Hanne. Lakkenborg Kristensen

Aarhus University | AU · Department of Food Science

Background and aimsWe investigated whether the incorporation of intercropped white clover as a split-dose fertiliser improves N retention of the plant-soil system in leek production. Methods White clover and leek were grown in pots where clover was stepwise incorporated into soil as fertiliser. Half of the clover was incorporated before leek transp...

Organic vegetable production has a demand for alternative fertilizers to replace fertilizers from sources that are not organic, that is, typically animal‐based ones from conventional farming. The aim of this study was to develop production strategies of plant‐based fertilizers to maximize cumulative nitrogen (N) production (equal to N yield by gree...

Sustainably increasing organic vegetable crop productivity is needed to meet growing demands, considering replacement of conventional animal manures with alternative fertilizers. We investigated the effects of intercropping (IC) and different organic fertilization strategies, and their interactions, on the plant-soil system. A 2-year IC field exper...

Crop diversification in spatial and temporal patterns can optimize the synchronization of nutrients plant demand and availability in soils, as plant diversity and soil microbial communities are the main drivers of biogeochemical C and nutrient cycling. The introduction of multi-cropping in organic vegetable production can represent a key strategy t...

A sustainably intensified (SI) organic vegetable rotation, employing plant-based fertilizers, more crops, reduced tillage, and cover crops was compared to common practice (CP) where plants were fertilized with animal manure, typically one crop was grown per season, soil was plowed and often left bare over winter. Second and third-year results are p...

Although organic farming was originally promoted as an alternative farming system to address agronomic, environmental and ecological issues, its conventionalisation has led to an intensification and specialisation of production. In the light of this, several studies have questioned the environmental benefits of organic farming as well as its agrono...

Intercropping can improve yield and nitrogen use efficiency in organic vegetable production by pairing crops with complementary resource use. An intercrop field experiment was conducted to determine yield, root growth and nitrogen (N) dynamics using faba bean (Vicia faba L.) grown as a vegetable and pointed cabbage (Brassica oleracea var. capitata...

Aims Plant available soil nitrogen (N) may affect deep root growth and soil N depletion by catch crops. We investigated the influence of topsoil N availability on root growth and uptake by fodder radish. Methods We conducted field and greenhouse experiments of root growth and late autumn N uptake at medium and high soil N availabilities, and root...

Lime and phosphorus (P) applications are common agricultural management practices. Our aim was to quantify the effects of long‐term application practices on root growth and abundance of arbuscular mycorrhizal fungi (AMF) under field conditions. We assessed the effects of lime and P fertilizer applications on barley yield, root growth and AMF abunda...

Growing nitrogen (N)-fixing green manure, such as red clover (Trifolium pratense L.), in blackcurrant (Ribes nigrum L.) plantation alleys for use as a plant-based fertiliser could potentially reduce the need for animal manure fertilisation in organic farming. Knowledge about nutrient release from plant-based fertilisers is limited. Therefore, a bla...

Vegetables rich in bitter-tasting phytochemicals may exert enhanced beneficial effects against key factors associated with type two diabetes (T2D). This study investigates whether selected cultivars of bitter and strong-tasting (BST) Brassica and root vegetables exert greater health benefits on T2D patients compared to equivalent modern mild and sw...

Subsoil compaction in arable farming caused by increasingly heavy machinery results in increased subsoil strength and reduced aeration and water flow. This can restrict root growth and reduce crop yield. To mitigate these effects of subsoil compaction, we included a deep-rooted catch crop of fodder radish (Raphanus sativus var. oleifera) in a rotat...

N fertilization is often viewed as a cheap insurance against yield loss in vegetable production because of the generally large added value, resulting in application of fertilizer N often in excess of actual crop demand. In combination with the low fertilizer N recovery by many vegetable crops and the often excessive irrigation, this may lead to bot...

Agro-ecological service crops (ASCs), also known as cover crops, green manures or catch crops, can improve organic vegetable production in terms of weed suppression, nitrogen (N) recycling, or addition of N through symbiotic N2 fixation by legumes. Traditionally, ASCs are terminated through full incorporation into the soil (FI), but alternative ter...

Introduction Benzoxazinoids (BXs) are plant phytochemicals that have both defensive properties in plants and therapeutic effects in humans. The presence of BXs has been largely studied in the Poaceae family (monocots). To study the presence or absence of BXs in dicotyledons and monocotyledons outside the Poaceae family, parts of 24 plant species at...

Roller-crimping of cover crops grown during winter may facilitate reduced tillage efforts in organic vegetable production. A one-year field experiment was conducted twice (autumn 2015–2017) in sandy loam soil in Denmark testing two cover crop termination systems, roller-crimping (RC) without tillage before crop planting, and full incorporation by t...

Agroecological service crops are introduced into the vegetable crop rotation to provide agroecosystem services, and are a key strategy for weed management in organic systems. Organic farmers across Europe usually terminate these crops before cultivation of the subsequent cash crop, using them as green manure. Recently, the in-line tillage-roller cr...

The chemical and sensory quality of field‐grown vegetables may be influenced by cultivar choice and agronomic factors but knowledge is lacking on the new rapeseed vegetables. White‐ and yellow‐flowering rapeseed cultivars were tested in two seasonally different field studies in Denmark at three different growing stages by early sowing the first yea...

Increased farm machinery weight in agricultural production results in soil compaction. Controlled traffic farming (CTF) restricts traffic to permanent lanes, thereby creating traffic free beds for crop production. Field experiments were conducted at two organic vegetable farms in Denmark, on a sandy loam (2013-2016) and on coarse sand (2013-2015) t...

Climatic data from the two growing seasons, 2016 and 2017. Daily average temperature (°C), daily precipitation (mm), and daily average radiation (μmol m−2 s−1). Arrows indicate baby leaf harvest (Stage I), 27 (2016) and 29 (2017) days after sowing (DAS). End of data points indicate harvest at Stage II (baby leaf re-growth and intact plants) 40 and...

Recently, new annual and biennial cultivars of rapeseed with white flowers have been introduced to the baby leaf market. The white flower trait has been bred into modern cultivars of yellow flowering rapeseed. In baby leaf production, it is common practice to perform several cuts of the same plants, thereby harvesting regrown material. Seven white...

Human consumption of rapeseed (Brassica napus L.) sprouts and seedlings is not common but with the development of new white-flowering cultivars, this has become a possibility. Therefore, we investigated the effect of two blue/red light ratios (low blue (LB) and high blue (HB)) provided by light emitting diodes (LED) on glucosinolate (GLS), total ca...

A greenhouse experiment with parsley was conducted to investigate the effects of organic liquid fertilizers on biomass yield, photosynthesis, root zone pH and electrical conductivity (EC), and nutrient concentrations of plant tissue and growing medium. Limed peat with 20 kg m-3 composted chicken manure was used as the growing medium. Four organic f...

Nitrate leaching can be high in organic vegetable production. Late-harvested crops like leek limit the use of autumn catch crops. The aim of this study was to investigate the growing of a combination of a deep-rooted catch crop and a shallow-rooted vegetable to reduce the risk of nitrate leaching. We compared a leek sole crop (S) with two intercrop...

The effects of living mulch (LM) introduction and management strategies on cash crop yield, product quality and energy use were studied in a wide range of European vegetable cropping systems, climatic and soil conditions, as well as species of LM grown as agro-ecological service crops. Nine field experiments were carried out in research stations an...

The effect of introduction strategy for living mulches (LMs) to reduce the potential nitrate leaching was investigated when grown with vegetables with high nitrogen (N) demand and low use efficiency in four European countries: Italy, Slovenia, Germany and Denmark over 2 yr. The plant N uptake and soil nitrate N content at harvest, in the autumn, an...

Cauliflower (Brassica oleracea L. var. botrytis) has high nitrogen (N) demand during growing, but due to its low N use efficiency and N-rich residues, it may cause N losses by leaching after harvest. A field experiment was conducted to investigate the effect of overwintering grass-clover as an intercrop and moderately reduced N fertilization on org...

The effect of a ‘cover crop–vegetable cash crop’ intercropping system on arthropod dynamics and biodiversity, was investigated in four different European countries (Italy, Denmark, Germany, and Slovenia), by means of two-seasonal experiments. The soil arthropod fauna was used to compare the ecosystem services of living mulched systems with sole cro...

The aim of this study was to investigate the effect of growing in-season agro-ecological service crops as living mulch (LM) with vegetable crops, exploiting their potential to suppress weeds by filling the ecological niches otherwise occupied by weeds. Two field experiments were carried out in Denmark and Italy to compare different LM introduction...

tEnvironmental protection and human health have recently become important factors when selecting foodproduction systems. The wide usages of pesticides and synthetic fertilisers in conventional productioncause environmental pollution and degradation. Cover crops can reduce the use of external inputs suchas pesticides and fertilisers and can at the s...

The nitrate (N) present in soil at the end of autumn is prone to leach during winter and spring in temperate climates if not taken up by plants. In Denmark catch crops are used as a regulatory tool to reduce N leaching and therefore a shift from winter cereals to spring cereals with catch crops has occurred. Quantitative data is missing on N leachi...

The eating quality of carrots (Daucus carota L.) was investigated to evaluate the impact of cropping systems (one conventional and three organic systems) and growing years (2007, 2008, and 2009) on root size, chemical composition, and sensory quality. The content of dry matter, sugars, polyacetylenes, and terpenes as well as the sensory quality and...

We investigated how concentrations of sensory relevant compounds: glucosinolates (GLSs), flavonoid glycosides, hydroxycinnamic acid derivatives and sugars in kale responded to split dose and reduced nitrogen (N) fertilization, plant age and controlled frost exposure. In addition, frost effects on sensory properties combined with N supply were asses...

Metarhizium spp. have recently been shown to be associated with the roots of different plants. Here we evaluated which Metarhizium species were associated with roots of oat (Avena sativa), rye (Secale cereale) and cabbage (Brassica oleracea), common crop plants in Denmark. Thirty-six root samples from each of the three crops were collected within a...

Quality traits are highly focused upon in the marketing of organic food products. There is a need to define and measure quality as consumers seem to have preconceived notions about the superior health value and taste of organic compared to non-organic products. A commonly held opinion among many consumer groups is that organic farming guarantees op...

The objectives were to investigate if genetic diversity among field-grown traditional and F1 hybrid kale cultivars were reflected in different agronomic characteristics and consequently glucosinolate (GLS) and flavonoid glycoside concentration. We evaluated how nitrogen (N) and sulfur (S) supply and biomass allocation modified phytochemicals in two...

Living mulch management may have an effect on production of the crop and nutrient competition between the plant species in the field. In this paper, the amount of soil mineral nitrogen (N) available in the top soil during the cauliflower growing cycle and N uptake of the different components of the system were determined in two experimental sites i...

Two field experiments were carried out in order to test the effect on weed management of living mulch introduction in organically managed cauliflower (Brassica oleracea L.) in Central Italy and leek (Allium porrum L.) in Denmark. Burr medic (Medicago polymorpha L.) and Dyers Woad (Isatis tinctoria L.) were sown as living mulch in Central Italy and...

Split dose nitrogen (N) and sulfur (S) applications are a common agricultural practice as safe choices for environmental purposes. However, the effects of split dose practice on glucosinolate (GLS) biosynthesis remain elusive. The objectives of the present study were to investigate the timing effects of N and S fertilizer use on GLS biosynthesis in...

The drought stress tolerance of two blackcurrant cultivars (Ribes nigrum L., ‘Narve Viking’ and ‘Ben Gairn’) during the flowering period and their ability to recover following drought stress were studied by examining the effects of drought stress on growth and various physiological traits. The experiment was conducted under greenhouse conditions, a...

The aim of this review is to provide an update on factors contributing to quality of carrots, with special focus on the role of pre- and postharvest factors and processing. The genetic factor shows the highest impact on quality variables in carrots, causing a 7-11-fold difference between varieties in content of terpenes, β-carotene, magnesium, iron...

Studies on health effects of organic (ORG) products are still limited and often contradictory. We have investigated the impact of ORG and conventional (CV) carrots from two consecutive harvest years on mouse peripheral and intestinal immunity. Danish carrots (Bolero variety) were grown in three ORG (O1, O2 and O3) and one CV cropping system (D-CV)....

There is a need to advance the study of the effects of organic and conventional systems on product quality. In particular, little is known about the importance of different farming practices concerning nutrient cycling and the use of external inputs within organic farming for the quality characteristics of the products. In this study the quality ch...

Field and greenhouse pot experiments were conducted to evaluate the potential to use intercropping as an alternative method to increase glucosinolates in Brassicas by manipulating nitrogen (N) and sulfur (S) balance by intercropping with lettuce (Lactuca sativa L. var. capitata). In both experiments, four combinations of N and S fertilization were...

Mushrooms are the only non-animal food source of vitamin D. Wild mushrooms have naturally high vitamin D(2) content, and cultivated mushrooms produce vitamin D(2) from ergosterol when exposed to supplementary UV-B during the post-harvest phase. This study investigated the effects of providing supplementary UV-B during the growth phase on vitamin D(...

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...

Rep. N-TOOLBOX KBBE-2008-1-2-08

In 2008 the European Commission released a call for proposals under the workprogramme topic: novel approaches for reducing nitrogen losses. The objective of the programme was to improve uptake of the Nitrates Directive at the farm level. The consortium (Newcastle University, Louis Bolk Institute, Technical University of Madrid, and Aarhus Universit...

Poster presentation at International symposium

Poster presentation at International symposium

This paper reviews the knowledge on crowberry (Empetrum nigrum ssp. nigrum and ssp. hermaphroditum) dominated ecosystems in the Nordic region. Empetrum leaves and litter have high phenolic content resulting in slow decomposition, and with the formation of an organic top soil, nutrients are kept in an organic nutrient bank in the soil mainly availab...

In two field experiments, growth of white cabbage in pure stands was compared with that of cabbage grown in living mulch systems to reduce pest attacks. The roots of the living mulch were pruned early in the season, with the aim of reducing competition and increasing growth of the white cabbage. Root pruning was shown to increase the above-ground b...

Information is needed about root growth and N uptake of crops under different soil conditions to increase nitrogen use efficiency in horticultural production. The purpose of this study was to investigate if differences in vertical distribution of soil nitrogen (Ninorg) affected root growth and N uptake of a variety of horticultural crops. Two field...

Root development in beetroot (Beta vulgaris L. ssp. vulgaris var. conditiva Alef.), sweet corn (Zea mays L. convar. Saccharata Koern.) and celeriac (Apium graveolens L. var. rapaceum Gaud.) was followed during two growing seasons with the aim of describing the root systems and nitrogen (N) utilisation of the three vegetables. The crops were grown a...

Predicted changes in climate may affect key soil processes such as respiration and net nitrogen (N) mineralization and thus key ecosystem functions such as carbon (C) storage and nutrient availability. To identify the sensitivity of shrubland soils to predicted climate changes, we have carried out experimental manipulations involving ecosystem warm...