fiber, and meat. The need to balance agricultural production and environmental protection shifted the focus of Brazilian land-use policy toward sustainable agriculture. The federal government pledged to reduce its GHG emissions and implemented policies to enforce it. Brazils low-carbon agricultural plan offers credit with low-interest rate to farmers who want to implement sustainable agriculture practices. These include the restoration of degraded pasture, adoption of integrated systems, no-till agriculture, biological nitrogen fixation, commercial forests, treatment of animal wastes, and climate change adaptation. The present thesis contributed to the CARBIOCIAL project (“Carbon-optimized land management strategies for southern Amazonia”), a German-Brazilian cooperation to investigate viable carbon-optimized land management strategies maintaining ecosystem services under changing climate conditions in the Southern Amazon. In this context, this thesis examines options to improve farming systems in MT and evaluates policy measures that could promote the adoption of low-carbon agricultural systems. The work is divided into three parts: The first part is subdivided into three chapters (chapters 1, 2 and 3) and offers an overview on land use change in Brazil and explores land use decisions of farmers in MT, where highly dynamic double-crop systems currently prevail. The second part is subdivided into two chapters (chapters 4 and 5) and is dedicated to evaluating alternative options to improve farming systems in MT. The third part is subdivided into three chapters (chapters 6, 7 and 8) and investigates factors that may influence farmers to adopt IAPS, evaluates policy measures to promote the adoption of low-carbon agricultural systems, and provides a detailed quantification of individual GHG emissions of a large variety of agricultural practices and the aggregate emissions resulting from their current use in MT. To this end, this thesis develops an Integrated Assessment (IA) approach that simulates farm-level decision-making and agricultural land use change. It introduces a novel approach to evaluate the full distribution of GHG emissions related to the agricultural land-use change in MT. Our IA approach integrates three software packages: MPMAS (Mathematical Programming-based Multi-Agent Systems), MONICA (Model for Nitrogen and Carbon in Agro-ecosystems) and CANDY (Carbon and Nitrogen Dynamics). Data to parameterize the model was gathered from several sources, such as field experiments, statistical offices, farm level surveys from private consultancies, life-cycle inventory databases, extension services, expert interviews, and literature. This thesis presents the first extensive study on crop yield response in MT by simulating yields in response to different climatic conditions, soil types, sowing dates, crop rotation schemes, fertilization amounts, and macro-regions. The simulation results show that biophysical constraints still play a crucial role on yield gaps in MT whereas socio-economic constraints have a slight yield-increasing effect. This thesis further examines alternative ways to improve the farming systems in MT by investigating the role of sunflower adoption in increasing farm income. We have found a substantial potential for sunflower cultivation in MT with positive impacts on both farm and regional level. Additionally, we identified bottlenecks for sunflower diffusion such as the distance from farm gate to processing facility. Regarding Brazilian agricultural policy, we have found that the Brazilian low-carbon agricultural program contributed to the adoption of integrated systems. However, we observed different adoption rates through macro-regions and types of integrated systems. Furthermore, our simulations additionally show that the ABC program also contributed to the adoption of less GHG-emitting practices, but its performance is subjected to agent expectations on prices and yields
Developing a biodiversity evaluation tool and scenario design methods for the Greater Mekong Subregion
(2011) Cotter, Marc; Sauerborn, Joachim
The Xishuangbanna Prefecture in Yunnan Province (PR China) is facing increasing conflicts between rural development and nature conservation because of an ongoing expansion and commercialization of farming. The rapid development of large-scale farming and the improvement of infrastructure throughout the region are posing serious threats to the conservation of endemic species of flora and fauna, while also offering possibilities for enhancing the livelihood of rural populations to an extend never seen before. The expansion of rubber (Hevea brasiliensis Willd Ex A. Juss) has caused a reduction and fragmentation of natural and secondary forest cover, thereby decreasing structural and species diversity as well as the loss of valuable ecosystem services. The establishment of intensified agriculture, especially plantations on sloping terrain, often leads to an increased erosion risk, nutrient run-off and sedimentation in water courses. Thus, large scale deforestation is not just a problem for nature conservation but also one for the rural economies. Rural development and simultaneous environment conservation often face trade-offs, especially in regions that host an exceptionally high biodiversity, such as many tropical areas. In order to adequately consider and evaluate these interactions, tools and methods have to be developed that allow decision makers to assess the impacts of different management and infrastructure options on the environment. The aim of the work presented in this thesis was to analyze and evaluate the effect of large-scale rubber cultivation on local and regional biodiversity by developing methods to integrate field studies from various disciplines into a