Jürgen Schellberg

• Retired
• University of Bonn

Precise and timely information on biomass yield and nitrogen uptake in intensively managed grasslands are essential for sustainable management decisions. Imaging sensors mounted on unmanned aerial vehicles (UAVs) along with photogrammetric structure-from-motion processing can provide timely data on crop traits rapidly and non-destructively with a h...

Remote sensing systems based on unmanned aerial vehicles (UAVs) are well suited for airborne monitoring of small to medium-sized farmland in agricultural applications. An imaging system is often used in the form of a multispectral multi-camera system to derive well-established vegetation indices (VIs) efficiently. This study investigates the potent...

Vegetation equilibrium reflects the long-term stable ecological conditions. However, the equilibrium in guild composition is a dynamic one, continually perturbed by climate. The changes in plant species composition in the Rengen Grassland Experiment, Germany (established in 1941) were studied over a 10-year period (2005-2014). It is a complete rand...

Temporal trend in unfertilized control was probably caused by an ongoing oligotrophication. It seems that vegetation equilibrium in all fertilized treatments was caused by stabile nutrient level in the soil. Species rich swards were only maintained in the unfertilized (A), limed (B) and limed with N fertilization treatments (C) through long-term pe...

Monitoring and predicting above ground biomass yield of grasslands are of key importance for grassland management. Established manual methods such as clipping or rising plate meter measurements provide accurate estimates of forage yield, but are time consuming and labor intensive, and do not provide spatially continuous data as required for precisi...

Globally, drought constitutes a serious threat to food and water security. The complexity and multivariate nature of drought challenges its assessment, especially at local scales. The study aimed to assess spatiotemporal patterns of crop condition and drought impact at the spatial scale of field management units with a combined use of time-series f...

Questions Fertilizer application is a key driver affecting the diversity and conservation value grassland vegetation. Using a long‐term fertilization experiment in mountain grassland we addressed the following questions: i) what is the effect of long‐term fertilizer applications on species richness and plant species composition, and ii) is there an...

Forage monitoring in grassland is an important task to support management decisions. Spatial data on (i) yield,(ii) quality, and (iii) floristic composition are of interest. The spatio-temporal variability in grasslands is significant and requires fast and low-cost methods for data delivery. Therefore, the overarching aim of this contribution is th...

Grass growth and utilisation on grassland farms across the UK and Ireland are below their potential, and nutrient management is sub-optimal. Excessive soil phosphorus concentrations are an issue, contributing to eutrophication of waterways, while sub-optimal soil pH due to a reduction in lime use is seen in many areas. This paper discusses the pote...

Grassland functional diversity and management for enhancing ecosystem services and reducing environmental impacts: A cross-scale analysis

Non-destructive methods to derive spatial information on the development of forage mass are of key importance in managed grasslands. Established methods are rising plate meter (RPM) and rapid pasture meter, which both require in-field work, are rather time consuming, and do not provide spatially continuous data. Therefore, the overall objective of...

Climate change, food insecurity and limited land and water resources strengthen the need for operational and spatially explicit information on vegetation condition and dynamics. The detection of vegetation condition as well as multiannual and seasonal changes using satellite remote sensing, however, depends on the choice of data including length an...

Alpine landscapes are characterized by extreme topography and climate conditions with grassland occurring at sites higher than 2,000m a.s.l. For alpine grassland ecosystems, temperature is the most limiting environmental factor for growth. We hypothesized, that the expression of morphological plant functional traits reveals variation in growth rate...

To examine the variability of plant species composition and main functional groups, vegetation data collected in the Rengen Grassland Experiment in the Eifel Mountains (Germany) in the years 2005-2014 were evaluated. The experiment was established in 1941. It is a complete randomised block design with five treatments and five replicates. The treatm...

Generally, the cover (%) variability of the main functional groups (with the exception of legumes) such as short forbs, tall forbs and tall grasses were relatively low in all treatments and spatio-temporal changes in the sward were mainly caused by the cover (%) variability of individual plant species.

Radiation Use Efficiency (RUE) defines the productivity with which absorbed photosynthetically active radiation (APAR) is converted to plant biomass. Readily used in crop growth models to predict dry matter accumulation, RUE is commonly determined by elaborate static sensor measurements in the field. Different definitions are used, based on total a...

Accurate classification and mapping of crops is essential for supporting sustainable land management. Such maps can be created based on satellite remote sensing; however, the selection of input data and optimal classifier algorithm still needs to be addressed especially for areas where field data is scarce. We exploited the intra-annual variation o...

