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July 1993 - September 2001
Publications
Publications (160)
This paper describes the dataset that was used to test the reliability of eight crop models in simulating growth and yield of canola in response to sowing dates, nitrogen inputs and climate variability across five countries. The dataset includes four spring cultivars and three winter cultivars across six sites, which represents a diverse range of c...
Multi-environmental trials (MET) with temporal and spatial variance are crucial for understanding genotype-environment-management (GxExM) interactions in crops. Here, we present a MET dataset for winter wheat in Germany. The dataset encompasses MET spanning six years (2015–2020), six locations and nine crop management scenarios (consisting of combi...
Background
Root growth is most commonly determined with the destructive soil core method, which is very labor-intensive and destroys the plants at the sampling spots. The alternative minirhizotron technique allows for root growth observation throughout the growing season at the same spot but necessitates a high-throughput image analysis for being l...
In recent decades, extensive research has focused on estimating winter wheat yields and developing methods for collecting the necessary field data. However, it may be advantageous to first evaluate which data types and levels of model complexity are truly essential. This study examined the explanatory power of water regime modeling, the green area...
Continuous wheat cropping often leads to yield decline, with suspected causes including increased pathogen susceptibility, decreased root growth, or low nutrient use efficiency, though the exact causes remain unknown. Here, we investigated soil and root-associated bacterial and archaeal communities in wheat under rotation versus continuous cultivat...
Poster will be shown at the BonaRes Conference in Leipzig (28.-30.5.2024) and at the DLG Field Days (June 2024)
Cover crops (CC) can contribute to climate protection as a result of their effects on soil nitrogen (N) cycling and nitrous oxide (N 2 O) emission and by increasing soil organic carbon (SOC) stocks. This study explored the influence of different winter CC (saia oat, winter rye and spring vetch) compared with bare fallow, followed by silage maize on...
The fast and accurate provision of within-season data of green area index (GAI) and total N uptake (total N) is the basis for crop modeling and precision agriculture. However, due to rapid advancements in multispectral sensors and the high sampling effort, there is currently no existing reference work for the calibration of one UAV (unmanned aerial...
Understanding the interactions between nitrogen mineralization in soil and site-specific environmental factors is essential for developing tailored nitrogen management approaches in intensive agricultural systems. This study assesses the potential of residue management strategies to mitigate nitrogen leaching losses, focusing specifically on winter...
The low nitrogen (N)-use efficiency of intensive winter oilseed rape (WOSR) cropping systems may cause negative environmental impacts, especially due to N leaching and gaseous losses. The aim of this study was to use data from field experiments (five sites across Germany representing typical WOSR regions) for parametrization of a nitrous oxide (N2O...
Significant greenhouse gas emissions during substrate cultivation reduces the potential environmental benefits of biogas production. This study investigates the productivity of different cropping systems and their environmental impact in terms of nitrous oxide (N2O) emissions under the environmental conditions of the coastal marsh regions (Northern...
In cereal crops, environmental fluctuations affect different physiological processes during various developmental phases associated with the formation of yield components. Because these effects are coupled with cultivar-specific phenology, studies investigating environmental responses in different cultivars can give contradictory results regarding...
Yield decline in wheat grown after wheat is frequently attributed to fungal disease occurrence, but it is also found without visible disease infection. Thus it is hypothesized that other factors such as N supply or soil structural degradation may lead to wheat yield decline when grown after wheat. The aims of this study were to analyze if (i) the c...
Cover crops (CCs) are known for their multiple benefits in agro-ecosystems. This is especially true in intensive cropping systems with high nitrogen (N) inputs and considerable post-harvest residual N. Furthermore, research has shown that CCs have the potential to reduce nitrate N leaching losses. The efficacy of ecosystem services by implementing...
Nitrogen (N) loss by leaching is a major concern in common crop rotations in Central Europe due to high post-harvest soil mineral N, low N uptake in autumn/winter, and percolation. This can lead to eutrophication of water bodies and indirect greenhouse gas emissions. One potential solution is to control microbial immobilization through the incorpor...
https://authors.elsevier.com/a/1gZAdB8ccySqK
It is common practice in agriculture to apply high‑carbon amendments, e.g. straw, or nitrification inhibitors (NI) to reduce soil nitrogen (N) losses. However, little is known on the combined effects of straw and NI and how seasonal soil temperature variations further affect N immobilization. We conduct...
Agriculture is a major contributor to nitrate groundwater contamination. Hence, farmers are demanded to reduce the environmental impact but simultaneously must provide sufficient food products. One important building block for this “sustainable intensification” are appropriate cropping strategies. The potential of modified crop rotations was evalua...
Recently the application of spectral reflection data for the prediction of crop parameters for applications in precision agriculture, such as green area index (GAI), total aboveground dry matter (DM), and total aboveground nitrogen content (N content) increases. However, the usability of vegetation indices (VI) for the prediction of crop parameters...
Cover crops are known to provide beneficial effects to agricultural systems such as a reduction in nitrate leaching, erosion control, and an increase in soil organic matter. The monitoring of cover crops’ growth (e.g., green area index (GAI), nitrogen (N) uptake, or dry matter (DM)) using remote sensing techniques allows us to identify the physiolo...
Information on the responsiveness of winter barley to nitrogen (N) is scarce. Based on a long-term field trial (1978–2015) with different winter barley varieties in northern Germany combined with 64 N fertilizer treatments differing in amount (0–360 kg N ha⁻¹) and distribution, the effects of N fertilizer amount and variety on the grain yield and i...
To better understand how climate change might influence global canola production, scientists from six countries have completed the first inter-comparison of eight crop models for simulating growth and seed yield of canola, based on experimental data from six sites across five countries. A sensitivity analysis was conducted with a combination of fiv...
Die Festschrift zeichnet die Entwicklung der Agrar- und Ernährungswissenschaftlichen Fakultät der Christian-Albrechts-Universität zu Kiel von ihrer Vorgeschichte bis zur Gegenwart nach. Gezeigt wird der Wandel der Instituts- und Forschungsstruktur ebenso wie der Weg vom einstigen Landwirtschafts- zum heutigen Bachelor- und Masterstudium der Agrar-...
Greenhouse gas (GHG) emissions as well as other gaseous emissions and agronomic variables were measured for three years (2011/2012 - 2014/2015) at eight experimental field sites in Germany. All management activities were consistently documented. The database (GHG-DB-Thuenen) stores these multi-variable data sets of gas fluxes (CO2, N2O, CH4 and NH3...
The concept of the critical nitrogen (Ncrit) dilution curve and the derived NNI is generally accepted and used for many crops to describe the crop N status during vegetative growth. Based on field trials with different N treatments carried out in northern Germany, we identified Ncrit curves based on shoot DM, leaf DM and stem DM for winter wheat (2...
In den vergangenen Jahren/Jahrzehnten haben sich Anbausysteme mit stark verengten Fruchtfolgen und Selbstfolgen etabliert, deren Nachteile jedoch zunehmend sichtbar werden. Insbesondere das in Norddeutschland weit verbreitete Blattfrucht Winterraps bietet mit vergleichsweise geringer Stickstoff-(N)-Effizienz Potential zur Verbesserung der Nachhalti...
Winter oilseed rape (WOSR) is Europe’s prime oilseed crop and is grown for biofuel and edible oil production. To investigate the effects of climate change on the yield of winter oilseed rape, two crop models (HERMES and HUME-OSR) were used. This study investigated the sensitivity of crop model parameters (as a proxy of plant traits) under climate c...
Das Verbundprojekt „Quantifizierung und Minderung von Ammoniak-Emissionen nach Mineraldünger (NH3-Min)“ verfolgt das Ziel, Ammoniakemissionen bei der Applikation synthetischer Stickstoffdünger zu reduzieren und die Stickstoffeffizienz zu steigern. Zum Erreichen dieses Ziels werden in Kiel (Standort Nord) Parzellenversuche mit unterschiedlichen Düng...
