Das Projekt "B 2.3: Transport of agrochemicals in a watershed in Northern Thailand - Phase 3" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Bodenkunde und Standortslehre, Fachgebiet Biogeophysik durchgeführt. Land use changes of the last decades in the mountainous regions of Northern Thailand have been accompanied by an increased input of agrochemicals, which might be transferred to rivers by surface and/or subsurface flow. Where the river water is used for household consumption, irrigation and other purposes, agrochemical losses pose a serious risk to the environment and food safety. In the first and the second phase, subproject B2 collected data on and gained knowledge of the vertical and lateral transport processes that govern the environmental fate of selected agrochemicals at the plot and the hillslope scale (Ciglasch et al., 2005; Kahl et al., 2006). In the third phase, B2.3 will turn from the hillslope to the watershed scale. For simulation of water flow and pesticide transport the SWAT model (Neitsch et al., 2002b) will be adapted and used. The study area will be the Mae Sa watershed (138 km2), which includes the Mae Sa Noi subcatchment where B2 carried out detailed investigations during the last two phases. The specific focus of the subproject will be the parameterization and calibration of the SWAT model and its integration into the model network of the SFB. The SFB database has been established and can be used for model parameterization. In addition, high-quality geo-data are available from the Geoinformatic and Space Technology Development Agency (GISTDA) in Chiang Mai. For model calibration, discharge measurements are available for the Mae Sa Noi subcatchment (12 km2) and for the neighboring Mae Nai subcatchment (18 km2). To collect data on the Mae Sa watershed discharge, at the very beginning of the third phase gauging stations will be established in a midstream position and at the outlet of the watershed. Pesticide fluxes will be measured at each gauging station as well as in the Mae Sa Noi subcatchment, where B2.2 has operated two flumes equipped with automatic discharge-proportional water samplers since 2004. Rainfall distribution and intensity will be monitored with a net of automatic rain gauges. Hydrograph separation will be performed using soil and river temperatures (Kobayashi et al., 1999). Within the watershed temperature loggers will be installed at different soil depths to measure the temperature of the different discharge components. Already at the beginning of the second year of the third phase we will start to couple the SWAT model with land use and farm household models of the SFB and to use the model to assess the effect of land use and land management changes on the loss of pesticides to surface waters.
Das Projekt "D 6.1: Improving fruit set and quality standards of mango in the mountainous area of Vietnam" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Kulturpflanzenwissenschaften, Fachgebiet Ertragsphysiologie der Sonderkulturen (340f) durchgeführt. A major problem in mango production in Northern Vietnam is a premature fruit drop. However, the underlying plant processes in response to environmental and/or crop management factors are not understood. There is a general belief that this phenomenon is caused by different combinations of stressing factors which may vary between different regions and sites. In the mountainous area of northern Vietnam (Son La Province), fruit drop in mango may be caused by relatively hot, dry prevailing winds which typically occur in February/March. Consequently, it has to be determined which plant process responds sensitively to specific environmental conditions and subsequently causes, through its alteration, premature fruit drop. The identification of the physiological basis of premature fruit drop not only is of scientific interest but also of commercial significance, allowing the development of effective, fruit drop reducing crop management strategies and thus ensuring a economically sustainable cultivation of mango in this region. The research project has two main parts; environmental crop physiology and fruit quality. The environmental crop physiology part investigates whether premature fruit drop is caused by high temperature/vapour pressure deficit (VPD) conditions and related to: 1. temperature dependence of pollen tube growth and flower quality; 2. altered carbon fixation and carbon partitioning between sources (leaves) and sinks (fruit), thus possible limitations of carbon supply to developing mango fruit; 3. altered basipetal auxin export from fruit and fruit ethylene concentration. The fruit quality part will primarily carry out sensory fruit analyses and establish harvest quality criteria with the aim to improve the economic returns and thereby the economic situation of the fruit growers in the long-term.
Das Projekt "Element cycles in mountain regions under various land use" wird vom Umweltbundesamt gefördert und von Universität Bayreuth, Fachgruppe Geowissenschaften, Bayreuther Zentrum für Ökologie und Umweltforschung (BayCEER), Lehrstuhl für Agrarökosystemforschung durchgeführt. Research question: What is the role of agricultural land use in changes of nutrient cycles and losses dependingon surface slope and climate? Approach: Annual balance of main nutrients for 3-4 main agricultural farms based on fertilizer input, partitioning of nutrients in above and below ground plant parts, output with harvest, losses with DOM and erosion (in collaboration with other TP). The balances will be done depending on agricultural practices in Eger and Haean Catchment and will be compared with adjacent grassland and forest. Obtained element cycles will be upscaled from farm area to the level of both catchments basins depending on specific land use, surface slope and climate. Research question: Can we reconstruct previous erosion and nutrient losses and separate them under forest and under agricultural use? Approach: Undisturbed sediment cores (7 for Eger and 7 for Haean) will be taken from the lakes and soils of landscapes subordinated to agricultural fields. Three radiocarbon data of wood particles at increasing depth for each sediment core will be used as references. The age of the bottom sediment layer should be less than 1000 years. The total content of C, N, P, K, Mg, Ca, Si will be analyzed in individual laminae or sediment layers. Conclusions will be drawn based on the thickness of the laminae, their elements content and the ratio between nutrients and Si. The conclusions will be proven by 13C (vegetation change) and 15N (N input by fertilizers) of individual laminae. Research question: What are the best management practices for sloping uplands? Approach: Measured element cycles and losses under various agriculture practice will be analysed and practices with the least nutrient losses and erosion will be selected. The best management practices for landscapes with different slopes will be elaborated.
Das Projekt "B 2: Lateral water flow and transport of agrochemicals - Phase 1" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Bodenkunde und Standortslehre durchgeführt. The project aims at developing a model of the dynamics of agrochemicals (fertilisers, pesticides) and selected heavy metals on a regional scale as a function of cropping intensity in the highland areas of Northern Thailand. The model shall predict the effects of cropping intensity on mobility and leaching of agrochemicals in the agriculturally used system itself but also on the chemical status of neighbouring ecosystems including downstream areas. The methods for measuring and estimating the fluxes of agrochemicals in soils will be adapted to the conditions of the soils and sites in Northern Thailand. Fluxes of agrochemicals will be measured in fruit tree orchards on the experimental sites established together with projects B1, C1 and D1. Also, processes governing the dynamics of agrochemicals will be studied. The objectives for the first phase are as follows: - To identify suitable study sites - To establish the methods for measuring the fluxes of agrochemicals in the study sites - To adopt the analytical procedures for pesticides - To identify and parametrise the processes governing the mobility of agrochemicals - To identify the major chemical transformation processes for agrochemicals in the soils of the project area - To establish models of the fate of agrochemicals an the plot scale. Dynamics of agrochemicals include processes of mobilisation/immobilisation, degradation and transport. Both, experiments and field inventories are needed to elucidate the complex interaction of the various processes. Field measurements of the fluxes of nutrient elements (N, P, K, Ca, Mg, Mn, Zn, Cu), pesticides and some heavy metals will be conducted at different regional scales (plot, agricultural system, small catchment, region). Laboratory and field experiments consider chemical, physicochemical and biological processes. Biological processes and degradation of pesticides will not be considered in the first phase of the project, however, they should be included later on. The project as a whole is broken down into three essential parts, which consecutively follow each other. The subproject is methods- and processes-orientated. Methods, which were developed in Hohenheim to quantify the fluxes of chemicals in soils have to be adapted to meet the requirements of the specific conditions in the study area. Recently, these methods are already under development in tropical environments (Vietnam, Costa Rica). After adaptation the methods will be used to yield flux data on the plot scale. These data are needed to help deciding which of the hypothesised processes are of major importance for modelling the dynamics of agrochemicals. The final outcome of this project phase are models of the fate of agrochemicals as a function of management intensity on the plot scale.
Das Projekt "Plant-soil interactions in changing rice cropping systems and their influence on C and N dynamics" wird vom Umweltbundesamt gefördert und von Universität Bonn, Institut für Nutzpflanzenwissenschaften und Ressourcenschutz - Pflanzenernährung (Prof. Werner) durchgeführt. Plant-soil interactions drive the input, cycling and losses of C and N in soil. This subproject aims at elucidating the input and fate of C in the soil-plant systems and its effect of N retention in soil under different paddy management (continuous vs. alternating with maize cropping). In particular we will investigate (i) how much of the assimilate C is released by the plants into the rhizosphere soil, and how this rhizodeposition is affected by N supply, soil density and crop variety during plant development, (ii) how the exudation of C and N responds to land use change, (iii) how C released into the rhizosphere affects the turnover of soil C and utilization of fertilizer N, and (iv) to what degree leaching contributes to the loss of C and N from the rooted surface soil. To answer these questions, we will combine the use of isotopic 13C and 15N labeling in laboratory and field experiments with a sophisticated characterization of root exudates, root border cells, and compound-specific isotope tracing in the residues of bacteria and fungi in rhizosphere, bulk soil as well as within different dissolved organic and inorganic carbon species in soil leachates. In this way and in collaboration with SP 2, 5, 6, and 7 of this research unit, our project links the cycling of C and N in paddy soils to one of its most prominent drivers, the release of organic compounds by roots.