Proper parameterisation and quantification of model uncertainty are two essential tasks in improvement and assessment of model performance. Bayesian calibration is a method that combines both tasks by quantifying probability distributions for model parameters and outputs. However, the method is rarely applied to complex models because of its high c...

Monitoring the spectral response of intensively managed grassland throughout the growing season allows optimizing fertilizer inputs by monitoring plant growth. For example, site-specific fertilizer application as part of precision agriculture (PA) management requires information within short time. But, this requires field-based measurements with hy...

Great technological advances have been made in Precision Agriculture (PA) in the past decade, yet adoption of PA in intensive grassland areas in North West Europe is low. This is despite the fact that in these areas the market structures are suitable and there are highly developed agricultural and food industries offering great potential for the ap...

Accurate agricultural land use (LU) map is essential for many agro-environmental applications. With advances in technology, object-based image classification and non-parametric machine learning algorithms evolved. Still, no particular method has universal applicability. This paper compares robust non-parametric machine learning algorithms, random f...

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Monitoring the reaction of grassland canopies on fertilizer application is of major importance to enable a well-adjusted management supporting a sustainable production of the grass crop. Up to date, grassland managers estimate the nutrient status and growth dynamics of grasslands by costly and time-consuming field surveys, which only provide low te...

In rangelands, grazing management is a main driver of rangeland condition. Due to masking effects of seasonal climate fluctuations, little is known about (dis)similarity of management effects on rangeland condition and forage provision across major dryland biomes. Taking a macro-ecological perspective, we analysed if management effects differed bet...

An accurate agricultural land use map is an essential input for many agro-environmental applications such as crop, irrigation and land management. Enhancement of the accuracy of remote sensing based land use maps is still an ongoing process, since the development of the first classification algorithms for satellite datasets in the 1970s. With the r...

The critical nitrogen concentration (CNC) is a simple yet robust relationship that describes the changes in crop N during growth. In Reyes et al. (Agron Sustain Dev 35:1561–1570, 2015), we applied the concept of CNC to calculate N uptake across various cutting regimes. While it is well-established that decreasing cutting frequency changes growth ra...

henomapping is an approach which allows the derivation of spatial patterns of vegetation phenology and rangeland productivity based on time series of vegetation indices. In our study, we propose a new spatial mapping approach which combines phenometrics derived from high resolution (HR) satellite time series with spatial logistic regression modelin...

Remote sensing of crop biomass is important in regard to precision agriculture, which aims to improve nutrient use efficiency and to develop better stress and disease management. In this study, multi-temporal crop surface models (CSMs) were generated from UAV-based dense imaging in order to derive plant height distribution and to determine forage m...

Remote sensing of crop biomass is important in regard to precision agriculture, which aims to improve nutrient use efficiency and to develop better stress and disease management. In this study, multi-temporal crop surface models (CSMs) were generated from UAV-based dense imaging in order to derive plant height distribution and to determine forage m...

An accurate agricultural land use map is essential for many agro-environmental assessments such as irrigated water management. Enhancement of the accuracy of remote sensing based land use maps is still an ongoing process, since the development of the first classification algorithms for satellite datasets in the 1970s. With the rapid advances in com...

An accurate agricultural land use map is essential for many agro-environmental assessments such as irrigated water management. Enhancement of the accuracy of remote sensing based land use maps is still an ongoing process, since the development of the first classification algorithms for satellite datasets in the 1970s. With the rapid advances in com...

There are still a few long-term experiments in grassland existing in Europe. Some of them have been established even more than hundred years ago. Despite limited resources, maintenance and continuation of these valuable experiments seem to be of great importance. Numerous research questions can today be worked on by using developed laboratory techn...

Grassland covers about one quarter of the Earth’s land area and is currently estimated to contribute to the livelihoods of over 800 million people. Grassland provides ecosystem goods and services, mainly through the provisioning of milk and meat. Therefore, the proper use of grasslands will be essential for feeding the nine billion people that will...

Die Entwicklungsdynamik von Pflanzenbeständen wird von zahlreichen Bewirtschaftungs- und Standortfaktoren beeinflusst. Die laufende Beobachtung dieser Dynamik setzt voraus, dass der Bestand nach jeder Datenerhebung unbeeinflusst und ohne Beeinträchtigung sein Wachstum fortsetzen kann. Mit der Spektrometrie als berührungslose Erfassungsmethode kann...