comprehensive assessment model. This model was then used to highlight key aspects of anthropogenic influence on the plant species composition within the research area and to identify possible impacts of alternative land use decisions. Furthermore, the development of an interdisciplinary approach to scientific scenario design methods has been supplemented with a study on the acceptance of 3D-visualization as communication tool for land use planning in the background of nature conservation sciences. In order to achieve this, an overview of the agronomical and ecological aspects of rubber cultivation was provided. Literature sources referring to the impact of different cultivation systems on natural biodiversity were discussed and an introduction to the effect of rubber cultivation on Ecosystem Services was given. A method for projection of regionally adapted carbon capture properties of rubber cultivation under suboptimal growth conditions was presented and a comparative assessment of greenhouse gas emissions during the establishment of rubber plantations in regard to the preexisting vegetation was made. A biodiversity evaluation tool based on the combination of approaches from landscape ecology and empirical data within a Geographic Information System was developed. Detailed data on plant species diversity and distribution were combined with quality criteria like endemism or invasiveness to form spatially explicit biodiversity indices for different land use types in various elevation classes. Up-scaling in accordance to the land use distribution observed allowed the estimation of overall plant diversity and the evaluation of the effect of possible future land use scenarios. Habitat characteristics and spatial distribution were included into the analysis of the land use map derived from remote sensing information to allow for the assessment of fragmentation and landscape matrix structure. The methodology was tested with an array of possible present and future land use maps. It was possible not only to evaluate the different land use classes within and their distribution throughout the research area, but we were also able to compare distinct sub-regions based on topography or administrative status. The challenges stakeholders and nature conservation face in the different elevation zones of Nabanhe were highlighted and related to the findings of our partner workgroups from economy and social sciences. The feasibility of this approach to administration staff with limited experience in ecological modeling was one of the main goals in designing the methods. Given a reasonable data set on species diversity and distribution within any given tropical research area, this approach will enable planners and nature park administration to quickly project possible consequences on species diversity indices deriving from land use change within their respective research area. Using this approach, the importance of natural tropical forests for the maintenance of species diversity in tropical cultivated landscapes was highlighted. With the information gained from constructing this evaluation tool, the design and development process for a land use scenario based on the integration of multidisciplinary assessments and iterative scenario refinement with repeated stakeholder inclusion was promoted. By combining stricter conservation rules with alternative sources of income for the rural population in order to offer an alternative to monoculture rubber farming, the economic models and the land use allocation model predicted a stop in rubber and agriculture related deforestation, and the establishment of a considerable amount of reforested area. This was achieved by introducing an innovative land use type that is closely related to traditional local home garden agroforestry systems. By coupling reforestation efforts with the economic gain derived from intercropping Traditional Chinese Medicinal plants into degraded secondary forests, this scenario was, at least theoretically, able to remove deforestation pressure from the natural forest types and to offer an economic alternative to rubber cultivation. The methods used for this assignment can serve as guideline for future projects that want to implement scenario design procedures based on the combination of social sciences, economics, ecology and landscape planning. The acceptance and comprehensibility of computer based 3D visualization models for the communication of possible future land use scenarios was also tested. Two alternative scenarios were visualized and compared to the status quo, with questionnaires and guided interviews covering the acceptability and adaptability of such techniques for professionals from various fields of nature conservation. This thesis presents an overview over agronomic, economic and ecological aspects of rubber cultivation and highlights its implications on biodiversity and nature conservation. The methods discussed here can serve as a guideline for the integration of ecological indicators in land use planning and decision making processes. Although the concepts and topics introduced herein are closely interlinked within the framework of the Living Landscapes China (LILAC) research project, the methods and approaches can easily be applied to other areas in the Greater Mekong Subregion and beyond, be it the expansion of oil palm plantations in the Malayan Archipelago or the fragmentation of forests due to increased population pressure in Central Africa. Nature conservation is facing similar problems all over the developing world, and adaptable approaches such as the ones presented here are needed to support decision making processes in order to secure the preservation and long-term survival of the worlds? diversity in species and natural habitats.
Land use change, agricultural intensification and low-carbon agricultural practices in Mato Grosso, Brazil
(2016) Dias Bernardes Gil, Juliana; Berger, Thomas
The process of land use change in Brazil has implications for food security, climate change and socioeconomic development at the local, regional and global levels. Largely driven by agricultural expansion over the past decades, such processes are likely to become even more pronounced in the coming years as Brazil is expected to satisfy a significant share of the global demand for food and energy. In an effort to prevent further forest clearance and associated greenhouse gases (GHG) emissions, the Brazilian Federal Government has been promoting agricultural intensification through farming practices able to increase crop and livestock productivity while restoring degraded lands. Particular attention has been dedicated to the beef cattle sector in Mato Grosso state, a globally important center of agricultural production in Southern Amazonia, where some of the highest crop productivity levels contrast with pastures of low average stocking rates. Two agricultural intensification strategies of growing importance in Mato Grosso are pasture to crop conversion (P2C) and integrated crop-livestock-forest systems (IS). While the first is a consequence of cropland expansion on pastures and might continue to happen through expected shifts in the relative profitability of certain commodities, the second entails the adoption of complex management practices and may be conditional on incentives and the existence of a favorable institutional context. Even though the Federal Government has already established policies and programs to promote P2C and IS and relies on both to reduce its total GHG emissions, the level of IS adoption remains low and many aspects of P2C and IS –including the drivers, barriers and impacts associated to their adoption –are poorly understood. This thesis sheds light on some of these uncertainties, elucidating where, how and why P2C and IS happen. Using a combination of qualitative and quantitative research methods such as surveys, focus groups, remote sensing, spatial econometrics and agent-based modeling, it seeks a better understanding of the interplay between farmers’ characteristics and preferences, supply chain infrastructure, market conditions and institutional factors, as well as how these may constrain or catalyze specific LUC pathways. Based on these findings, it ultimately compares the impacts of P2C and IS and concludes that the latter may offer greater benefits. The Introduction contextualizes the research questions explored in the subsequent chapters by offering an overview of land use change in Brazil and briefly reviewing the literature on agricultural intensification. The following chapters (2, 3, 4 and 5) form the core of the thesis and correspond to scientific publications developed during the Ph.D. program, all focused on Mato Grosso. Results are analyzed in an integrated manner under Discussion & Conclusion in light of the broader implications of agricultural intensification through P2C and IS, finally leading to policy recommendations. Chapter 2 quantifies P2C and investigates its drivers, revealing that: i) cattle vs. soy profitability and land prices do not fully explain P2C location; ii) land attributes on which classical agricultural development theories are based, may favour P2C but do not fully explain it; and iii) socioeconomic and institutional constraints are important in controlling pasture conversion, including non-productive sources of utility, producers’ perception of contract enforcement, land markets and P2C-related transaction costs. Chapters 3, 4 and 5 are dedicated to IS. Chapter 3 reveals the state-of-the-art of IS and how farmers perceive it, showing that: i) IS were concentrated in less than a third of the counties of Mato Grosso state –most of which were crop-livestock systems (iCL); ii) producers usually adopted one of three iCL strategies; and iii) the strategy choice was correlated with the land use transition undergone by each producer. Building on these findings, chapter 4 examines the determinants of wide-scale IS adoption and assesses the importance of household- and county-level variables, revealing that: i) adopters of iCL systems are better educated and have more access to technical assistance than specialized producers; ii) greater similarity exists between counties with iCL systems and soy-dominant vs. pasture-dominant counties; and iii) the presence of soy and pasture in a county is not a predictor of the occurrence of iCL systems. Finally, chapter 5 employs a bio-economic model that assesses how effective credit provision is in supporting the adoption of low-carbon systems –specifically IS and planted forests. The model simulates future land use changes in Mato Grosso under different credit scenarios and suggests that: i) credit has the potential to prompt greater adoption of IS; and ii) changes in the credit conditions (e.g. interest rates, down payment share and capital requirements) influence rates of IS adoption differently. Most existing studies on land use change in Brazil are limited to the debate between intensification vs. extensification and tend to project the effects of intensification at an aggregate level, overlooking the different drivers and impacts of specific intensification pathways. By exploring the particularities of IS and P2C, this work offers evidence that these are two distinct intensification strategies with widely different impacts – and, thus, should not be treated indistinguishably by policy makers. The merit of this thesis relies not only on its innovative theoretical approach, but also on its multidisciplinary and multi-scale nature. Through the mapping, measurement, description and interpretation of IS and P2C, it provides results able to inform policy making, facilitate the monitoring of existing policies and set the ground for subsequent research.
Rainforestation farming on Leyte island, Philippines - aspects of soil fertility and carbon sequestration potential
(2007) Marohn, Carsten; Sauerborn, Joachim
This study aimed at investigating rainforestation systems in Leyte, Philippines, under different aspects: Characterisation of typical soils in Leyte with respect to physical, chemical and biological parameters relevant for tree growth, possible contributions of rainforestation to restoring soil fertility, performance of a recently planted rainforestation system under different microclimatic and soil conditions, potential of the rainforestation approach for projects under the umbrella of the Clean Development Mechanism (CDM). Soils in Leyte can be grouped into a volcanic and a calcareous category. The latter were formed on coralline limestone and are high in pH and Ca2+ and Mg2+. Contents of organic matter are high while concentrations of plant available PBray are low. Volcanic soils are characterised by low pH and CEC as well as extremely low PBray contents. Organic matter levels are below those of the calcareous soils but still moderate. In any analysed soil, N would not limit tree growth. Pore volume and water infiltration were propitious for all sites, which is relevant in the context of erosion. For calcareous soils, drought and reduced rootability due to clayey subsoil posed the most relevant constraints. The frequently claimed role of rainforestation in the rehabilitation of degraded soils was assessed in a paired plot approach. Chemical and biological soil parameters under 10 year old rainforestation were contrasted with adjacent fallow or Gmelina sp. Clear tendencies across all seven sampled sites were lower available Mg2+ and pH under rainforestation. Other differences were less distinct. Generally, a depletion of soil reserves e.g. in basic cations can be explained by uptake into the plants. A feed-back of these elements to the topsoil via leaf litter, however, could be observed only for available P. In conclusion, plant uptake of single elements can reach orders of magnitudethat reduce soil stocks. At the same time, generally lower pH under rainforestation may have contributed to elevated losses, especially of basic cations. A general improvement of the sampled soils in terms of chemical or biological characteristics through rainforestation could not be observed. To evaluate plant performance six timber and four fruit species, most native, were interplanted on a 1ha plot. Rainforestation, commonly understood as high-density closed canopy system was modified to a less dense 5x5m grid, interplanted with Musa textilis. The plot varied strongly on a small scale due to heterogeneous canopy closure and relief. Methodologically, the entire area was divided into 10 subplots in representative positions to be sampled. Soil physical and chemical properties, microbial activity, PAR and root length density were determined and correlated to plant survival and growth at consecutive inventories. For Musa textilis, the most sensitive species, which was used as an indicator, logistic regressions were calculated to determine the influence of all relevant parameters on survival rates. The most important predictors for survival were organic matter contents, parameters related to biological activity and leaf litter production, which resembled canopy closure and thus indirectly light intensity and soil moisture. To assess growth, multiple regressions were formulated for biomass at five inventories. Corg and NLOM were the most relevant variables determining the regressions used for biomass and growth of abaca. Assessing the potential of rainforestation for Clean Development Mechanism (CDM) measures, amounts of sequestered CO2 during 10 and 20 years, respectively, were estimated under different management options using the WaNuLCAS model. Despite all given uncertainty associated with modelling, one very obvious finding was the dominant role of soil carbon for the plot balance: Appropriate soil management, especially during land preparation (e.g. clearing vs. enrichment planting) is of paramount importance. Looking at the modelled contribution of various tree species to the carbon balance, Musa textilis had a significant influence only during the very first years; later on, the principal share of carbon was bound in the tree component. Here, exotic Gmelina arborea built up biomass more quickly than a rainforestation plot composed of native Shorea contorta and Durio zibethinus, but was then overtaken. In absolute quantities of CO2 sequestration, magnitudes matched inventory and modelled data given in various literature sources for Leyte and the Philippines. Relative to earlier inventory data from two rainforestation sites, modelled values overestimated growth.