Das Projekt "Soil N dynamics as affected by different land use in Western and Southern China" wird vom Umweltbundesamt gefördert und von Technische Universität Dresden, Institut für Bodenkunde und Standortslehre durchgeführt. The aim of the research project is to quantify the stocks and turnover of soil nitrogen in Western and Southern China as dependent from soil structure and land use. Key soil characteristics are determined at representative sites with regional specific land use and degradation status. The investigations will follow a land use gradient of natural forests, arable and pasture soils, the latter ones considering different degradation and rehabilitation status. The actual and potential soil nitrogen turnover will be horizon-wise quantified and related to soil structure and land use impacts. Beside mineral nitrogen, also preliminary organic N compounds using physical and chemical extraction will be detected. Parameters for the investigations are, beside total C and N stocks and distribution, gross and net N mineralization, nitrification, microbial biomass C and N and microbial respiration and indicators for soil N turnover like active N pools and light fraction of organic matter. In the last phase the structure of the soil microbial microbial community will be determined and related to indicators of nitrogen status and efficiency. The research activities will be carried out in close co-operation with the Institute for Soil and Water Conservation/ Yangling University at loess soils and the Nanjing Institute for Soil Science/ Chinese Academy for Science in Nanjing at red soil sites.
Das Projekt "Teilprojekt A" wird vom Umweltbundesamt gefördert und von Universität Gießen, Institut für Angewandte Mikrobiologie, Professur für Allgemeine und Bodenmikrobiologie durchgeführt. Wheat and barley production will be optimized under low energy input in organic farming at two experimental field stations of University Giessen and University Hohenheim. Effects of root densities (row distance), two nutrients fertilization regimes and seed inoculation of the plant growth promoting bacterium Hartmannibacter diazotrophicus will be analyzed in wheat as an important winter crop and in the summer crop barley. Quality parameters of produced grains differ for the two crops. For baking wheat protein quality and quantity is important while for malting barley high starch content is required. These parameter of the grains will be related to their root system and rhizosphere microbiome under the different treatments. The seed, root and rhizosphere bacterial and fungal microbiome will be analysed and it is expected to be specific for the two crop plants and less affected by the two soil types and locations. We aim to analyze the implication of root competition, nutrient limitation and seed inoculation on the microbiome under field conditions. Root competition will be analyzed using two different row distances under a low and optimal nitrogen fertilization regime. The plant root system might further profit from the inoculum and benefits would be derived from a more efficient root system that could capture N from fertiliser-soil sources more effectively, as well as more efficient N cycling might occur. Root architecture and biomass will be linked to microbiome analysis and grain quality and quantity. Before seeding and after harvest soil samples are analyzed for parameter estimating the sustainability of crop production. Such parameter include bacterial and fungal diversity, microbial respiration rate, soil N concentrations, protease and nitrification activity, phosphate concentration and phosphatase activity. Our results will be used for identification of optimal parameter for sustainable wheat and barley production and will lead to a bioeconomic evaluation.
Das Projekt "D 1.2: Reducing alternation and production of off-season fruits in Lychee, Longan and Mango" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Kulturpflanzenwissenschaften (340), Fachgebiet Düngung und Bodenstoffhaushalt (340i) durchgeführt. The aim and vision of sub-project D1.2 was and is to encourage hillside farmers to plant erosion resistant fruit trees instead of erosion susceptible annual plants. For that reason, experiments to overcome the irregular bearing behaviour of the three most common fruit tree species in Northern Thailand (Litchi, Longan and Mango) from the first SFB period will be continued in order to make their planting more attractive to the farmers. Considerable progress has been made in D1 during the past 3 years to induce flowers and fruit in Longan trees by the application of KClO3 . With this technique, it was not only possible to induce year around flowers and fruit (off season fruit) but also to overcome the generally rather irregular fruiting behaviour of these trees. A similar technique is now being developed for Mango by using an inhibitor of the bio-synthesis of the plant hormone gibberellin. Only Litchi still resist this kind of manipulation by an 'off season technique' (OST). Great effort will therefore be devoted establishing a similar system for this species as well. Reliably, this can only be done by gaining a much better knowledge of the - most certainly hormonal - regulatory system that governs flower induction in trees. Investigations into the hormonal changes taking place during natural and induced flower induction is, therefore, one of the central objectives in this sub-project, with the goal to better understand the process of flower induction. Until now most of the progress in this area is entirely empirical in nature and a more specific manipulation therefore difficult. While the ability to produce off season fruit all year around and under various weather conditions has brought about a great number of new possibilities, new challenges will still be faced with regard to these methods. These circumstances will affect the whole production chain from the orchard to the market and consumer. In order to better investigate and understand these new situations, a large model experiment with Mango will be set up and problems like tree pruning, water and nutrient demand, phytopathological problems, demand on work force, fruit processing and drying etc. will be investigated by the interdisciplinary co-operation of 8 sub-projects within the SFB. The results obtained during these investigations will be shared with hillside farmers enabling them to take advantage of these new possibilities, which will provide for more reliable yields and allow them to market fruit year around. In general, these new opportunities should encourage farmers to plant more trees and thus reduce erosion. However, to make this system not only reliable and economic but also ecologically and socially beneficial to the society all potential benefits as well as risks have to be evaluated carefully from all different aspects.
Das Projekt "Teilprojekt B" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Kulturpflanzenwissenschaften (340), Fachgebiet Qualität pflanzlicher Erzeugnisse (340e) durchgeführt. Wheat and barley production will be optimized under low energy input in organic farming at two experimental field stations of University Giessen and University Hohenheim. Effects of root densities (row distance), two nutrients fertilization regimes and seed inoculation of the plant growth promoting bacterium Hartmannibacter diazotrophicus will be analyzed in wheat as an important winter crop and in the summer crop barley. Quality parameters of produced grains differ for the two crops. For baking wheat protein quality and quantity is important while for malting barley high starch content is required. These parameter of the grains will be related to their root system and rhizosphere microbiome under the different treatments. The seed, root and rhizosphere bacterial and fungal microbiome will be analysed and it is expected to be specific for the two crop plants and less affected by the two soil types and locations. We aim to analyze the implication of root competition, nutrient limitation and seed inoculation on the microbiome under field conditions. Root competition will be analyzed using two different row distances under a low and optimal nitrogen fertilization regime. The plant root system might further profit from the inoculum and benefits would be derived from a more efficient root system that could capture N from fertiliser-soil sources more effectively, as well as more efficient N cycling might occur. Root architecture and biomass will be linked to microbiome analysis and grain quality and quantity. Before seeding and after harvest soil samples are analyzed for parameter estimating the sustainability of crop production. Such parameter include bacterial and fungal diversity, microbial respiration rate, soil N concentrations, protease and nitrification activity, phosphate concentration and phosphatase activity. Our results will be used for identification of optimal parameter for sustainable wheat and barley production and will lead to a bioeconomic evaluation.
Das Projekt "SP 2.3 Decision support systems for weed management in North China Plain production systems" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Tropische Agrarwissenschaften (Hans-Ruthenberg-Institut) (490), Fachgebiet Agrarökologie der Tropen und Substropen (490f) durchgeführt. Wide applications in Europe show that weed management strategies can be considerably improved when computerized expert systems, decision models and population-dynamic models are applied. If these management systems are transferred and adapted to the specific production systems of the North China Plain, herbicide use can be significantly reduced and the evolution of persistent weed populations in the major arable crops can be avoided. The main objective of this subproject will be to create efficacy-based models analyzing herbicide performance in major crops and to create population-based models for herbicide use analyzing the yield losses caused by weed competition. For these models it is necessary to determine the sensitivity of major weed species to herbicides and to explore the potential of reduced dose rates for herbicide use. Furthermore it is necessary to investigate weed management practices combining preventive (timing of seeding, crop rotation and tillage) and direct methods (chemical and physical methods) of weed control. For population dynamic models it is necessary to determine long-term economic weed threshold estimating the changes in the soil seed bank. Finally both models will be combined in a decision support system for weed control in North China Plain Production Systems. The applicability of this decision support system will be tested in field experiments.
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