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There is an urgent need to analyse the term soil quality in more detail. Most frequently, it is used to describe soil attributes. The term should be used for this purpose only when related to the sustainability concerns (i) soil productivity, (ii) impact on the environment, and (iii) effect on human health. The soil quality concept has been adopted mainly as a technical framework for grading soil and evaluating management effects. We advocate more focus on soil quality as a cognitive concept associated with sustainability. Grading of soils by indicators is difficult across soil types, climates and cropping systems. The indexing of soil quality indicators introduce a significant loss of information on the complex agroecosystem. The contributions to the present book show that it is generally not possible to identify simple thresholds for sustainable farming neither at the soil quality indicator level nor at the management level. More adequate means of communicating management prescriptions to farmers and other decision makers in society are needed. Decisions should be based on knowledge on management effects on individual soil types as well as on stochastic and mechanistic models simulating soil processes and functions. Teams of researchers and stakeholders are needed in a joined effort towards optimal decisions. This calls for well-educated farmers and consultants. Scientific contributions towards sustainable farming should be based on combinations of on-farm system studies and analyses of specific soil functions. The main purpose of on-farm studies is to develop that particular system rather than to compare it with other systems. System studies may enable identification of emergent properties, which are important in system development and in identifying gabs in our understanding of the soil ecosystem. There is an urgent need to communicate scientific results with explicit expressions of sustainability priorities. This is to facilitate transfer of results from agricultural research and to encourage scientists to cope with the precautionary principle, adduced by environmentalists and other concerned citizens.

The paper outlines the current knowledge concerning fate of mycotoxins in the soil environment, including - outline of mycotoxins addressed (trichothecenes, zearalenone, fumonisins, aflatoxins, ochratoxins and patulin) - routes by which the mycotoxins enter the soil environment - routes by which they are immobilised or removed from the soil environment - mycotoxigenic fungi and mycotoxins in the soil environment

Management-induced depletion in soil organic carbon (SOC) may create critical tilth conditions for arable farming. We investigated the short-term effect of crop rotation and addition of animal manure on SOC fractions, the dispersibility of soil clay, the length of fungal hyphae, wet aggregate stability, tensile strength of dry aggregates, and the pore size distribution, gas diffusivity and permeability of undisturbed bulk soil. SOC fractions were measured in whole-soil samples and in 1-2 mm air-dried aggregates. Plough layer soil was sampled five and six years after the start of a field experiment with different cropping systems at two loamy sand soils (Foulum, ~9% clay and Flakkebjerg, ~14% clay). A soil drop test was performed in the field to evaluate in situ soil friability. A system dominated by small grain cereals not receiving animal manure served as a reference treatment (‘CEREAL’). This system was compared to the same crop sequence but with application of animal manure (‘CEREAL+MANURE’, only at one location), and to a diversified crop rotation including grass/clover but without addition of animal manure (‘CEREAL+GRASS’). A part of each field plot was compacted by a medium-sized tractor. The content of SOC was lowest for the CEREAL system at both locations. Hot-water extractable SOC displayed the same pattern. The carbon fractions in aggregates responded similarly to cropping systems as those in whole-soil samples. Clay dispersibility was highest in the CEREAL system. The length of fungal hyphae was enhanced by the versatile crop rotation. Soil compaction tended to increase clay dispersibility. Our results confirmed agronomic observations that the tilth in the Flakkebjerg soil was problematic and worse than in the Foulum soil, but generally only trends were found in amelioration of the poor mechanical tilth characteristics. In contrast, soil (macro)porosity was significantly higher for the CEREAL+GRASS system compared to the other two systems, and the CEREAL+MANURE and CEREAL+GRASS systems had more tortuous pore systems compared to the CEREAL system and better resisted compaction than the latter. We conclude that only 5-6 years of differentiated soil management significantly affected SOC fractions, the dispersibility of clay, and the growth of fungal hyphae. As only trends were found in the mechanical aspects of soil tilth, the tilth-forming agents may serve as early indicators of changes in soil tilth. Our results also indicate that soil pore characteristics are affected by short-term management and probably provide the basis for later significant changes also in mechanical tilth characteristics.

