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Large sized biopores (diameter >2 mm) in the subsoil can be created by tap roots, which leave voids after their decay, or by the burrowing activity of anecic earthworms which may benefit from the temporary lack in tillage in perennial cropping systems. However, the interactions between root growth and earthworm activity in the process of biopore formation during perennial ley cropping are not well understood. The aim of this field study was to quantify the development of the abundance of the anecic earthworm Lumbricus terrestris and the biopore density during the cultivation of lucerne (Medicago sativa L.), chicory (Cichorium intybus L.) and tall fescue (Festuca arundinacea Schreb.) grown for either one, two or three years. An increased abundance of L. terrestris was already recorded after two years of continuous ley when compared with one year cultivation. The ley crop species had only minor influence on the abundance of L. terrestris. Biopore densities of both diameter classes under study (2–5 mm and >5 mm) were not significantly affected by the duration of ley cropping. In contrast, biopore densities were influenced by ley crop species. More biopores of diameter class 2–5 mm were recorded after chicory than after fescue. Lucerne cropping resulted in intermediate biopore density. Additionally, in an incubation experiment under field conditions, we quantified whether L. terrestris preferentially created new biopores or colonized abandoned, previously existing ones. After three weeks of incubation, one third of the adult individuals incubated in the experimental area created new biopores at 0.4 m soil depth. A similar percentage of individuals colonized previously existing biopores, partially widening the lumen of smaller sized biopores. The remaining individuals remained in the topsoil. Sub-adult individuals rarely formed new pores. Half of the introduced sub-adults remained in the topsoil. We conclude that

In arable farming systems, the term ‘subsoil’ refers to the soil beneath the tilled or formerly tilled soil horizon whereas the latter one is denoted as ‘topsoil’. To date, most agronomic and plant nutrition studies have widely neglected subsoil processes involved in nutrient acquisition by crop roots. Based on our current knowledge it can be assumed that subsoil properties such as comparatively high bulk density, low air permeability, and poverty of organic matter, nutrients and microbial biomass are obviously adverse for nutrient acquisition, and sometimes subsoils provide as little as less than 10% of annual nutrient uptake in fertilised arable fields. Nevertheless, there is also strong evidence indicating that subsoil can contribute to more than two-thirds of the plant nutrition of N, P and K, especially when the topsoil is dry or nutrient-depleted. Based on the existing literature, nutrient acquisition from arable subsoils may be conceptualised into three major process components: (I) mobilisation from the subsoil, (II) translocation to the shoot and long-term accumulation in the Ap horizon and (III) re-allocation to the subsoil. The quantitative estimation of nutrient acquisition from the subsoil requires the linking of field experiments with mathematical modelling approaches on different spatial scales including Process Based Models for the field scale and FunctionaleStructural Plant Models for the plant scale. Possibilities to modify subsoil properties by means of agronomic management are limited, but ‘subsoiling’ e i.e. deep mechanical loosening e as well as the promotion of biopore formation are two potential strategies for increasing access to subsoil resources for crop roots in arable soils. The quantitative role of biopores in the nutrient acquisition from the subsoil is still unclear, and more research is needed to determine the bioaccessibility of nutrients in subsoil horizons.

The hygienic quality of head lettuce (Lactuca sativa L.) was investigated after different fertilizer treatments (fresh farmyard manure, composted farmyard manure, stinging nettle extract and calcium ammonium nitrate) in a 2-year field experiment with two trials per year, respectively. For assessment of the hygienic quality the total aerobic bacterial counts, Enterobacteriaceae, coliform bacteria, Escherichia coli and Salmonella were investigated in soil, fertilizer and lettuce samples. Plants were washed with running tap water before analysis. The total aerobic bacterial count, as well as the levels of Enterobacteriaceae and coliform bacteria tended to be slightly higher (not significant) after organic compared to mineral fertilization. No Salmonella was detected in any soil, fertilizer or lettuce sample, while E. coli was randomly detected in low concentrations independent from fertilizer treatment. No higher risk of bacterial contamination due to the use of organic fertilizers was indicated. (c) Elsevier

Brochure met informatie over onderzoek naar ondergewassen in de biologische aardappelteelt. Het gebruik van een ondergewas kan de onkruiddruk verminderen en leiden tot een vermindering van de hoeveelheid restnitraat.

Mycotoxins are toxic metabolites formed by specific fungi that grow on living plants and their residues under favourable conditions. They are undesirable ingredients of food and feed. Risks are also posed by the spores and toxin-contaminated raised dusts. Contamination by mycotoxins is a severe problem in food security. More than 300 species of fungi with the ability to form mycotoxins have been identified. More than 400 metabolites are assigned to the group of mycotoxins. Fortunately, only about 20 mycotoxins produced by five genera of fungi (Fusarium, Penicillium, Claviceps, Alternaria and Aspergillus) are found regularly or periodically in food and feed at levels which might have an impact on human and animal health (Gareis, 1999a). Since synthetic fungicides are not allowed in Organic Agriculture, fungal populations are often presumed to be higher in this farming system, and a higher frequency of mycotoxin contamination of organic food and feed has frequently been postulated by Tinker (2001). Others argued that omitting fungicides might lead to higher diversification of microbial populations and therefore limit growth of specific mycotoxin producers. There are controversial reports on varying mycotoxin contamination levels of grains produced organically and in mainstream farming (Marx et al., 1995, Berleth et al., 1998, Birzele et al., 2002, Meier et al., 1999, Stähle et al., 1998, Döll et al., 2002). Thus, the first aim of this contribution is to analyse whether a higher occurence of mould on organically grown crops and, as a result, a higher risk of mycotoxin impact due to specific organic farming as well as low input farming methods is confirmed by the reviewed literature. Secondly, factors that may influence mycotoxin contamination in the different cereal production systems are highlighted. Finally, strategies to reduce mycotoxin contamination are described. The recommendations given are limited to the conditions of the temperate European climate.

Vorbeugende und alternative Maßnahmen der Unkrautregulierung zur Erhaltung der Pflanzengesundheit.

In 1997 a crop rotation experiment was initiated at three sites in Denmark. The objective of the experiment was to explore the possibilities for both short-term and long-term increases in organic cereal production through manipulation of crop rotation design on different soil types. The experiment included three factors (proportion of grass-clover in the rotation, catch crops and manure application) in a randomised factorial design. The main indicators measured in the experiment were crop yield, nutrient leaching and weeds. The crop rotation experiment has shown significant effects of location, crop rotation, catch crops and manure on yields, weed infestation, soil fertility and nutrient losses (Olesen et al., 2002; Schjønning et al., 2004; Askegaard et al., 2005a, b; Rasmussen et al., 2005, 2006). There were indications of changes of some of these effects over time as a result of the ‘buffering power’ of grass-clover, where the N2-fixation is affected by crop management and soil fertility. This buffering power will probably not only affect yields but also the risk of N losses, and there is a need to further investigate possibilities of controlling N supply to the crops better through improved use of green manure crops, catch crops and manure at the crop rotation level. Perennial weeds (especially C. arvense and E. repens) have proliferated severely in the crop rotation experiment at two of the three locations during the experimental period, and these weeds may seriously reduce yields in organic arable farming. Direct control of perennial weeds is typically carried out by stubble cultivation in autumn, reducing the possibilities for growing catch crops. The energy use, as well as the elevated risk for nutrient leaching, jeopardizes the sustainability of this practice, and therefore cultivation should be avoided (Rasmussen et al., 2006). The crop rotation experiment has shown that the occurrence of these weeds is significantly affected by the choice of crops and catc

The aim of this 5 year investigation was to compare quality parameters of differently cultivated carrots of the same cultivar grown in the same region as well as to compare the relevance of different methods of analysis to differentiate between these products. The following quality tests were applied: • Sensory tests (all harvests) • Food preference tests with laboratory rats (all harvests) • Decomposition tests (all harvests) • P-value determination (all harvests) • Single-Photon-Counting (1999) • Chemical analysis of the main components (1998 and 1999) It could be shown that carrots (var. Tarvil) grown using an organic farming method were significantly preferred by humans and laboratory rats, lost significantly less dry matter during decomposition, had lower P-values, indicating better bioelectrical properties, revealed a significantly better capacity to store biophotons, but showed no conclusive differentiation concerning their main components. Holistic methods were well qualified to distinguish organic from conventional carrots on significant levels.

Fifty spring barley varieties grown under organic as well as conventional growing conditions in experimental fields in four combinations of year and site were studied. The yield varied much within and between environments (years and sites) and systems. Further, the variation between varieties was substantially and it differed between different environments and systems. Associations between observed grain yield of these varieties and disease and growth characteristics assessed in the official conventional variety testing were compared between the organic and the conventional system. Using factorial regression analysis, the best model for predicting the observed grain yield each year from these characteristics the previous year was found. In this model, the residual variance component for varieties was lower for observations from the conventional growing system than from the organic growing system implying that the VCU-characteristics better predicted the results from conventional growing system. The implications for organic variety testing are discussed.

Intercropping (IC) is the simultaneous cultivation of more than one crop species on the same piece of land. The IC practice offers many advantages to organic agriculture in terms of resource use, yield stability, weed management and increased diversification of agroecosystems. Field experiments carried out at two sites in Denmark over three consequetive cropping seasons showed that ICs of cereals and grain legumes gave higher yields, less weeds, lower infection with plant diseases and higher grain quality compared to corresponding sole crops.

Combinations of three different direct methods for controlling Vicia hirsuta (kainite application, flame weeding and harrowing) were investigated in field experiments. They were based on different strategies at early growth stages of V. hirsuta and standardised harrowing at late growth stages. The highest efficacy of kainite application and flame weeding was achieved at the one leaf stage of V. hirsuta. Winter wheat regeneration from damage caused by both kainite and thermal control was satisfactory when treatments were applied at early growth stages (GS 23). Vicia hirsuta plants that survived kainite application or flame weeding were successfully controlled by repeated harrowing at later crop growth stages; crop growth was not affected. Seed production of V. hirsuta declined with increasing harrowing in all treatments; however the strongest and most reliable reduction was achieved when flame weeding had been previously applied. All combinations of direct measures reduced winter wheat grain-yield losses and enhanced thousand-grain weight more efficiently than the use of a single method only. The highest wheat-grain yield was gained after repeated harrowing (3 times) both with and without kainite application.

In long-term organic crop rotation experiments for cereal production, stubble cultivation to control perennial weeds increased nitrogen leaching compared to catch crops grown after harvest. Stubble cultivation contributed to the control of Elymus repens on a sandy soil, but not to the control of Cirsium arvense on a loamy soil. Manure application had a tendency to decrease E. repens density in one rotation at the sandy soil. Grass-clover green manure decreased C. arvense in the succeeding crops. Despite high infestations of perennial weeds, yields were at the same level with as without stubble cultivation. The results point to an important dilemma in organic farming: should the farmer control perennial weeds in the stubble at the expense of losing nitrogen by leaching? Or should catch crops be grown that preserve nitrogen, but allow E. repens to proliferate?

Ecological justice is a challenging concept in relation to the current development of agriculture, including organic agriculture, because it positions social and ecological interests against market liberalism and economic growth. Ecological justice concerns fairness with respect to common environments, and it is therefore closely connected to the idea of commons. The concepts of commons and ecological justice are particularly relevant to organic agriculture, which builds on close cooperation with ecological systems and cycles, and they may suggest ways to resist the pressures of globalisation and structural and technological developments.

Compared to single stubble tillage efficacy of C. arvense weed control was increased by repeated tillage independent of the tillage implements used. Competitiveness of a vigorous green manure can further enhance the effect of weed control.

Seed production of hairy tare was reduced by harrowing. Harrowing can be performed until ear emergence without severe damage of winter wheat. Efficacy of late and repeated harrowing was increased if combined with early harrowing (BBCH 32-33). The removal of V. hirsuta reduced winter wheat grain yield losses and enhanced thousand grain weight.

Die Rauhaarige Wicke (Vicia hirsuta) kann in konkurrenzschwachen Wintergetreidebeständen des Organischen Landbaus in hoher Dichte und Masse auftreten. Die Folge sind Ertrags- und Qualitätsverluste sowie Ernteerschwernisse. Informationen zur erfolgversprechenden Regulierung von Vicia hirsuta fehlen bislang weitgehend. In faktoriellen Feldversuchen zu Winterweizen und Winterroggen wurden das Verätzen der Wicken durch Einsatz von Kainit, die thermische Kontrolle sowie die mechanische Kontrolle (Striegel) in frühen und späten Entwicklungsstadien geprüft. Erfasst wurden Anzahl und Deckungsgrad der Wicken, die Schäden an der Kulturpflanze, Ertragsparameter (Kulturpflanze) und die Samenproduktion der Wicken. Die Ergebnisse aus den Versuchsjahren 2002 und 2003 zeigen, dass: (1) Vicia hirsuta in allen Stadien gegen das Verätzen mit Kainitlösungen empfindlich ist, wobei der Wirkungsgrad bei Anwendung im Jugendstadium am höchsten war. In den Feldversuchen war die Wirkung stark witterungsabhängig; das Getreide wurde durch die Kainitbehandlung nur geringfügig geschädigt. (2) Die Wirkung der thermischen Behandlung auf Vicia hirsuta war abhängig von der Intensität der Hitzeeinwirkung sowie den Entwicklungsstadien von Kulturpflanze und Wicke. Die Auswirkungen des Abflammens auf das Getreide waren bei der Anwendung vor Bestockungsende gering; das Getreide regenerierte sich vollständig. Bei Behandlungen nach der Bestockung des Getreides traten hingegen vglw. starke Schädigungen auf, die auch Ertragseinbußen verursachten. (3) Mit alleinigem Einsatz des Striegels ist eine effiziente Kontrolle von Vicia hirsuta erreichbar. Voraussetzung sind die rechtzeitige Bearbeitung während des Schossens und ggf. wiederholte Durchfahrten bis nach dem Ährenschieben.

Der Befall mit dem Erreger der Kraut- und Knollenfäule (P. infestans) hat durch frühzeitigen Verlust der Assimilationsfläche regelmäßig erhebliche Ertragsverluste im Ökologischen Kartoffelbau zur Folge. Neben einer Reihe von vorbeugenden Maßnahmen, inbesondere Wahl toleranter Sorten und Vorkeimen des Pflanzgutes (KARALUS 1995, MEINCK 1999), sind zur direkten effizienten Kontrolle derzeit nur Kupferverbindungen zugelassen. Ein weitgehend unerforschtes Potential zur Kontrolle dieses Oomyceten liegt in der Nutzung von Pflanzenextrakten, diese Wirkung wurde in Feldversuchen untersucht.

Die Rauhhaarige Wicke Vicia hirsuta tritt in Wintergetreidebeständen des Organischen Landbaus oft massenhaft auf und verursacht Ertrags- und Qualitätsverluste sowie Ernteerschwernisse. Indirekte Maßnahmen der Unkrautkontrolle reichen nur bei schwachem Unkrautdruck aus. Ziel der Untersuchungen war es, Strategien zu entwickeln, um Vicia hirsuta auch bei starkem Unkrautdruck effizient zu kontrollieren. Hierzu wurden drei Lösungsansätze verfolgt: Einsatz von Kainit, thermische und mechanische Kontrolle. In faktoriellen Feldversuchen in Winterroggen und Winterweizen wurden die mechanische Kontrolle in frühen (Hacke, Striegel) und späten Entwicklungsstadien (Striegel) sowie die thermische Kontrolle und das Verätzen durch Einsatz von Kainit geprüft. Aus dem ersten und dem laufenden zweiten Versuchsjahr ließ sich folgendes ableiten: 1. Zur Erstellung eines praxisrelevanten Kainit- Verfahrens sind weitere Untersuchungen zu Dosierung, Applikationstechnik und -zeitpunkt notwendig. 2. Der Ansatz der thermischen Kontrolle von Vicia hirsuta in Winterweizen ist vielversprechend und kann in Strategien zur nachhaltigen Kontrolle dieses Problemunkrauts insbesondere in Befallsnestern genutzt werden. 3. Mit dem alleinigen Einsatz des Striegels ist ebenfalls eine effiziente Kontrolle von Vicia hirsuta erreichbar. 4. In Winterroggen hingegen stehen zum Abflammen und Striegeln nur kurze Zeiträume zur Verfügung, so daß die Kontrolle von Vicia hirsuta wesentlich schwieriger und unsicherer als in Winterweizen ist.

Die Rauhhaarige Wicke (Vicia hirsuta) tritt in konkurrenzschwachen Wintergetreidebeständen des Organischen Landbaus oft massenhaft und ertragswirksam auf, so daß direkte Kontroll-maßnahmen notwendig werden. Informationen zur Kontrolle von Vicia hirsuta bei starkem Unkrautdruck fehlen bisher weitgehend. In faktoriellen Feldversuchen in Winterroggen und Winterweizen werden daher die mechanische Kontrolle in frühen (Hacken, Striegeln) und späten Entwicklungsstadien (Herauskämmen) sowie die thermische Kontrolle und das Verätzen durch Einsatz von Kainit geprüft. Im ersten und dem laufenden zweiten Versuchsjahr zeigte sich, daß sich Getreide nach thermischer Behandlung vor Bestockungsende gut regeneriert. Behandlungen nach der Bestockung des Getreides schädigten Vicia hirsuta nicht ausreichend. In Vorversuchen im Gewächshaus war Vicia hirsuta in allen Stadien gegen das Verätzen mit Kainit empfindlich, der Wirkungsgrad bei Anwendung im Jugendsta-dium am höchsten. Im Freiland war die Wirkung stark witterungsabhängig, d.h. nur bei hoher Verdunstung und Einstrahlung ausreichend. Eine effiziente mechanische Kontrolle von Vicia hirsuta erscheint in Winterweizen demnach möglich. Voraussetzung sind die rechtzeitige Bearbeitung während des Schossens und ggf. wiederholte Durchfahrten bis nach dem Ährenschieben.

Fixed nitrogen accumulated by legumes is the main nitrogen source for organic farming systems. Knowledge about the amount of fixed nitrogen, its pathways into forage yield, crop residues, soil-N and yield formation of the following crop is needed for designing crop rotations. Two field experiments were conducted in Northern Germany with differently managed (cut, mulched) legumes (red clover, alfalfa, white clover) in pure stands and various mixtures with two companion grasses (Lolium multiflorum, Lolium perenne) have been grown to determine N2-fixation, residue nitrogen and N-uptake of subsequent crops. Cropped grass/legume reached higher N2-fixation than mulched. While green manure grass/legume left up to 280 kg ha-1 of N in mulch, stubble and roots on the field, most cropped grass/legume mixtures left less than 110 kg N ha-1 in crop residues. Pure legume swards or legume rich mixtures showed higher N2-fixation than grass rich mixtures. N-uptake in late autumn and at maturity of the subsequent wheat was strongly correlated to the legume content in DM-yield.

The paper describes the organic vegetable crop rotation. The ideas behind the design of the crop rotation, the use of green manures and catch crops, and how information on crop root growth has been used to try to design a crop rotation with a high NUE and minimal N leaching losses. The results from the first years of the rotation, in terms of yield and N uptake of the crops and of the content of inorganic N in the soil are presented.

Schlussfolgerungen Unter der Einschränkung, dass die alleinige Betrachtung der N-Wirkung nur einen Teil des N-Haushaltes ausmacht (z.B. Einbau von N in den Humuskörper), können aus den vorliegenden Ergebnissen folgende Schlussfolgerungen gezogen werden: • Bei der aeroben Rotte bzw. Kompostierung von Mist wurden im Vergleich zur anaeroben Lagerung von Mist grössere N-Verluste gemessen, d.h. es wurde bei diesen Verfahren folglich weniger Stickstoff auf die Parzellen ausgebracht. • Bei der Anwendung auf dem Feld erzielten Rottemist und Mistkompost im Vergleich zu Stapelmist jedoch eine bessere N-Wirkung. Dies macht deutlich, dass bei der Beurteilung unterschiedlicher Mistformen neben N-Verlusten und N-Gehalten insbesondere die N-Wirkung (Mineralisierungseigenschaften) berücksichtigt werden muss. • Mit qualitativ hochwertigem Grünabfallkompost kombiniert mit Güllegaben konnten vergleichbare Erträge wie bei den ausschliesslich mit Hofdüngern gedüngten Parzellen erzielt werden. Die N-Wirkung ist dabei aber aufgrund des Holzanteils der Grünabfallkomposte deutlich tiefer als bei Rottemist und Mistkompost. • Mit Vollgülle wurden – bei leicht höherer N-Wirkung – ähnliche Entzüge wie mit Rottemist und Mistkompost erreicht.

Während für den Verbraucher organisch angebauter Kartoffeln der Geschmack, die Koch-eigenschaften und der Gesundheitswert maßgebliche Kaufkriterien darstellen, sind für den Anbauer das Ertragsniveau, die Ertragssicherheit und die Lagereignung wichtige Zielgrößen. Maßgebliche Einflußfaktoren auf diese Zielgrößen stellen die Sortenwahl und die Höhe der organischen Düngung dar. Im Rahmen eines von der Deutschen Forschungsgemeinschaft und der Eden-Stiftung finanzierten Projektes, an dem mehrere Institute der Universität Bonn beteiligt sind, werden an verschiedenen Standorten Feldversuche mit differenzierter Sortenwahl, Düngungshöhe und Düngungsart (mineralisch, organisch, biologisch-dynamisch) durchgeführt. Auf Grundlage der mit diesen Feldversuchen ermittelten Parameter der Ertragsbildung, Ertragsstruktur, inhaltsstofflichen Qualität und des Lagerverhaltens sollen Optimierungsstrategien in Hinblick auf die anfangs genannten Zielgrößen ent-wickelt werden. Es werden Ergebnisse des Sortenversuchs des Jahres 1996 zur Ertragsbildung, Ertragsstruktur und zu einigen qualitätsbeschreibenden Inhaltsstoffen der Kartoffel dargestellt.

Die Qualitätsbeurteilung pflanzlicher Produkte aus unterschiedlichen Anbauverfahren stößt immer wieder auf die gleichen Probleme: Nach SCHUPHAN (1961) setzt sich die Qualität eines Nahrungsmittels aus drei Haupt-eigenschaften zusammen: Äußere Beschaffenheit (z.B. Handelsklassen), Gebrauchswert (d.h. technische Verarbeitbarkeit) und biologischer Wert, welcher die Addition aller wertgebenden abzüglich der wertmindernden Inhaltsstoffe darstellt. Diese Summation der Inhaltsstoffe kann zur Qualitätsbeurteilung jedoch nicht ausreichen, da immer nur ein Bruchteil der Pflanze und nie die Pflanze als Ganzheit gesehen wird, ein Problem, welches schon des öfteren diskutiert wurde (u.a. KLETT, 1968; SCHORMÜLLER, 1974). In Untersuchungen, welche Rückschlüsse auf die Qualität eines Nahrungsmittels ermöglichen sollen, gibt es darüber hinaus des öfteren widersprüchliche Tendenzen. So kann es zum Beispiel durchaus vorkommen, daß durch physiologische Ungleich-gewichte innerhalb der Pflanze ein niedriger Gehalt freier Aminosäuren auftritt (erwünschtes Qualitätsmerkmal, da der Anteil an essentiellen Aminosäuren dadurch theoretisch höher ist [SCHUPHAN, 1976]), die biologische Eiweißwertigkeit jedoch trotz-dem gering ist. Eine Qualitätsaussage basierend auf nur einem oder wenigen Parametern ist daher unzureichend. