Browsing by Subject "Umwelt"

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Economic analysis on the agro-environmental impacts of management and policy measures in the North China Plain
(2011) Kühl, Yannick; Zeddies, Jürgen
The increased use of agricultural inputs like fertilizers and pesticides led to wide-spread negative environmental impacts of agriculture in the North China Plain (NCP). The context of this research is that, due to continued growth of the population and the economy, the demand for agricultural products in China is gradually rising. However resources like land and water are scarce in China. Therefore new strategies need to be developed which do not put additional strains on the environment but meet the expected demand. The NCP is regarded as China?s most important agricultural region. This work aims at describing and discussing the environmental effects of agriculture in the NCP. The extent of these environmental impacts is presented. An essential part of this work is the in-depth description and analysis of the current cropping systems and farming practices, which is based on the findings a household survey. The central hypothesis of this work is that a change of the management systems is able to meet the production goals, to achieve a higher input-output efficiency and to reduce negative environmental impacts. Embedded in the objectives of this work, the main goals are the description of current agricultural practices and related negative environmental impacts, the definition of agro-environmental management and policy measures, impact analysis of management and policy measures and the development of suggestions for further research. The second chapter aims at introducing the background of this research, i.e. the environmental impacts of agriculture. Hereby the focus lies on the introduction of relevant and characteristic farming practices and on the related institutional setting. Then the processes of data acquisition and data handling for this work are described. The descriptive analysis presents the findings from a survey in July 2008; it aims at describing the characteristics of the surveyed farm households. Chapter 5 describes the methodologies which are applied for the analysis in this work. The first part describes the methodology of Linear Programming and its selection process. The second part explains the selection process for the integrated households. The last part describes the processes of environmental assessment by means of selected indicators. In chapter 6 the model is applied to simulate and analyze the selected households in changing scenarios. Each Scenario is described individually. Then the simulation results are presented and discussed. In chapter 7 possible strategies to reduce environmental impacts of farming in the NCP ? considering the objectives of this work: sustainability and food security ? are discussed. The discussion focuses on the two main problems in the research area: fertilization and water. The analysis showed that current farming practices in the research area are not sustainable and can, thus, threaten future food security in China. The dilemma of the research area is that intensive agricultural production cannot be reduced because high yields are needed to feed the growing demand from a (economically) growing population. Simultaneously high resource consumption and pollution from farming cannot continue as that could eventually result in irreversible damage to agriculture in the NCP and also threatens livelihoods. Finally strategic policy recommendations, characteristics of improved management practices and recommendations for further research are presented. These recommendations can play an important role in decision guiding for policy makers. After reviewing other studies in the NCP, it has to be concluded that this work represents one of the most comprehensive analysis of the agricultural practices in the Hebei province. It was demonstrated that management practices for maize and wheat exist which can result in higher input-output efficiency and which are economically more profitable ? especially production options which include intercropping of other crops or demand-driven fertilization and irrigation. The hypothesis was tested to be valid. The simulation of optimization options showed that economically more profitable production options exist. These optimized production options are characterized by a more efficient factor input (mainly water and fertilization) and resulting decreased environmental impacts. The policy of a premium for reduced water use resulted in the highest simulated increases of total contribution margins with simultaneously reduced negative environmental impacts. However the simulation also revealed that, in order to ensure food security, incentives for producing wheat should be provided as it is the economically least profitable main crop, but it has important functions for own consumption. The simulation also revealed that policies aimed at increasing output prices of the main crops (in combination with optimized production options) can result in total higher contribution margins and decreased negative environmental impacts and higher resource use efficiency. It should be noted that the optimum results did not integrate production options which the surveyed farmers are currently applying ? this indicates that current practices are not efficient. Many studies state that knowledge transfer systems and extension services in the NCP are deficient. The survey showed that the majority of the households did not have contact with the extension services, and, moreover, most of the households never received agricultural training. A knowledge transfer program can be an efficient tool to reduce environmental impacts of farming in the NCP. In addition specific recommendations and systems under considerations of socio-economic approaches have to be developed to improve knowledge transfer and services to farmers in the NCP. Appropriate decision support systems for efficient land use in the research area have to be developed. This study showed that laws and regulations regarding environmental impacts exist, but they are not reliably enforced. Many studies state that the current institutional framework for water management is inadequate and that it, thus, represents one of the causes for the overexploitation of water resources. Therefore the responsibilities should be clearly defined in order to be able to create incentives for saving water and to increase efficiencies. Furthermore, farmers? water rights are not secure and transparent. Therefore plans, based on scientific estimations for water supply and demand, are needed to clearly define and enforce water use rights. Besides clearly defined and enforced water use rights, also longer, enforced and secure land-use rights might facilitate the adoption of sustainable farming practices. Also the institutional set-up complicates the implementation of policies. Therefore institutional change with coordinated efforts is needed. Decentralized and regionalized administrations might increase the effectiveness of policies. In addition the institutional framework has to be updated to the specific requirements in the NCP. One of the main reasons for problems related to water management is that it represents a mostly unregulated resource in the NCP. The survey showed that fertilizer use is strongly varying, overuse and undersupply occur in the research area. The strongly varying and inadequate fertilizer applications endanger the sustainability of the agricultural systems in the NCP. Furthermore the organic matter contents in the soils are too low. The survey also revealed that the farmers in the research area are not informed about the quality of their soils. Integrated into knowledge transfer programs, providing opportunities for soil analysis to the local farmers could result in fertilization practices which are based on the nutrient contents of the soil and, thus, are more efficient. Structural development projects in the Chinese rural areas need to be continued, especially in the research are, to avoid a rural exodus. The living conditions in the rural areas ? in terms of income, education and health services ? are still not comparable with the conditions in urban areas. Chinese policy has to focus on stopping the further decline of the ground water tables. Furthermore a conscious water use and environmental awareness for all stakeholders has to be created in order to avoid that pollution or resource scarcity and misuse will further reduce agricultural production in the NCP. The social costs of further decreased agricultural production in the NCP would be unbearable.
Environmental and farm management effects on food nutrient concentrations and yields of East African staple food crops
(2021) Fischer, Sahrah; Cadisch, Georg
Hidden hunger affects two billion people worldwide, particularly children and pregnant women. Human health and well-being are dependent on the quality and quantity of food consumed, particularly of plant-based foods. Plants source their nutrients from the soil. Essential nutrients for both, plants and humans, therefore, predominantly originate from the soil. Very little is known about the influence of environmental factors (e.g. soil types and abiotic factors, such as weather), or farm management choices (e.g. fertilisation or agrobiodiversity), on nutrient concentrations of edible crop parts. The main aim of this thesis was, therefore, to analyse the effects of soil fertility, farm management, and abiotic factors such as drought, on the quantity (yields) and quality (nutrient concentrations) of essential macro- (Mg, P, S, K, Ca) and micronutrients (Fe, Zn, Mn and Cu), of the edible parts of three East African staple food crops, i.e. maize (Zea mays L.), cassava (Manihot esculenta} Crantz), and matooke (East African Highland Banana (Musa acuminata Colla)), and discuss the resulting implications for food and nutrition security. Two research areas were selected in East Africa, one with a high fertility soil (Kapchorwa, Uganda - Nitisol) and one with a low fertility soil (Teso South, Kenya – Ferralsol). In each region, 72 households were randomly selected, and leaf and edible crop parts, and soil samples collected on three fields per household, organised by distance (closest, mid-distance, and farthest field). Maize and cassava were collected in Teso South, maize and matooke were collected in Kapchorwa. Yields, fertilizer usage and species richness (SR) and diversity (SD) were recorded per field. The total nutrient concentrations were measured in all samples collected (soils and plant parts). A drought occurring in the second rain season of 2016 provided the opportunity to analyse water stress effects on crop quantity and quality (Chapter 2). Edible part samples and yields collected in both seasons were compared. Soil chemical and physical properties, together with farm management variables, were compared to edible part nutrient concentrations and yields using a Canonical Correspondence Analysis (CCA) (Chapter 3). To understand the strength of association between the measurements routinely done by agronomists (leaf measurement) and nutritionists (edible part measurement), samples of each crop were collected, and were compared to each other and to yields, using a bivariate linear mixed model (Chapter 4). During the severe drought, nutrient concentrations in Kapchorwa decreased significantly from normal to drought season in both crops. In contrast, during the moderate drought in Teso South, nutrient concentrations increased significantly in both crops. Lacking nutrient phloem mobility is suggested to play a vital role in mobilisation of micronutrients (Fe, Mn, and Cu), as shown by their decreased concentration under severe drought in the yields of both crops in Kapchorwa (Chapter 2). Soil type had a very strong effect on food nutrient concentrations. Maize grain nutrient concentrations and yields, for example, were significantly higher for all nutrients measured on higher fertility soils. Maize grain had the highest correlations with soil factors. In contrast, corresponding correlations to management factors were much weaker (Chapter 3). Concerning the comparison of nutrient concentrations in different plant parts, low phloem mobile nutrients Ca, Mn, Fe, Zn, and Cu showed the largest differences in correlations between leaves and edible parts. In the same comparison, perennial crops (matooke and cassava) showed lower correlations between leaves and edible parts, than annual crops (maize) (Chapter 4). Environmental factors, such as drought impacted food nutrient concentrations. Severe drought caused a potential “double-burden” for consumers, decreasing both yields and nutrient concentrations, particularly of micronutrients. Considering food nutrient concentrations, apart from yield, as response variables in agronomic trials (e.g. fertilisation or soil improvement strategies) would contribute towards discounting the notion that crops growing on fertile soils always produce healthy and high-quality foods. Leaves may provide information on plant health, however, do not provide enough information to gauge both yields and food quality, particularly regarding micronutrients. The results also showed that measuring the edible part is vital to assessing food quality, particularly due to the observed effects of nutrient mobility, affecting particularly micronutrients and Ca. Ending hunger and improving food and nutrition security for all, particularly when confronted with global change issues such as degrading soils and a changing climate, requires a collaborative effort by all disciplines concerned.
Genotypic responses of upland rice to an altitudinal gradient
(2012) Shrestha, Suchit Prasad; Asch, Folkard
Adaptation strategies are required for crops to cope with changing climate. The impact of climate change on crop production is not straight forward to predict as extreme events comprise multiple combination of abiotic stresses and their impact differs in crop physiological growth stages. The mechanism on how new abiotic stress combinations translate into phenology and yield, and which cultivars are better adapted is yet unclear. Crop growth models are available that have been parameterized and validated for some aspects of possible climate change scenarios but in view of complex interactions crop responses to climate change are difficult to predict. On the other hand, prediction of the complex ideotype trait combinations may be interesting for breeders but physiological models are required that are well validated for the target environments. In upland rice grown under rainfed conditions without surface water accumulation methane emission is negligible and therefore greenhouse gas emission much lower compared to irrigated paddy rice systems. In addition, growing demand for rice and the increasing pressure on irrigated land leads to development of upland rice areas to supplement irrigated rice. Therefore, this study investigates genetically diverse upland rice genotypes from a wide range of origins across altitudinal gradient locations. The main objective of this study is to investigate genotypic responses of upland rice to different environments in order to calibrate crop growth models, which allow the evaluation of effects of climate change on upland rice systems. Multi-locational field (three locations: 1625, 965 and 25 m asl) trials comprising non-replicated phenological plots with five sowing dates (monthly staggered) in two consecutive years creating thirty different environments, and replicated physiological yield trials with two sowing dates (monthly staggered; early and late sowing) in two consecutive years creating twelve different environments were established in Madagascar. Ten contrasting upland rice genotypes were included in both field trials. Meteorological data were recorded on a daily basis during trial periods. Developmental stages were observed in the phenological plots; in the physiological plots yield and yield components were recorded. In addition, greenhouse trials were conducted with one upland rice genotype subjected to seven N-supply levels in a hydroponic system at the University of Hohenheim in order to understand the relationship between chlorophyll index, photochemical reflectance index and chlorophyll fluorescence parameters. Various statistical tools were applied to analyse field and greenhouse data sets. The phenological trial showed that duration to flowering was 117, 81 and 67 d in high (HA), mid (MA) and low (LA) altitudinal locations respectively. 90% of the total variance was explained by location when pooled over genotype, location, sowing dates and year. In HA, factors such as genotype, sowing date and year equally contributed to the observed variability whereas in MA year was the most determining factor and genotype had no significant contribution. Similarly, in LA sowing date was the main influencing factor and year had no significant effect. Aggregated data over locations, sowing dates and years indicated that each degree Celsius rise in mean air temperature decreased crop duration by 5 to 9 days depending upon genotype. Basic genotypic thermal constants Tbase ranged from 9.8 to 13.9 °C and Tsum from 816 to 1220 °C d within the selected genotypes. Cold tolerant genotypes were less affected by lower Tmin (14 °C) at booting to heading stage regarding spikelet sterility in HA, whereas others were highly affected at 15 °C (cold stress). Similarly, both cold sensitive and tolerant genotypes were affected by Tmax (above 30 °C) at flowering in MA and LA locations (heat stress). Grain yield and yield components were highly affected by location, year, sowing date, and genotypes and the interactions between these yield-determining factors were obvious. In HA, early sown cold tolerant genotypes had more than 5 t ha-1 grain yield and one month delay in sowing led to highly reduced yield whereas other genotypes had very poor yield on both sowing dates due to cold stress. In MA, yield difference between sowing date and genotypes was small (4.3 - 4.9 t ha-1). Grain yield in LA was vulnerable due to frequent tropical storms. Yield stability analysis showed that cold tolerant genotypes had above average stability. AMMI model for grain yield showed that environment and genotype by environment interactions were highly significant. Yield components determined during specific development stages of the genotype such as tillers per hill and percentage of filled spikelets were mainly influenced by environment, spikelets per panicle and thousand grain weight were influenced by genotype, and percentage of productive tillers was equally influenced by both genotype and environment. PCA biplots showed that all HA environments were equally influenced by all weather parameters with minimum air temperature having the strongest positive influence on genotypic performance. In all MA environments genotypic performance in all phenophases was strongly and positively influenced by rainfall, and strongly and negatively influenced by vapour pressure deficit, solar radiation and potential evapotranspiration. In the LA environments, main weather parameters influencing genotypic performance were maximum temperature and high rainfall accompanied by strong winds. The field measured SPAD values of the upper canopy leaves reflected the location specific N-remobilization and leaf senescence levels after flowering. Similarly, PRI values showed the abiotic stress responses among development stages and locations along the altitudinal gradient. These readings showed that genotypes were efficient in radiation use and N-remobilization after flowering in MA. The unsynchronized relationship between source (leaf) and sink (grain) explained the yield penalty. Emphasis on identification of morpho-physiological traits contributing to cold tolerance should be placed for further breeding. We conclude that genotypic responses of upland rice cultivars differed across altitudinal gradients. Genotypes that are well adapted in HA can easily be adapted in MA without yield decrease. But genotypes well adapted in MA may show a huge yield penalty in HA due to lower temperature during reproductive phase and consequently reduced sink formation. Frequent tropical storms and high temperature reduced yield potential in LA. Therefore, HA has a large potential for the future food security considering climate change scenarios. At present, MA is favorable for upland rice production systems, whereas LA is highly vulnerable and is expected to be even more vulnerable in future. Those results on genotype-specific responses to environmental conditions allow further improvement of crop models such as RIDEV and SAMARA (synthesis of SARRAH and EcoMeristem), which can be used to test a number of phenotypic traits x environments combinations to define ideotypes of upland rice varieties adapted to changing climate and cropping calendars. Genotypic responses of phyllochron, biomass production and crop growth rate, and radiation use efficiency across altitudinal gradients will be included to parameterize these models. In this regard, collaborations with AfricaRice, CIRAD and IRRI are ongoing.
Introducing new miscanthus hybrids into the European bioeconomy : the effect of environment and management on biomass quantity and quality
(2023) Magenau, Elena; Lewandowski, Iris
Miscanthus has been identified as a promising lignocellulosic perennial biomass crop for temperate climates and different (marginal) soils in terms of yield and ecological benefits. The cultivation of miscanthus brings numerous ecological advantages, such as a reduction in soil erosion, protection of aquatic ecosystems from alteration through eutrophication, and increasing heterogeneity in annual arable landscapes leading to increased biodiversity compared to annual crops. Reasons for this are its perenniality, the long period of time it stands on the field, and its low fertiliser and plant protection demands. Nevertheless, the area under cultivation in Europe is limited. The reasons are that the scientific yield levels are not reached commercially, and the only commercially cultivated hybrid Miscanthus × giganteus (M×g) is sterile. Miscanthus is therefore currently propagated and established via rhizomes, which limits upscaling. However, the seed-based hybrids tested so far do not reach the potential of M×g in terms of yield, quality, and ecological impact under a wide range of climatic conditions. To improve the integration of miscanthus as a biomass crop in the growing European bioeconomy, it is required to reach high and stable yields over several years (security of biomass supply) and a low ecological impact by low nutrient offtakes under different European climates. Therefore, it is essential to gain agronomic knowledge on how genetic (G), location-specific environment (E), and management (M) factors and the interactions between them affect the security of biomass supply and ecosystem services of novel seed-based hybrids. Against this background, the research objectives of this study are: 1) to investigate the effect of the onset of the growing season on biomass supply security and how it is affected by late spring frosts, 2) to assess G × E interaction effects on miscanthus biomass security, and 3) to assess G × E × M interaction effects on nutrient offtake, yield and quality of miscanthus biomass. For this purpose, new seed- and rhizome-based miscanthus hybrids were compared with the commercially grown M×g and evaluated for biomass yield, quality, and nutrient offtakes (a key parameter defining the ecological impact) under different European conditions to determine biomass supply security and ecological effects. The effect of the management parameters cutting height and harvest time was also analysed. The results show that to reach a high biomass supply security, avoiding damage by late spring frosts is essential. An effective mechanism is a low frost sensitiveness of the emerging shoots and to produce new shoots over the whole growth period, as observed for the seed-based M. sinensis × sinensis (M sin×sin). By contrast, a late emergence and producing fewer, thicker but frost-susceptible shoots at the beginning of the growing season, as observed for rhizome-based M×g and rhizome- and seed-based M. sacchariflorus × sinensis (M sac×sin), endangers the biomass supply security in case of frost after emerging. Over the first three years, the establishment process of miscanthus depended on location and hybrid. The M sin×sin hybrids flowered and senesced earlier than the taller M sac×sin hybrids. Active senescence, probably initiated by flowering, increases biomass quality by reducing the moisture and nutrient content. Following the third growing season, the highest yields were recorded at the low-altitude site in northern Italy and the lowest on a industrially damaged marginal land site in northern France. Moisture contents at spring harvest were lowest in Croatia and highest in Wales, United Kingdom. A lower moisture content is highly desirable for transport, storage and most end-use applications. Overall, lower moisture contents at harvest were found in M sin×sin hybrids than in M sac×sin. As expected, delaying the harvest until spring reduced yield and nutrient contents. At lower latitudes, the late-ripening M sac×sin combined high yields with low nutrient contents when harvested in spring. At the most elevated latitude location (Wales), the early-ripening M sin×sin combined high biomass yields with low nutrient offtakes. The M×g clone with intermediate flowering and senescence showed similarly low nutrient contents at all locations. An increased cutting height at spring harvest decreased yields by 270 kg ha-1 (0.83%) with each 1-cm increase in cutting height up to 40 cm. Although whole shoot mineral concentrations were significantly influenced by both hybrid and year interactions, total nutrient contents did not differ significantly from those in the lower basal sections. In years with wet conditions before harvest, an increase in cutting height of 10 cm decreased moisture content by up to 8%, whereas the effect during dry conditions was marginal. To achieve high biomass supply security and increased ecological benefits in miscanthus cultivation, the results of this study lead to the recommendation to cultivate M sin×sin hybrids at locations with a high risk of late spring frosts, as observed in northern European sites, and M sac×sin hybrids at locations where the risk is low, as observed in southern Europe. In southern Europe, M sac×sin hybrids achieved high yields with low nutrient and moisture contents as they made use of the long vegetation period. In general, M sin×sin has a shorter growth period than M sac×sin hybrids, making it the perfect hybrid for northern Europe, where the vegetation period is short. To ensure biomass supply in regions with extreme minimum winter temperatures and late spring frosts, miscanthus should be harvested in spring due to the thicker mulch layer, which functions as insulation. To ensure biomass supply security, a successful establishment is essential. Therefore, during the establishment phase, harvest should generally take place in spring, as the establishment period is crucial for securing biomass yield throughout the cultivation period. Weakening or even loss of plants during this period will lead to higher weed pressure and lower than optimal yields. The harvest cutting height should be as low as possible to achieve a higher yield without an over-proportional increase in nutrient offtake. However, cutting height needs to be adapted according to local conditions by finding an optimum between biomass loss and the risk of damage to harvest machinery and contamination of the biomass by soil. Should the moisture content of the biomass be too high for safe storage due to wet conditions during harvest, the cutting height can be increased to avoid costly post-harvest drying procedures. This study recommends hybrids for specific locations in Europe, provides important data for determining harvest timing and height, and key data on the ecological impact. It shows that the cultivation of miscanthus in Europe, taking into account the G × E × M interactions, has the potential to secure the biomass supply for the growing bioeconomy while positively influencing the provision of ecosystem services. Furthermore, integrating miscanthus into the agricultural system increases its resilience by diversifying the crops grown, the structure of the agricultural landscape and farmers income.
Modelling of particulate matter and ammonia emissions from German agriculture
(2016) Beletskaya, Olga; Zeddies, Jürgen
Agricultural production comes along with numerous environmental effects, such as contribution to climate change, harmful to health emission impacts as well as eutrophication and acidification of soils and waters. Political regulations and environmental protection measures at the national and international level shall support development of sustainable agriculture. The intention of this work is to analyze the alterations of particulate matter, ammonia, and greenhouse gas losses from German agriculture arising due to adaptations in agricultural and environmental policy, and to find out efficient PM and NH3emission abatement options. To show, how certain economic and political conditions and their adjustment over time do affect amount of NH3, PM, and GHG released from agriculture and to evaluate emission mitigation options, economic-ecological static integer linear model, EFEM (Economic Farm Emission Model), has been developed. Following exogenous parameters have been integrated into the model: emission factors and the activities data stemming from FADN (Farm Accountancy Data Network) and census databases. In EFEM farm structure, production activities and extrapolation tool are represented in the system of interrelated modules for five farm types, i.e., arable farms, forage-growing, mixed and intensive livestock farms (one with the emphasises on pig husbandry and another one specializing in poultry production). The modelling is done for three German counties and each of them has focus regions, which are exemplary for important sources of PM, NH3, and GHG emissions in agriculture. Thus, following study regions have been chosen: Baden-Württemberg characterized by forage growing prevailing there, Lower Saxony marked by intensive livestock productions and Brandenburg due to its sandy arable sites at risk of erosion. The individual scenarios analyse abatement and financial efficiency of the adjustments of emission sources. Emission sources are adjusted in the framework of the emission relevant agricultural production practice, as exclusion of urea from mineral fertilization practices, switching from slurry to solid manure based livestock housing systems, introduction of crude protein reduced feeding by pigs and poultry, environmentally friendly slurry storage and land application, reduced tillage, and installation of exhaust air treatment systems in pig barns. Relatively efficient abatement of NH3 results from the exclusion of urea from fertilization practice at farms and in regions with higher land endowments, the switch from liquid to solid manure based housing system for cattle and the injection of liquid manure into the soil and covering manure storage with granulate at farms and in regions with comparatively high livestock density. Efficient PM and GHG emission reductions, mainly due to carbon sequestration, follows the introduction of the reduced tillage. Installation of Exhaust Air Treatment Systems, such as one-stage and multiple-stage chemical scrubbers, results in relatively expensive but more efficient measure for the reduction of both NH3 and PM losses. Net benefit, as the difference between reduced costs of damage for human health and environment and mitigation costs, gives the insight into the effect of abatement measure for the overall economy. Among all scenarios analysed in this study, the emission abatement options assuring maximal net benefits and emissions reduction are combined together and suggested as the abatement strategy at the farm and policy level. The scenario results are compared with national emission abatement ratios proposed by the European Commission for the years between 2020 and 2029. However, this efficiency of each individual abatement measure varies for study regions due to their individual conditions. Increasing attention to environmental problems at the regional and global level requires higher contribution of scientists from all over the world to the definition of pollution and emission abatement status. This study demonstrates the relevance of further investigation of PM and NH3 emissions in and from agriculture and of the ways to abate them.
Perception for context awareness of agricultural robots
(2018) Reiser, David; Griepentrog, Hans
Context awareness is one key point for the realisation of robust autonomous systems in unstructured environments like agriculture. Robots need a precise description of their environment so that tasks could be planned and executed correctly. When using a robot system in a controlled, not changing environment, the programmer maybe could model all possible circumstances to get the system reliable. However, the situation gets more complex when the environment and the objects are changing their shape, position or behaviour. Perception for context awareness in agriculture means to detect and classify objects of interest in the environment correctly and react to them. The aim of this cumulative dissertation was to apply different strategies to increase context awareness with perception in mobile robots in agriculture. The objectives of this thesis were to address five aspects of environment perception: (I) test static local sensor communication with a mobile vehicle, (II) detect unstructured objects in a controlled environment, (III) describe the influence of growth stage to algorithm outcomes, (IV) use the gained sensor information to detect single plants and (V) improve the robustness of algorithms under noisy conditions. First, the communication between a static Wireless Sensor Network and a mobile robot was investigated. The wireless sensor nodes were able to send local data from sensors attached to the systems. The sensors were placed in a vineyard and the robot followed automatically the row structure to receive the data. It was possible to localize the single nodes just with the exact robot position and the attenuation model of the received signal strength with triangulation. The precision was 0.6 m and more precise than a provided differential global navigation satellite system signal. The second research area focused on the detection of unstructured objects in point clouds. Therefore, a low-cost sonar sensor was attached to a 3D-frame with millimetre level accuracy to exactly localize the sensor position. With the sensor position and the sensor reading, a 3D point cloud was created. In the workspace, 10 individual plant species were placed. They could be detected automatically with an accuracy of 2.7 cm. An attached valve was able to spray these specific plant positions, which resulted in a liquid saving of 72%, compared to a conventional spraying method, covering the whole crop row area. As plants are dynamic objects, the third objective of describing the plant growth with adequate sensor data, was important to characterise the unstructured agriculture domain. For revering and testing algorithms to the same data, maize rows were planted in a greenhouse. The exact positions of all plants were measured with a total station. Then a robot vehicle was guided through the crop rows and the data of attached sensors were recorded. With the help of the total station, it was possible to track down the vehicle position and to refer all data to the same coordinate frame. The data recording was performed over 7 times over a period of 6 weeks. This created datasets could afterwards be used to assess different algorithms and to test them against different growth changes of the plants. It could be shown that a basic RANSAC line following algorithm could not perform correctly under all growth stages without additional filtering. The fourth paper used this created datasets to search for single plants with a sensor normally used for obstacle avoidance. One tilted laser scanner was used with the exact robot position to create 3D point clouds, where two different methods for single plant detection were applied. Both methods used the spacing to detect single plants. The second method used the fixed plant spacing and row beginning, to resolve the plant positions iteratively. The first method reached detection rates of 73.7% and a root mean square error of 3.6 cm. The iterative second method reached a detection rate of 100% with an accuracy of 2.6 - 3.0 cm. For assessing the robustness of the plant detection, an algorithm was used to detect the plant positions in six different growth stages of the given datasets. A graph-cut based algorithm was used, what improved the results for single plant detection. As the algorithm was not sensitive against overlaying and noisy point clouds, a detection rate of 100% was realised, with an accuracy for the estimated height of the plants with 1.55 cm. The stem position was resolved with an accuracy of 2.05 cm. This thesis showed up different methods of perception for context awareness, which could help to improve the robustness of robots in agriculture. When the objects in the environment are known, it could be possible to react and interact smarter with the environment as it is the case in agricultural robotics. Especially the detection of single plants before the robot reaches them could help to improve the navigation and interaction of agricultural robots.