The nitrogen (N) dilution curve is a useful tool for farmers to assess the effectiveness of fertilizer application. The N dilution curve describes the decrease in plant N as biomass increases. This concept has not yet been tested for its applicability and robustness under different cutting regimes in grasslands. We conducted a principal components...

In this paper, we drew on experience from current Earth Observation (EO) research in Africa and Asia based on the 250m MODIS vegetation index time series covering large spatial extents. In the first example in the southern Africa, we derived a key set of phenometrics (overall greenness, peak and timing of annual greenness) and analyzed trends in th...

Image time series of high temporal and spatial resolution capture land surface dynamics of heterogeneous landscapes. We applied the ESTARFM (Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model) algorithm to multi-spectral images covering two semi-arid heterogeneous rangeland study sites located in South Africa. MODIS 250 m resolution an...

Acquiring multi-temporal spatial information on vegetation condition at scales appropriate for site-specific agricultural management is often complicated by the need for meticulous field measurements. Understanding spatial/temporal crop cover heterogeneity within irrigated croplands may support sustainable land use, specifically in areas affected b...

Monitoring land surface phenology from satellites is essential for characterizing vegetation dynamics over large areas. Availability of very high spatial resolution image time series from RapidEye satellite constellations allow the phenology analysis also at field level, which is especially important for fragmented landscapes such as in South Afric...

Monitoring land surface phenology from satellites is essential for characterizing vegetation dynamics over large areas. With the current advances in satellite remote sensing, availability of very high spatial resolution image time series makes it possible to map phenology also at field level, which is especially important for fragmented landscapes...

In southern Africa, increased frequency and intensity of extreme climatic events in combination with anthropogenic pressures have been causing major changes in vegetation cover and productivity. Deterioration of vegetation and thus land productivity adversely affects the ability of agro-ecological systems to render important ecosystem services. Kno...

We have tried to illustrate the links between multiple functions and traits of grassland on the one hand and ecosystem services (ES) on the other. The bio-physical structure of organism communities can be described as the composition and organisation of functional traits of soil, plant and animal. These traits are strongly interacting, with differe...

Despite our growing knowledge on plants' functional responses to grazing, there is no consensus if an optimum level of functional aggregation exists for detecting grazing effects in drylands. With a comparative approach we searched for plant functional types (PFTs) with a consistent response to grazing across two areas differing in climatic aridity...

Questions Plant communities fulfil key functions in the ecosystem, which can be characterized by their plant functional traits. In functional ecology, plant communities are considered to hold a set of trait attributes reflecting a specific plant strategy adapted to persist in the environment to which they are exposed. In semi‐arid grasslands of the...

Grassland scientists and farmers are increasingly faced with emerging new technologies and information systems that have been primarily developed in engineering sciences, in particular, precision agriculture, remote sensing, geographic information and biotechnology. Judgment upon whether the implementation of any of these technologies may be benefi...

In South African grasslands, rangeland management is strongly related to land tenure. Communal farms are reported to exhibit less desirable vegetation conditions for livestock than commercial farms. Time series of high spatial and temporal resolution imagery may be useful for improved evaluation of these rangelands as they provide information at a...

The Steinach Grassland Experiment (SGE) is probably the oldest still-running grassland fertilizer experiment in Continental Europe. It was established on an alluvial Alopecurus pratensis meadow in southeast Germany in 1933. The aim of this study was to provide detailed information on this experiment concerning the effects of decades-long nitrogen,...

Declining global P reserves require a better understanding of P cycling in soil and related plant uptake. On managed grasslands, application of lime and fertilizer affects not only soil nutrient status, but also plant-species composition of the sward. We examined the P fractionation in the Rengen Grassland Experiment (RGE) on a naturally acid Stagn...

Introduction: Land degradation in South African rangelands has frequently been studied in the context of tenure systems, because both governmental policy and range management practices were historically implemented in contrasting forms. We compared the functional response of vegetation along grazing gradients between a communal (CU) and commercial...

Polyploidy and increased genome size are hypothesized to increase organismal nutrient demands, namely of phosphorus ( P ), which is an essential and abundant component of nucleic acids. Therefore, polyploids and plants with larger genomes are expected to be selectively disadvantaged in P‐limited environments. However, this hypothesis has yet to be...

Precision-farming applications are mainly based on site-specific information of soil properties at the field scale. For this purpose, a number of novel sensor techniques have been developed but not intensively tested under different field conditions. This study presents a combined application of a self-developed dual-sensor vertical penetrometer (D...