This Research Note concludes that both drum drying and ordinary continuous drying efficiently dry the grain but that drum drying is much more efficient in reducing the number of surface dwelling fungal propagules on the grain, both yeasts and filamentous fungi. This includes the toxigenic species, Fusarium culmorum, as well as other fusaria. It also includes the dark filamentous fungi, Alternaria infectoria and Cladosporium spp. Both drying techniques seemed to stimulate growth of Eurotium spp., probably due to heat activation of ascospore germination.

Artiklen giver eksempler på hvor vigtigt det er at tørre vådt korn hurtigt, hvis man skal undgå problemer med ochratoksin

Brug gennemløbstørreri til meget vådt korn. Korn fra plantørreri indeholder mere og oftere ochratoksin end korn fra gennemløbstørreri

New experiments have shown that grain moisture is more important than temperature for the formation of the mycotoxin Ochratoxin A (OTA). OTA is one of the most important mycotoxins on Danish grain. A fast and efficient drying procedure avoiding pockets of wet grain is crucial in preventing OTA formation.

En tung og knoldet jord er vanskelig at bearbejde. Det kan medføre et dårligt såbed og dårlig fremspiring. Og da en sådan jord også har få porer begrænses transporten af vand og ilt til planternes rødder. Herved forringes leveforholdene smådyr og mikroorganismer og der bliver en dårligere forsyning med næringsstoffer til planterne. For at få et godt såbed skal jorden have en god struktur – den skal gerne danne krummer (aggregater). De bygges op af jordens grunddele eller 'primærpartikler' ler og sand. Til at binde primærpartiklerne sammen kræves bindemidler. I danske jorde er biologiske bindemidler de vigtigste. Der findes to slags. Det ene er klisterstoffer, der dannes af planterødder, bakteri-er og svampe. Det andet er svampetråde (hyfer), der sammenvæver små krummer til større krummer. Leret selv kan også være bindemiddel, og det samme kan forskellige uorganiske forbindelser. I klummen beskrives resultater af undersøgelser på økologisk og konventionelt dyrkede jorde.

Råd om forebyggelse af ochratoksin problemer under post-harvest håndtering af korn

Analyser af knap 100 kornprøver viser at en hurtig og billig testmetode giver resultater, der stemmer godt overens med en mere kompliceret metode til måling af ochratoksin fra svampe. Den simple metode kan anvendes både til forskning og til egenkontrol i mindre virksomheder.

Nye forsøg har vist, at kornets vandindhold har større betydning end temperaturen for dannelse af giftstoffet ochratoksin. I forebyggelsen er det derfor altafgørende at få kornet tørret hurtigt ned og undgå fugtige lommer.

This study addresses the relationship between the ochratoxigenic strains of Penicillium verrucosum and ochratoxin A (OTA) contents in organically cultivated grain. It included 37 combined, non-dried grain samples from farmers with no drying facilities as well as 19 non-dried and 22 dried samples from six farms with on-farm drying facilities (Case studies 1-6). The study focused on the ancient wheat type spelt but also included samples of wheat, rye, barley, oats, triticale, emmer, and einkorn. All 78 samples were analysed for moisture content (MC) and occurrence of P. verrucosum. The latter was assessed by plating non-disinfected kernels on DYSG agar and counting those contaminated by the fungus. Fiftyfive samples were analysed for OTA. Most of the combine harvested samples (82%) were contaminated with P. verrucosum prior to drying. This was ascribed to difficult harvest conditions and many samples of spelt, which was significantly more contaminated by P. verrucosum than oats, wheat and barley. Though not statistically significant, the results also indicated that spelt was more contaminated than rye, which is usually regarded the most sensitive small grain cereal. No correlation was found between number of kernels contaminated by P. verrucosum and OTA content. Despite many non-dried samples being contaminated by P. verrucosum, only two exceeded the EU maximum limit for grain (5 ng OTA g-1), both being spring spelt with 18 and 92 ng g-1, respectively. The problems were most likely correlated to a late harvest and high MC of the grain. The case studies showed exceedings of the maximum limit in a batch of dried oats and spring wheat, respectively, probably to be explained by insufficient drying of late harvested grain with high MC. Furthermore, our results clearly indicate that OTA is not produced in significant amounts in samples with MCs below 17%. All dried samples with MCs above 18% exceeded the 5 ng OTA g-1 limit in grain. However, no correlation between MC and the amount of OTA produced was found.