After the harvest of winter oilseed rape and faba bean crops, considerable high soil nitrate values may be built up before winter in central to north European regions. High precipitation and a low N uptake by the subsequent crop in fall cause a high risk of N2O emissions and nitrate leaching. Microbial decomposition of crop residues or high carbon...
An approach of exploiting and assessing the potential of Sentinel-2 data in the context of precision agriculture by using data from an unmanned aerial vehicle (UAV) is presented based on a four-year dataset. An established model for the estimation of the green area index (GAI) of winter wheat from a UAV-based multispectral camera was used to calibr...
A high recovery of applied fertilizer nitrogen (N) is required to minimize the environmental impact and to achieve high grain protein concentrations (GPC). Based on a long-term field trial (1976–2018) with winter wheat in northern Germany with 64 N fertilizer treatments differing in amount (0–360 kg N ha⁻¹) and distribution, the effects of N fertil...
https://www.frontiersin.org/research-topics/9696/exploring-gxexm-synergies-in-world-wide-wheat-production-and-the-opportunities-for-international-col
The present study investigated genotypic differences in canopy temperature of 218 testcross progenies of a recombinant inbred lines mapping population of winter rye. For this purpose, we repeatedly measured canopy temperature (Tc) and air temperature (Ta) differences (Tc − Ta) in field trials on two locations with sandy soils in northern Germany, t...
The aim of this study was to quantify site-specific levels of indirect nitrous oxide (N2O) emissions from oilseed rape (OSR) cropping in Germany, resulting from ammonia (NH3) volatilization after organic fertilizer application and nitrate (NO3⁻) leaching based on measurement in field experiments and additional simulation modelling. In field experim...
Autumn-sown, non-bolting winter beets may show a faster canopy formation in spring. In order to estimate their yield potential, a dynamic model for winter beet was used to compare growth and yield of conventional, spring sown sugar beet (CB) with two non-bolting winter beet types at five representative sites across Germany. Non-bolting winter beets...
Yield development of agricultural crops over time is not merely the result of genetic and agronomic factors, but also the outcome of a complex interaction between climatic and site‐specific soil conditions. However, the influence of past climatic changes on yield trends remains unclear, particularly under consideration of different soil conditions....
![Mean absolute errors (MAE [m² m⁻²]) and relative Mean absolute errors...](publication/339270677/figure/fig3/AS:11431281255164317@1719405920699/Mean-absolute-errors-MAE-m-m-and-relative-Mean-absolute-errors-rMAE-of-the_Q320.jpg)
Introduction
In recent decades, the interest has grown to quantify the green area index as one of the key characteristics of crop canopies (e.g. for modelling transpiration, light interception, growth). The approach of estimating green area index based on multispectral reflection data from unmanned airborne vehicles with lightweight sensors might h...
A new dynamic crop growth model based on empirically derived allometric partitioning rules was developed for winter oilseed rape. The model simulates dry matter production, nitrogen uptake and distribution, leaf, stem and pod area expansion and yield formation under optimal and water- and nitrogen-limited conditions.
The model includes hibernation,...
Wheat yields in many of the main producing European countries stagnate since about 20 years. Hence, it is of high interest, to analyze breeding progress in terms of yield and how associated traits changed. Therefore, a set of 42 cultivars (released between 1966 and 2012) was selected and yield as well as functional traits defined by the Monteith an...
The world cropping area for wheat exceeds that of any other crop, and high grain yields in intensive wheat cropping systems are essential for global food security. Breeding has raised yields dramatically in high-input production systems; however, selection under optimal growth conditions is widely believed to diminish the adaptive capacity of culti...
Autumn-sown sugar beets may achieve a faster canopy closure in spring compared to spring-sown sugar beets, thus increasing radiation interception and yield. However, to date yield benefits of autumn-sown beets cannot be quantified, as they start to bolt in spring. Therefore, simulation models for winter beet need to be developed.
From 2009 to 2012,...
Increasing CO2 concentration ([CO2]) is thought to induce climate change and thereby increase air temperatures and the risk of drought stress, the latter impairing crop growth. The objective of this study was to investigate the effects of elevated [CO2] and drought stress on root growth of one maize genotype (Zea mays cv. Simao) and two sorghum gen...
Silage maize (Zea mays L.) is the dominating energy crop for biogas production due to its high biomass yield potential, but alternatives are currently being discussed to avoid environmental problems arising from maize grown continuously. This study evaluates the productivity and resource use efficiency of different bioenergy crops and cropping syst...
Phenological development can be seen as the biological clock of crops and crop model developers used this timeline for describing various processes associated with leaf area dynamics. The critical shoot nitrogen concentration (cNcrit; a reference to quantify crop nitrogen status), leaf-stem partitioning and specific leaf area (SLA) are often simula...
The SMN dynamics suggest nitrogen immobilization after treatments with substrates with a low C-N-ratio. Though, this does not explain the reduction of the calculated maximum wheat yield in the WW straw treatment. Pathogen transfer by wheat residues may be an explanation that need further investigation. Also, a non-compensable N deficiency in the ea...
Despite widespread application in studying climate change impacts, most crop models ignore complex interactions among air temperature, crop and soil water status, CO2 concentration and atmospheric conditions that influence crop canopy temperature. The current study extended previous studies by evaluating Tc simulations from nine crop models at six...
A 41-day incubation trial was conducted to test the single and combined effects of the novel urease (N-(2-Nitrophenyl) phosphoric triamide, 2-NPT) and nitrification inhibitors (mixture of dicyandiamide and 1H-1,2,4-triazole, DCD/TZ) on N2O emissions and underlying soil processes from a North German sandy loam soil. The effects of treatment on N2O e...
Winter oilseed rape (Brassica napus L., WOSR) is the major oil crop cultivated in Europe. Rapeseed oil is predominantly used for production of biodiesel. The framework of the European Renewable Energy Directive requires that use of biofuels achieves GHG savings of at least 50% compared to use of fossil fuel starting in 2018. However, N2O field emis...
Surface application of cattle slurry on grassland is characterized by a high risk of ammonia (NH3) losses. Different techniques and measures to lower these emissions are available, but reported abatement efficiencies vary substantially among studies. Therefore, a direct comparison of five different slurry application techniques was conducted in a t...
For biomethane production, the cup plant (Silphium perfoliatum L.) is considered a promising alternative substrate to silage maize (Zea mays L.) due to its high biomass potential and associated ecological and environmental benefits. It has also been suggested to grow cup plant on less productive soils because of its presumed drought tolerance, but...
Improvement of grain yield potential for winter wheat (Triticum aestivum) may become harder to achieve in the future because an increase of harvest index has been largely exploited by breeders. Therefore, it is of high interest to detect how the components of the yield equation GY = Q × LUE × HI (GY: grain yield, Q: radiation interception, LUE: lig...
Field experiments show that wheat grown after oilseed rape (OSR) achieves higher yield levels, while the nitrogen (N) application is reduced. However, field experiment data are based on few locations with optimised management. We analysed a large dataset based on farm data to assess the true extent of break crop benefits (BCB) for yield and N ferti...
Winter oilseed rape (WOSR) is a major crop in Germany, combining economic benefits with a high value in crop rotation, but it still lacks agronomically sound concepts for site-specific nitrogen (N) fertilization. Since ecological challenges resulting from high optimal N rates and a low N harvest index are approaching on WOSR cropping systems, optim...
In northern Europe, replacing winter barley with winter wheat as the preceding crop for winter oilseed rape (Brassica napus L.; WOSR) often results in a delayed WOSR sowing and poor autumn growth. Based on data from a field experiment running in 2009/2010, 2010/2011, and 2012/2013, this study aims (i) to investigate how a delayed sowing method affe...
In many parts of Europe, farmers often replace winter barley by winter wheat as preceding crop for winter oilseed rape (WOSR) resulting in a delayed WOSR sowing and poor autumn growth. Based on data from a field trial running in 2009/10, 2010/1l, and 2012/13, this study aims i) to investigate how a delayed sowing impairs autumnal above-ground and t...
The cup plant (Silphium perfoliatum L.) is presently discussed as a promising alternative to silage maize for biomethane production in Germany. It is assumed that the cup plant develops a profound root system, contributing decisively to the drought tolerance of this crop. This study is aimed at providing the first experimental data on root growth a...
Carbon and nitrogen partitioning of winter oilseed rape differs under optimal and nitrogen (N) limited conditions. The quantitative description of these processes and their response to N deficiency is a prerequisite to develop process-oriented crop growth models capable to predict responses to a limited N supply. Dry matter (DM) partitioning, N dyn...
We investigated the leaf: stem partitioning of winter wheat (Triticum aestivum L. varieties 'Dekan' and 'Batis') with and without drought influence. Irrigated and drought-stressed winter wheat, grown in a rainout shelter in 2009/10 and 2013/14, were sampled during shoot elongation phase at the experimental Farm Hohenschulen located in Northern Germ...
The fraction of dry matter and nitrogen (N) allocated to leaves is of high importance for wheat crop simulators, because it has an impact on N demand, evapotranspiration, light interception and light use efficiency. For the vegetative phase of wheat, a robust empiric description of the influence of N nutrition status (NNI) on this pattern is still...
Description of experimental approach of manipulating topsoil C/N-ratio on arable land in order to activate microbial immobilization of N in intercropping season
The spatial variability of yields and optimal N rates is well documented for several crops and the benefit of studying site-specific N response seems self-evident. Unfortunately, trials established to examine site-specific N response are mostly quite large and expensive, since those trials usually cover nearly the whole field. Selecting only small...
Implementation of the BBCH coding system for winter oilseed rape (OSR) phenology simulation can allow detailed description of crop ontogeny necessary for crop management and crop growth modelling. We developed such a BBCH model using an existing approach (Habekotté 1997).
The new model describes winter OSR development by a combination of differenti...
The cup plant (Silphium perfoliatum L.) is discussed as an alternative energy crop for biogas production in Germany due to its ecological benefits over continuously grown maize. Moreover, a certain drought tolerance is assumed because of its intensive root growth and the dew water collection by the leaf cups, formed by fused leaf pairs. Therefore,...
The prediction of the allocation of carbon and nitrogen into the different organs, e.g., leaves, stems, roots of a growing plant is a pivotal part of mechanistic growth models. Based on 2 year (winter wheat) and 3 year (winter barley) field trials with different N treatments (0-240kgNha-1), the objectives of this study were to verify currently used...
Crop system models are generally parametrized with daily air temperatures recorded at 1.5 or 2 m height. These data are not able to represent temperatures at the canopy level, which control crop growth, and the impact of heat stress on crop yield, which are modified by canopy characteristics and plant physiological processes Since such data are oft...
Information on growth of rye (Secale cereale L.) and triticale (X Triticosecale Wittmark) are scarce. In 2007/08 and 2008/09, winter rye, winter triticale and winter wheat (Triticum aestivum L.) were simultaneously grown in combination with 4 nitrogen (N) treatments (0/0, 40/40, 80/80 and 120/120 kg N ha⁻¹) at the Hohenschulen Experimental Farm in...
The canopy temperature is an important variable for predicting the impact of heat stress on grain yield. However, established agroecosystem models often use strongly simplified approaches, e.g., based on the air temperature, to estimate the response of canopy/canopy-within temperature to ambient conditions. Consequently, large model uncertainties a...
Among the parameters of global climate change the increases of the atmospheric CO2 concentration and of temperature, both of which affect plant growth and development, are of prime importance. However, with respect to the importance of these climate changes for global food security little is known on the possible interactions of these prominent cha...
Three different explanatory indicators for reduced light use efficiency (LUE) under limited nitrogen (N) supply were evaluated. The indicators can be used to adapt dry matter production of crop simulators to N-limited growth conditions. The first indicator, nitrogen factor (NFAC), originates from the CERES-Wheat model and calculates the critical N...