The traditional way of interpreting environmental and management effects on floristic composition based on phyto‐sociological classification is increasingly accompanied by a trait‐based approach. Plant functional traits (PFT) enable us to link morphological, physiological and phenological plant properties to their functions. Recent research on PFT...

Despite their wide range of applications, process-based plant (crop and grassland) growth models often fail to reproduce yields, particularly at farm, regional and larger scales. This is largely due to inadequate information about field management activities needed as input to these models. A promising approach to overcome this limitation is to lin...

The aim of this study was to determine the effects of different long-term management options on re-establishment of traditional species-rich grassland in a Lolio-Cynosuretum grassland. The experiment was set up in 1987 in a low-fertilized mown pasture in the Eifel Mountains (Germany). Two and four cuts per year each with three levels of nitrogen fe...

Rhinanthus minor (yellow-rattle) can be used for restoration of species-rich grasslands but is vulnerable to competitive exclusion from high total aboveground biomass production of vascular plants. We asked (1) whether there is a threshold limit for total annual aboveground biomass production of vascular plants above which R. minor cannot establish...

Increased nutrient availability is generally believed to be harmful for terrestrial orchids. However, no information is available on whether grassland orchids survive decades-long calcium (Ca), nitrogen (N), phosphorus (P) and potassium (K) application. We took advantage of sampling in one of the oldest long-term experiments in the world, the Renge...

Ryegrass (Lolium perenne L.) in grassland is known to sustain with water and nitrogen (N). This study investigates biomass and N partitioning in plant organs (roots, main and the youngest tillers) under water-nitrogen interactions. Nitrogen was applied at the rates of 50 and 100 mg N kg−1 as N1 (low N) and N2 (high N) treatments, respectively, with...

The Rengen Grassland Experiment (RGE) was established in the Eifel Mountains (Germany) on a low productive Nardetum in 1941. Since then, the following fertilizer treatments have been applied with a late two-cut system: unfertilized control, Ca, CaN, CaNP, CaNPKCl and CaNPK2SO4. We aimed to understand how concentrations of macro (N, P, K, Ca and Mg)...

Information on available diversity and drought resistance among Chloris gayana accessions would offer considerable potential to select genotypes to alleviate the feed inadequacy that constrains livestock production in dry tropical areas. A collection of 62 C. gayana accessions from the genebank of the International Livestock Research Institute in E...

The Rengen Grassland Experiment (RGE), set up on a Nardus grassland in 1941, consists of a control and five fertilizer treatments (Ca, CaN, CaNP, CaNP-KCl and CaNP-K2SO4). In 2005, soil chemical properties were analyzed to investigate the effect of soil variables on biomass production, plant species composition and species richness of vascular plan...

Sustainable rangeland management is an important issue not only in semi-arid areas but also in sub-tropical regions. For optimal utilization and protection of natural resources, spatial information on the current state and grazing intensity are required. In this paper the integration possibilities of remote sensing derived information for an optimi...

Question: Is there any effect of cutting frequency and liming on P and K availability in the soil, biomass production and plant species composition after cessation of fertilizer application? Location: Eifel Mountains, SW Germany. Methods: The long-term Grassland Extensification and Nutrient Depletion Experiment was established on a fertilized and m...

Tracing back the N use efficiency of long-term fertilizer trials is important for future management recommendations. Here we tested the changes in natural N-isotope composition as an indicator for N- management within a long-term fertilization lysimeter experiment in a low mountain range pasture ecosystem at Rengen (Eifel Mountains), Germany. Cattl...

The Rengen Grassland Experiment in Germany, established in 1941, consists of the following fertilizer treatments applied under a two cut management: control, Ca, CaN, CaNP, CaNP-KCl, and CaNP-K(2)SO(4). The aim of this study was (1) to identify effects of fertilizer application on biomass and species composition of bryophytes and (2) to investigate...

Question: How does semi-natural grassland diversify after 65 years of differential application of Ca, N, P, and K fertilizers? Is fertilizer application adequately reflected by the Ellenberg indicator values (EIVs)? Location: Eifel Mountains, West Germany. Methods: The Rengen Grassland Experiment (RGE) was established in an oligotrophic grassland i...

As an extension in precision agriculture, it utilizes various high techniques to manage soil and water resources in pasture environment. However, the pastureland, which is different from arable field, does not allow the on-the-go survey with multi-sensor system because of the physical destruction in the field. This study used an innovated dual-sens...

Precision agriculture (PA) is an innovative, integrated and internationally standardized approach aiming to increase the efficiency of resource use and to reduce the uncertainty of decisions required to control variation on farms. Worldwide, investments in research and technology on PA have considerably increased during the past decades. Advances i...

There is evidence that unequal slurry application on agricultural land contributes to N losses to the environment. Heterogeneity within fields demands adequate response by means of variable rate application. A technique is presented which allows site-specific application of slurry on grassland and arable land based on pre-defined application maps....

The Rengen Grassland Experiment (RGE) was established in the Eifel Mts. (Germany) on a low productive Nardetum in 1941. Since then, the following fertiliser treatments have been applied along with a two cut system: unfertilised control, Ca, CaN, CaNP, CaNP–KCl and CaNP–K2SO4 with basic slag (syn. Thomas phosphate) as the only P fertiliser. The effe...

The release of nitrogen on pastures by the grazing animal is a significant source of N load to soil and water and hence a possible source of nitrate pollution. Here we studied the effect of forage quantity and quality related to N intake to examine excretion and loss. A two-year grazing experiment on an intensively managed Lolio-Cynosuretum was est...

A long-term fertilizer experiment (the Rengen Grassland Experiment, RGE) was established in 1941 in the Eifel Mountains of Germany on low productive grassland naturally dominated by Calluna vulgaris and Nardus stricta. Six treatments combinations of Ca, N, P, and K fertilizer were applied annually: an unfertilized control, Ca, CaN, CaNP, CaNP–KCl,...

A set-aside experiment on sub-alpine Nardo-Caricion rigidae grassland was identified in the Giant Mts. (Krkonoše, Karkonosze), in which Ca, N and P fertilizers were each applied at three rates on five occasions from 1965 to 1967; since that time plots remained abandoned. In 2004, the effect of all fertilized treatments on sward structure was still...

Digital image processing has the potential to support the identification of plant species required for site-specific weed control in grassland swards. The present study focuses on the identification of one of the most invasive and persistent weed species on European grassland, the broad-leaved dock (Rumex obtusifolius L., R.o.), in complex mixtures...

The potential release of nutrients from animal farms into soil, water and the atmosphere is a major concern in agronomy. Farm gate balances are widely utilised to validate the compatibility of a farming system to the surrounding environment, although they do not reveal the internal nutrient flow as influenced by production intensity and hence might...

The potential release of nutrients from animal farms into soil, water and the atmosphere is a major concern in agronomy. Farm gate balances are widely utilised to validate the compatibility of a farming system to the surrounding environment, although they do not reveal the internal nutrient flow as influenced by production intensity and hence might...

Increased climatic variability and more frequent episodes of extreme conditions may result in crops being exposed to more than one extreme temperature event in a single growing season and could decrease crop yields to the same extent as changes in mean temperature. The developmental stage of the crop exposed to increased temperatures will determine...

A long-term fertilizer experiment, which was set up in 1941 on extensively grazed heathland, naturally dominated by Calluna vulgaris L. and Nardus stricta L., is presented. The turf layer was grubbed and reseeded with a grass/legume mixture, and plots were fertilized with (a) lime only as calcium (including magnesium), (2) lime and nitrogen (Ca/N),...

Grass vegetative growth is highly dependent on water and nitrogen (N) availability. The objective of the experiment was to examine the effect of partial drought under two different N levels on leaf growth and development at various nodal position of the plant. Irrigated versus non irrigated treatment significantly influenced leaf area development o...

Auf dem Versuchsgut Dikopshof nahe Bonn wurde im Jahr 1904 ein Statischer Dauerdüngungsversuch mit den Fruchtarten der “Rheinischen Fruchtfolge”; (Zuckerrüben/Weizen/Roggen/Klee/Hafer) angelegt. Im Jahr 1953 wurde die Fruchtart Hafer durch Kartoffeln ersetzt. In einer Hälfte der Versuchsfläche sind ungedüngte und vollgedüngte Parzellen den N‐, P‐,...

Un modèle simple de réflectance spectrale est proposé. Il permet de simuler des spectres de feuilles à partir de la concentration en chlorophylle et des niveaux de réflectance dans l'infrarouge. Un modèle dérivé ne prenant en compte que la concentration en chlorophylle permet de simuler la réflectance des feuilles dans les bandes larges d'un densitomè...

The Rengen Grassland Experiment (RGE), begun on grassland dominated by Nardus stricta in 1941, is one of the oldest properly designed still running fertiliser experiment worldwide. RGE consisted of following treatments arranged in five randomised blocks: an unfertilized control, Ca, CaN, CaNP, CaNP-KCl, and CaNP-K 2 SO 4 . In 2005, soil chemical pr...