Samspil mellem kornets temperatur og vandindhold er undersøgt. Det er påvist, at P. verrucosum kan vokse og danne ochratoksin ved temperaturer helt ned til 2 grader. Våde høstår kræver særlig stor omhu med tørring. Tromletørring har vist sig som en god metode til at eliminere sporer af P. verrucosum.

Når jordbundens mikroorganismer og smådyr har det godt, er jorden som regel også god at dyrke planter i. Og jordbundens levende organismer trives, hvis de får rigeligt med næring og fred og ro. Det første kan økologiske jorde levere, men på grund af mekanisk ukrudtsbehandling ofte ikke det sidste. En mindre del af de konventionelt dyrkede marker giver jordbundsorganismer lige så gode betingelser, så økologisk dyrkning er ikke en absolut betingelse for et godt jordliv.

Ligesom der findes vandkvalitet, luftkvalitet og fødevarekvalitet, findes der jordkvalitet. Og jordens kvalitet hænger nøje sammen med dens struktur, f.eks. dens indhold af partikler og porer. Dette kapitel handler om, hvordan økologisk og konventionelt landbrug påvirker jordkvaliteten. På nogle områder er økologisk landbrug bedst, men ikke på alle.

Subsoil compaction affects all aspects of soil quality and, contrary to topsoil compaction, it is persistent. Natural alleviation processes such as wetting/drying, freezing/thawing and biological activity, including root growth, decrease rapidly with depth. In compacted soil, these alleviation processes are moreover diminished because root growth and biological activity are reduced and soil water contents remain higher in compacted than in well-structured soil. Wheel loads are still increasing and, in consequence, so are the extent and severity of subsoil compaction. Sustainable soil management requires the uncompromising criterion that no subsoil compaction can be accepted. Consequently, only field traffic with wheel loads lower than the carrying capacity of the subsoil is allowed. This implies that subsoil stress caused by wheel load should not exceed the strength of the subsoil. Therefore, this chapter emphasizes the importance of soil strength and the calculation of soil stresses in the subsoil. One of the main constraints in using the carrying capacity concept proves to be the lack of data on soil strength. Existing recommended limits for wheel loads and inflation pressures are not adequate and can result in over- or underestimation of allowable wheel loads and subsequent uneconomical solutions or subsoil compaction. Adequate drainage of soils is a prerequisite for reduced subsoil compaction. Mouldboard ploughing with all tractor wheels on the non-ploughed 'land' and umbilical systems for applying manure slurry are realistic options to reduce compaction. Controlled traffic systems that limit the wheeled area may be implemented by the use of wide-span vehicles and by steering tractors along traffic lanes. Although we support such provisions, our chapter will advocate and focus primarily on adjusting wheel loads to the carrying capacity of the subsoils.

