Kristian Thorup-Kristensen

• PhD
• Professor (Full) at University of Copenhagen

Background and aims Root systems show considerable plasticity in their morphology and physiology in response to variability within their environment. Root elongation below a water-table was expected to slow due to hypoxia, whilst roots above the waterlogged zone were expected to compensate by increasing elongation rates. Methods Tomato plants (Sol...

One of the core ideas behind organic production is that cropping systems should be less dependent on import of resources, and minimize negative effects on the surrounding environment compared to conventional production. However, even when clearly complying with regulations for organic production, it is not always obvious that these goals are reache...

Unused inorganic nitrogen (Ninorg) left in agricultural soils will typically leach to deeper soil layers. If it moves below the root zone it will be lost from the system, but the depth of the root zone depends on the crop species grown. In this experiment we studied the effect of 3-year crop sequences, with different combinations of deep-rooted and...

We present a 2-D model for simulation of root density and plant nitrogen (N) uptake for crops grown in agricultural systems, based on a modification of the root density equation originally proposed by Gerwitz and Page in J Appl Ecol 11:773–781, (1974). A root system form parameter was introduced to describe the distribution of root length verticall...

Breeding for potato deep roots can increase water and nitrogen uptake by potatoes and it can be an option to maintain stable yields with decreased inputs. This study investigates the relationship between potato root characteristics, water stress resistance and deep soil nitrogen uptake, accessing variations among cultivars and nitrogen fertilizatio...

Background and aims Defoliation triggers the remobilisation of root reserves to generate new leaves which can affect root growth until the shoot resumes net assimilation. However, the duration of root growth cessation and its impact on resource uptake potential is uncertain. Methods Winter wheat was established in a 4 m high outdoor rhizobox facil...

Background In drought periods, water use efficiency depends on the capacity of roots to extract water from deep soil. A semi-field phenotyping facility (RadiMax) was used to investigate above-ground and root traits in spring barley when grown under a water availability gradient. Above-ground traits included grain yield, grain protein concentration,...

Background In drought periods, water use efficiency depends on the capacity of roots to extract water from deep soil. A semi-field phenotyping facility (RadiMax) was used to investigate above-ground and root traits in spring barley when grown under a water availability gradient. Above-ground traits included grain yield, grain protein concentration,...

Background and aims Root distribution over the soil profile is important for crop resource uptake. Using machine learning (ML), this study investigated whether measured square root of planar root length density (Sqrt_pRLD) at different soil depths were related to uptake of isotope tracer (15N) and drought stress indicator (13C) in wheat, to reveal...

Background and aims Deep roots are needed to allow uptake of nitrogen (N) and water available in the deeper soil layers, to help tolerate increasingly extreme climates. Yet few studies in the field have been able to identify genetic differences in deep roots and how this relates to N and water uptake. This study aimed to identify the relationship b...

Crops with deeper rooting is an emerging tool for better exploitation of soil resources. However, there is a need for more in-depth understanding on how the increased rooting depth may be achieved. In this study a novel approach for obtaining deeper rooting has been proposed. Crops with assumed similar capacity for subsoil exploration: sugar beet (...

Background and Aims Deep roots are needed to allow uptake of N and water available in the deeper soil layers, to help tolerate increasingly extreme climates. Yet few studies in the field have been able to identify genetic differences in deep roots and how this relates to N and water uptake. This study aimed to identify the relationship between deep...

Background and aims Root distribution over the soil profile is important for crop resource uptake. Using machine learning (ML), this study investigated whether measured planar root length density (pRLD) at different soil depths were related to uptake of isotope tracer (15N) and drought stress indicator (13C) in wheat, to reveal root function. Meth...

Soil biopore genesis is a dynamic and context-dependent process. Yet integrative investigations of biopore genesis under varying soil type, tillage and vegetation history are rare. Recent advances in Machine Learning (ML) made faster and more accurate image analysis possible. We validated a model trained on Convolutional Neural Network (CNN) using...

Little is known how the deep root systems of perennial crops contribute to deeper and better resource use when intercropped with annuals in arable fields. Therefore, we aimed at measuring the capacity of deep-rooted perennials, alfalfa (Medicago sativa L.) and curly dock (Rumex crispus L.) to access nutrients located under neighboring annuals at 1....

Conservation agriculture (CA) has been reported to affect nutrient cycling. This study aims to investigate how CA induced soil organic matter stratification affects carbon and nitrogen turnover. A case farm study was established on two Danish farms with conventional ploughed tillage (P) and CA practises. Here, we studied how organic matter stratifi...

Whole-genome multi-omics profiles contain valuable information for the characterization and prediction of complex traits in plants. In this study, we evaluate multi-omics models to predict four complex traits in barley (Hordeum vulgare); grain yield, thousand kernel weight, protein content, and nitrogen uptake. Genomic, transcriptomic, and DNA meth...

The growing demand for food and feed crops in the world because of growing population and more extreme weather events requires high‐yielding and resilient crops. Many agriculturally important traits are polygenic, controlled by multiple regulatory layers, and with a strong interaction with the environment. In this study, 120 F2 families of perennia...

Convolutional neural networks (CNNs) are a powerful tool for plant image analysis, but challenges remain in making them more accessible to researchers without a machine‐learning background. We present RootPainter, an open‐source graphical user interface based software tool for the rapid training of deep neural networks for use in biological image a...

Enhanced nitrogen (N) and water uptake from deep soil layers may increase resource use efficiency while maintaining yield under stressed conditions. Winter oilseed rape (Brassica napus L.) can develop deep roots and access deep-stored resources such as N and water to sustain its growth and productivity. Less is known of the performance of deep root...

Background and Aims Deep roots (i.e., > 1 m depth) are important for crops to access water when the topsoil is dry. Root anatomy and hydraulic conductance play important roles in the uptake of soil water, particularly water located deep in the soil. We investigated whether root and xylem anatomy vary as a function of root type, order and length or...

Comprehensive climate change mitigation necessitates soil carbon (C) storage in cultivated terrestrial ecosystems. Deep-rooted perennial crops may help to turn agricultural soils into efficient C sinks, especially in deeper soil layers. Here, we compared C allocation and potential stabilization to 150 cm depth from two functionally distinct deep-ro...

PurposeLittle is known about phosphorus (P) uptake at deep soil layers, e.g. below 1 m of soil depth. We aimed at tracing P uptake up to 4.2 m of soil depth of different plant species in an arable field using 33P isotope combined with the core-labelling technique.Methods Soil was packed into ingrowth-cores and labelled with H3 33PO4. The ingrowth c...

Aims Perennial crops with more extensive and deep root systems could access deep stored water and build resilience to water shortage. In the context of human nutrition, perennial grain crops are very interesting. However, it is still questionable whether they are effective in using subsoil water. We compared intermediate wheatgrass (Kernza®) Thinop...

Weed control is important to improve crop yield in organic farming. In Northern Europe, the use of mechanical weed control restricts the ability to use green manure-cover crops that could be a key source of N supply. In a two-year experiment repeated twice, the objective of this study was to compare the effect of cover crop- and autumn tillage-base...

Predicting N mineralization from green manure in different soil types during the cold season is instrumental for improving crop management with higher N use efficiency and reduced risks of N losses in a cool and humid climate. The objective of our work was to study the effects of low temperatures and soil type on the net nitrogen (N) mineralization...

Little is known of how the deep root systems of perennial crops contribute to deeper and better resource use when intercropped with annuals in arable fields. Therefore, we aimed at measuring the capacity of perennial deep roots, alfalfa ( Medicago sativa L.) and curly dock ( Rumex crispus L.) to access the nutrient source located under the neighbor...

Introduction Agricultural intensification results in biodiversity loss through land conversion and management practices which negatively impact arthropods. The abundance and diversity of ground-dwelling predators, e.g. ground beetles (Coleoptera: Carabidae) and spiders (Araneae), are negatively affected by soil disturbances such as tillage. Reducin...

The objective of this study was to evaluate the usage of species with coloured roots to study root growth patterns during intercropping. Red beet (Beta vulgaris L. cv. Detroit), having clear red roots, was used in a semi-field and field experiment to allow identification and quantification of roots of the individual species in the mixture. In the f...

Deep rooting winter wheat genotypes can reduce nitrate leaching losses and increase N uptake. We aimed to investigate which deep root traits are correlated to deep N uptake and to estimate genetic variation in root traits and deep ¹⁵N tracer uptake. In two years, winter wheat genotypes were grown in RadiMax, a semi-field root-screening facility. Mi...

Aims Enhanced nitrogen (N) and water uptake from deep soil layers may increase resource use efficiency whilst maintaining yield under stressed conditions. Winter oilseed rape ( Brassica napus L.) can develop deep roots and access deep-stored resources such as N and water, while this potential has large uncertainties in variable environments. In thi...

AimsWater is the most important yield-limiting factor worldwide and drought is predicted to increase in the future. Perennial crops with more extensive and deep root systems could access deep stored water and build resilience to water shortage. In the context of human nutrition, perennial grain crops are very interesting. However, it is still quest...

Mechanistic models are useful tools for understanding and taking account of the complex, dynamic processes such as carbon (C) and nitrogen (N) turnover in soil and crop growth. In this study, the EU-Rotate_N model was first calibrated with measured C and N mineralization from nine potential fertilizer resources decomposing at controlled soil temper...

Ecological intensification is crucial for arable organic farmers, in order to partly close the yield gap to conventional yields. One strategy for this is improved management of cover crops, to increase availability of both nitrogen (N), phosphorus (P) and sulfur (S) for the subsequent main crop. However, the potential of cover crops to take up and...

Purpose Precrops exhibit vigorous deep root growth, especially when grown perennially. However, their contribution to accumulate essential nutrients derived from deeper soil layers in the topsoil has not been quantified. We determined the vertical distribution of phosphorous (P) and potassium (K) affected by contrasting root systems of 3 precrops a...

Aims Deep-rooted crops have been widely used in agricultural systems to access deep resources such as water and nitrogen (N). However, the potential of deep roots to take water and N at various depths have not been well studied. Here we used chicory (Cichorium intybus L.) to study the potential and dynamics of water and nitrogen uptake in deep soil...

The scale of root quantification in research is often limited by the time required for sampling, measurement and processing samples. Recent developments in Convolutional Neural Networks (CNN) have made faster and more accurate plant image analysis possible which may significantly reduce the time required for root measurement, but challenges remain...

The scale of root quantification in research is often limited by the time required for sampling, measurement and processing samples. Recent developments in Convolutional Neural Networks (CNN) have made faster and more accurate plant image analysis possible which may significantly reduce the time required for root measurement, but challenges remain...

Patterns and level of cytosine methylation vary widely among plant species and are associated with genome size as well as the proportion of transposons and other repetitive elements in the genome. We explored epigenetic patterns and diversity in a representative proportion of the spring barley (Hordeum vulgare L.) genome across several commercial a...

This is how it looks when the ingrowth-cores are retracted after the 8 weeks of incubation time in deep soil layers. Alfalfa roots successfully grew into the ingrowth-cores at 1.0, 2.5 and 4.2 m of soil depths. The soil inside was labelled with 5 different nutrient tracers- which we detected in aboveground biomass. This was how we validated our cor...

Background: Deeper roots help plants take up available resources in deep soil ensuring better growth and higher yields under conditions of drought. A large-scale semi-field root phenotyping facility was developed to allow a water availability gradient and detect potential interaction of genotype by water availability gradient. Genotyped winter whe...

Background: Ingrowth-core method is a useful tool to determine fine root growth of standing crops by inserting root-free soil in mesh-bags for certain period of time. However, the root density observed by the method does not directly explain the nutrient uptake potential of crop plants as it varies over soil depth and incubation time. We have inser...

We present RootPainter, a GUI-based software tool for the rapid training of deep neural networks for use in biological image analysis. RootPainter facilitates both fully-automatic and semi-automatic image segmentation. We investigate the effectiveness of RootPainter using three plant image datasets, evaluating its potential for root length extracti...

Background Deeper roots can help plants to take up available resources in deep soil ensuring better growth and higher yields under conditions of limited water supply. The objective was to explore the possibility of genomic prediction for grain-related and root traits of winter wheat measured in a semi-field root phenotyping facility allowing for a...

In the quest for sustainable intensification of crop production, we discuss the option of extending the root depth of crops to increase the volume of soil exploited by their root systems. We discuss the evidence that deeper rooting can be obtained by appropriate choice of crop species, by plant breeding, or crop management and its potential contrib...

Aims Deep-rooted agricultural crops can potentially utilize deep soil moisture to reduce periods where growth is water limited. Chicory (Cichorium intybus L.) is a deep-rooted species, but the benefits of deep roots to water uptake has not been studied. The aim of this study was to investigate the value of deep roots (>2 m) under topsoil water limi...

AimsWe tested if chicory acquires nutrients from soil layers down to 3.5 m depth and whether the deep nutrient uptake increases as a result of drought or intercropping with ryegrass and black medic. We also tested whether application of the trace elements Cs, Li, Rb, Sr and Se, as tracers, result in similar uptake rates.Methods The methodological t...

Background: Deep rooting is one of the most promising plant traits for improving crop yield under water-limited conditions. Most root phenotyping methods are designed for laboratory-grown plants, typically measuring very young plants not grown in soil and not allowing full development of the root system. Results: This study introduced the 15N tr...

This study was performed to i) compare root distribution of legume/non-legume intercrops determined by qPCR and amplicon sequencing (Meta-barcoding) to root growth of the individual species determined visually, and ii) compare the qPCR and amplicon sequencing techniques as a method for quantifying root growth of individual species grown in mixtures...

Aims Roots are vital organs for plants, but the assessment of root traits is difficult, particularly in deep soil layers under natural field conditions. A popular technique to investigate root growth under field or semi-field conditions is the use of minirhizotrons. However, the subsequent manual quantification process is time-consuming and prone t...

Perennial ryegrass (Lolium perenne L.) is the predominant forage grass in temperate climates, due to its high forage quality. Drought is a growth-limiting factor for such temperate grasses, which have to survive and recover after a period of prolonged drought. The aims of our study were to analyse whole genome RNAseq data in the context of differen...

Background and Aims The line intersect method is widely used in rhizotron and minirhizotron studies to quantify roots and study cultivar and treatment differences in root growth. We investigated ways to optimize the line intersect method and root depth measurements with respect to data variability and the time spent on counting roots. Methods Root...

Background Roots are vital organs for plants, and the effective use of resources from the soil is important for yield stability. However, phenotypic variation in root traits among crop genotypes is mostly unknown and field screening of root development is costly and labour demanding. As a consequence, new methods are needed to investigate root trai...

Aims: We tested if chicory acquires nutrients from soil layers down to 3.5 m depth and whether the deep nutrient uptake increases as a result of topsoil drought or topsoil resource competition. We also tested whether application of the trace elements Cs, Li, Rb, Sr, and Se, as tracers result in similar uptake rates. Methods: The methodological test...

Aims Deep-rooted agricultural crops can potentially utilize deep water pools and thus reduce periods where growth is water limited. Chicory ( Cichorium intybus L.) is known to be deep-rooted, but the contribution of deep roots to water uptake under well-watered and drought conditions by the deep root system has not been studied. The aim of this stu...

Selection for deep rooting is critical for the development of genotypes that are able to explore deep soil water and nutrients, particularly as agricultural resources become more limited. However, current root phenotyping techniques demand significant investments of time, money, and effort, and measurements on very young plants or plants grown unde...

Application of green manures is an effective approach to optimizing N management in paddy soils. Nitrification is a key process in the N cycle and ammonia oxidization is the first and typically limiting step in nitrification. In this study, we investigated the changes of ammonium oxidizing prokaryotes after the application of green manure in a red...

Aims There is much evidence that plant competition below ground is size symmetric, i.e. that competing plants share contested resources in proportion to their sizes. Several researchers have hypothesized that a patchy distribution of soil nutrients could result in size-asymmetric root competition. We tested this hypothesis. Methods In a greenhouse...

Plants in living walls face challenges from intraspecific and interspecific competition from plants around them, as well as water and nutrient availability in the growing media. This paper explores these challenges using four different species of hardy perennials. Campanula poscharskyana ‘Stella’, Geranium sanguineum ‘Max Frei’, Sesleria heuflerian...

Fast and accurate methods for determining root growth in situ are important tools. In the present study, a rhizotron tube method was trialed as a means to more conveniently observe the dynamic development of roots under conditions similar to those encountered in the field. Crops were planted in transparent tubes covered with photomask to ensure a d...

Background and aims A study was made to quantify early root development, soil exploitation and nutrient uptake in spring wheat, onion and lettuce, and their variation among cultivars. The goal was to study genetic variation in root traits making cultivars better adapted to organic production systems or other low-input systems. Methods Six cultivars...

Determining genotypic responses to soil fertility may assist selection of cultivars that can be adapted to varied soil fertility regimes, and such selection under field conditions is still limited. A two-year field experiment was conducted in long-term field trials to investigate wheat genotype effects on early growth, yield and nutrient accumulati...

Background There has been renewed global interest in both genetic and management strategies to improve root system function in order to improve agricultural productivity and minimize environmental damage. Improving root system capture of water and nutrients is an obvious strategy, yet few studies consider the important interactions between the gene...

Nitrate leaching from agricultural land is a major environmental concern. Earlier sowing of winter wheat (Triticum aestivum L.) could be a tool to reduce nitrate leaching loss, as deeper root penetration and increased biomass production might increase the N uptake during autumn. Quantitative estimates of the effect of sowing time are needed. A two-...

Abstracts: 72-73. http://akkonferens.slu.se/nitrogenworkshop/

A number of root and root hair traits have been proposed as important for nutrient acquisition. However, there is still a need for knowledge on which traits are most important in determining macro- and micronutrient uptake at low soil fertility. This study investigated the variations in root growth vigor and root hair length (RHL) and density (RHD)...

Translational science deals with the dilemma between basic research and the practical application of scientific results. In translational plant science, focus is on the relationship between agricultural crop production and basic science in various research fields, but primarily in the basic plant science. Scientific and technological developments h...

Winter oilseed rape (Brassica napus L.) has a high capacity for nitrogen (N) uptake, but still leaves substantial amounts of N in the soil after harvest, partly due to the N lost through shed leaves. Reduced leaf litter losses or increased N uptake might therefore be possible ways of increasing the N efficiency of winter oilseed rape. In order to d...

On the basis of a long-term (30 years) field experiment that involved four rotation systems, rice-rice-winter fallow (RRF), rice-rice-ryegrass (RRG), rice-rice-rape (RRP), and rice-rice-milk vetch (RRV), this study described the effects of green manure on the microbial communities in the red paddy soils using 454 pyrosequencing for the 16S rRNA gen...

A five-year field study was conducted in order to identify and test plant species suitable as undersown nitrogen (N) catch crops. With the aim of maximizing the catch crop effect against N leaching loss, the main focus was on identifying species with deeper rooting than ryegrass (Lolium perenne L.), which is typically used for this purpose. More th...

One way to reduce nitrate leaching losses from agricultural land is to increase crop nitrogen uptake efficiency (NUpE). In this aspect, root growth is an essential parameter, as more and deeper roots may improve the uptake from deeper soil layers and reduce nitrate leaching.

Aims Intercropping legumes and non-legumes may affect the root growth of both components in the mixture, and the non-legume is known to be strongly favored by increasing nitrogen (N) supply. The knowledge of how root systems affect the growth of the individual species is useful for understanding the interactions in intercrops as well as for plannin...

Winter Orychophragmus violaceus (OV)/spring maize is a novel eco-agricultural system in North China Plain, but little is known about OV’s nitrogen (N) effects on succeeding maize growth and its contribution to maize N uptake and utilization during the growth. A pot experiment using 15N was conducted, including five treatments: (1) Control – without...

The entomopathogenic fungal Metarhizium anisopliae lineage harbors cryptic diversity and was recently split into several species. Metarhizium spp. are frequently isolated from soil environments, but the abundance and distribution of the separate species in local communities is still largely unknown. Entomopathogenic isolates of Metarhizium spp. wer...

The study aimed to evaluate the extent to which Metarhizium spp. applied as conidia to seeds will disperse with the growing root system and maintain pathogenicity after dispersion. Tenebrio molitor larvae were exposed to roots of wheat plants that had been grown from seeds inoculated with conidia of either M. brunneum (KVL 04-57 and KVL 12-37) or M...

Deeper plant root systems are desired for improved water and nitrogen uptake in leaching environments. However, phenotyping for deep roots requires methods that enable plants to develop deep roots under realistic conditions. Winter cereals raise further complications as early growth occurs under low light and temperature during autumn and winter—co...