An accurate estimation of stomatal resistance (rS) also under drought stress conditions is of pivotal importance for any process-based prediction of transpiration and the energy budget of real crop canopies and quantification of drought stress. A new model for rS was developed and parameterized for winter wheat using data from field experiments acc...
The design of site-adapted biogas cropping systems that combine high methane yield and low environmental impact represents a major challenge for biogas production. A 2-year field experiment was conducted at Hohenschulen, northern Germany, to quantify the nitrate leaching potential and the ecological efficiency, in terms of nitrate-N load per megali...
Winter oilseed rape (WOSR) is an important oil and protein crop in Europe, used in biofuel production and as protein source in livestock farming. In contrast to cereals, WOSR seed yields are still increasing in most countries but yield stability was not improved during the last decades.In our study, we analyzed the effects of weather conditions dur...
In most regions, sugar beet is normally sown as a spring crop. If sown in autumn the crop remains on the field over winter and may achieve fast re-growth in spring from assimilates stored within the beet, allowing earlier leaf growth and light interception in spring. The specific leaf area (SLA) (ratio between leaf surface and leaf mass) is mainly...
There is a growing concern that greenhouse gas (GHG) emissions during agricultural energy crop production might negate GHG emission savings which was not intended when promoting the use of renewable energy. Nitrous oxide (N2O) is a major GHG, and in addition, it is the most powerful ozone-depleting compound that is emitted by human activity. The us...
Crops generally utilize nitrogen (N) from slurries less efficiently than from mineral fertilizers. In order to compare the effects of slurry and mineral N application on yield and residual fertilization effects, a long-term field trial was established in autumn 1994, where pig slurry was applied to oilseed rape (OSR), winter wheat and winter barley...
With its policy paper the Senate Commission on Agro-ecosystem Research of the Deutsche Forschungsgemeinschaft (DFG) summarizes potential benefits of basic research for the sustainable intensification of crop production. Agro-ecosystems critically contribute to fulfilling the need for increasing food and fiber production, diminishing resource deplet...
Eliminating uncertainty in soil N supply could reduce fertilizer input, but the amount of N mineralized during plant growth is usually still unknown. We aimed to test the relatively simple two-pool net N mineralization model NET N that uses site-specific temperature and soil water functions as well as pedotransfer functions for deriving the pool si...
In organic potato (Solanum tuberosum) production in Europe, solely copper-based fungicides allow to directly control late blight (caused by Phytophthora infestans). Due to environmental concerns, the use of copper (Cu) fungicides has to be as efficiently as possible to reduce annual consumption. This can be achieved either by reducing the dose per...
Increasing crop productivity while simultaneously reducing the environmental footprint of crop production is considered a major challenge for the coming decades. Even short episodes of heat stress can reduce crop yield considerably causing low resource use efficiency. Studies on the impact of heat stress on crop yields over larger regions generally...
Anaerobic digestates (AD) from biogas production are applied to agricultural land as organic fertilizers, but pose an ammonia (NH3) emission source. However, data about NH3 emissions of cold season AD land spreading is still lacking. Therefore, in the present study NH3 emissions of AD application under winter conditions were determined. AD was appl...
We analyzed under the temperate weather conditions of northwest Germany the relationships between soil water supply, crop canopy dynamics, radiation interception, components of the soil water balance and grain yield of winter wheat using data obtained from field experiments during three years. A dynamic model of the soil water budget in combination...
A considerable expansion of biogas production in Germany, paralleled by a strong increase in maize acreage, has caused growing concern that greenhouse gas (GHG) emissions during crop substrate production might counteract the GHG emission saving potential. Based on a 2-year field trial, a GHG balance was conducted to evaluate the mitigation potentia...
In crop growth simulators, the daily increase of leaf area is often derived from the product of leaf mass increase and specific leaf area (SLA), while the SLA of already formed and expanded leaves is assumed as conserved. The SLA is influenced by many factors and remarkable efforts have been made to isolate the most important ones, aiming to obtain...