Simulating the impact of land use change on ecosystem functions in data-limited watersheds of Mountainous Mainland Southeast Asia
(2015) Lippe, Melvin; Cadisch, Georg
The presented PhD thesis deals with the development of new modelling approaches and application procedures to simulate the impact of land use change (LUC) on soil fertility, carbon sequestration and mitigation of soil erosion and sediment deposition under data-limited conditions, using three mountainous watersheds in Northern Thailand, Northern and North-western Vietnam as case study areas. The first study investigated if qualitative datasets derived during participatory processes can be used to parameterize the spatially-explicit, soil fertility-driven FALLOW (Forest, Agroforest, Low-value Landscape Or Wasteland?) model. Participatory evaluations with different stakeholder groups were conducted in a case study village of Northwest Vietnam to generate model input datasets. A local colour-based soil quality classification system was successfully integrated into the FALLOW soil module to test scenarios how current or improved crop management would impact the evolution of upland soil fertility levels. The scenario analysis suggested a masking effect of ongoing soil fertility decline by using fertilizers and hybrid crop varieties, indicating a resource overuse that becomes increasingly irreversible without external interventions. Simulations further suggested that the success rate of improved cropping management methods becomes less effective with increasing soil degradation levels and cannot fully restore initial soil fertility. The second case study examined the effects of LUC on the provisioning of long-term carbon sinks illustrated for a case study watershed in Northern Thailand. Based on land use history data, participatory appraisals and expert interviews, a scenario analysis was conducted with the Dyna-CLUE (Dynamic and Conversion of Land use Effects) model to simulate different LUC trajectories in 2009 to 2029. The scenario analysis demonstrated a strong influence of external factors such as cash crop demands and nature conservation strategies on the spatial evolution of land use patterns at watershed-scale. Coupling scenario-specific LUC maps with a carbon accounting procedure further revealed that depending on employed time-averaged input datasets, up to 1.7 Gg above-ground carbon (AGC) could be built-up by increasing reforestation or orchard areas until 2029. In contrast, a loss of 0.4 Gg in AGC stocks would occur, if current LUC trends would be continued until 2029. Coupled model computations further revealed that the uncertainty of estimated AGC stocks is larger than the expected LUC scenario effects as a function of employed AGC input dataset. The third case study examined the impact of land use change on soil erosion and sediment deposition patterns in a small watershed of mountainous Northern Vietnam using a newly developed dynamic and spatially-explicit erosion and sediment deposition model (ERODEP), which was further coupled with the LUCIA (Land Use Change Impact Assessment) model building on its hydrological and vegetation growth routines. Employing available field datasets for a period of four years, ERODEP-LUCIA simulated reasonably well soil erosion and sediment deposition patterns following the annual variations in land use and rainfall regimes. Output validation (i.e. Modelling Efficiency=EF) revealed satisfying to good simulation results, i.e. plot-scale soil loss under upland swiddening (EF: 0.60-0.86) and sediment delivery rates in monitored streamflow (EF: 0.44-0.93). Cumulative sediment deposition patterns in lowland paddy fields were simulated fairly well (EF: 0.66), but showed limitations in adequately predicting silt fractions along a spatial gradient in a lowland monitoring site. In conclusion, data-limited conditions are a common feature of many tropical environments such as Northern Thailand and Northern/North-western Vietnam. Environmental modellers, decision makers and stakeholders have to be aware of the trade-offs between model complexity, input demands, and output reliability. It is not necessarily the challenge of data-limitations, but rather the decision from the very beginning if the aim is to develop a new model tool or to use existing model structures to support environmental decision making. Future modelling-based investigations in data-limited areas should combine scientifically-based approaches with participatory procedures, because scientific assessment can support environmental policy making, but stakeholders’ decision will finally determine the provisioning of ecosystem functions in the long run. A generic assessment framework is proposed as synthesis of this study to employ dynamic and spatially-explicit models to examine the impact of LUC on ecosystem functions. The application of such a generic framework is especially useful in data-limited environments such as Mountainous Mainland Southeast Asia, as it not only provides guidance during the modelling process, but also supports the prioritisation of input data demands and reduces fieldwork needs to a minimum.