Summary The industrialization of agriculture and the concurrent increase in societal concerns on environmental protection and food quality have put the focus on agricultural management and its impact on soil quality. Soil quality involves the ability of the soil to maintain an appropriate productivity, while simultaneously reducing the effect on the environment and contributing to human health. This development has changed society's expectations of science and there is an urgent need to improve the communication among researchers from different scientific disciplines. The interaction of scientists with decision makers is a topic of utmost relevance for future developments in agriculture. Reflexive objectivity denotes the exercise of raising one's consciousness of the cognitive context, i.e. societal priorities, and the values and goals of the researcher. The term sustainability comprehends the priorities in the cognitive context and thus constitutes a valuable tool for expressing the basis of scientific work. Soil quality evaluations should include aware- ness of the stability of any given quality attribute to disturbance and stress. This implies addressing resis- tance and resilience of the soil functions and/or the physical form in question. Most existing literature on soil quality focuses on assessment of soil quality rather than the management tools available to influence soil quality. Identification of management thresholds rather than soil-quality indicator thresholds is suggested as an important means of implementing the soil quality concept. The major challenges facing modern agriculture include proper nutrient cycling, maintained functions and diversity of soil, protection of an appropriate physical form and avoidance of chemical contamination. It is suggested that these challenges and problems as related to the soil quality concept are discussed in the framework expounded above.

The availability of nitrogen to crop plants is a universally important aspect of soil quality, and often nitrogen represents the immediate limitation to crop productivity in modern agriculture. Nitrogen is decisive for the nutritive value of plant products and plays a key role in the environmental impact of agricultural production. The fundamental doctrine of nitrogen management is to optimise the nitrogen use efficiency of both introduced and native soil nitrogen by increasing the temporal and the spatial coincidence between availability and root uptake of mineral nitrogen. Natural ecosystems have evolved to produce a high degree of coincidence and maintain a relatively tight nitrogen cycle. The management needed to assure the vitality of crop cultivars with a high production potential cause agroecosystems to be relatively open with respect to nitrogen. By shifting the focus from sheer productivity to a balance between productivity, product quality and environmental impact, the management of agroecosystems can be redesigned to allow for a higher nitrogen use efficiency. The important management measures to improve the nitrogen aspect of soil quality are crop sequences that incorporate cover crops, judicious use of soil tillage, improved timing and use of animal manures, crop residues and mineral fertilizers, and a sustainable balance between plant production potential and animal stocking density. This chapter addresses the characteristics of nitrogen cycling in plant production, the premises upon which an improved nitrogen use has to be based, and discusses management principles that can improve nitrogen use in cropping systems.

Soil structure is an important element of soil quality since changes in structural characteristics can cause changes in the ability of soil to fulfil different functions and services. Emphasis in this chapter is placed on the role of soil structure in biological productivity of agroecosystems. Combinations of management practices in which the extent of the degradation of soil structure caused by one practice is balanced or exceeded by the extent of regeneration by other practices will help sustain the productivity of agroecosystems. Tillage and practices that change the organic matter (OM) content of soil are foremost among the many practices that influence soil structure. The links between management, OM content and soil structure and between tillage and soil structure are explored. The feasibility of defining management thresholds or soil quality indicator thresholds with respect to soil structure is assessed.

During the last decades Denmark has experienced a growing interest in low-input farming systems like organic farming. These systems rely on a high soil fertility to maintain nutrient availability and plant health. Soil aggregation contributes to this fertility, because it is crucial to soil porosity, aeration and infiltration of water. This paper reports a study of two pairs of differently managed, neighboring fields. The aim was to elucidate long-term effects of the different farming systems on physical and biological variables with influence on bonding and binding mechanisms of soil aggregation. Each pair consists of an organically grown dairy farm soil, based on a forage crop rotation system, including grass (Org-FCS(G)) and a conventionally managed soil. One of the conventional farms has a forage crop rotation with annual cash crops and no grass (Conv-FCS(NG)) and one has been grown continuously with small grain cereals and rape (Conv-CCS). Our results indicate that the Org-FCS(G) soils stimulate biotic soil aggregating agents as measured by extracellular polysaccharides (EPS) and hyphal length measurements, respectively. Generally, the Conv-CCS soil, which relies exclusively on synthetic fertilisers and cereal production, offered poor conditions for the biotic binding and bonding agents. Nevertheless this soil contained a large amount of stable macro-aggregates. This is explained by the physical results, which indicated that the strong macro-aggregation was due to clay dispersion and cementation processes rather than to biotic processes.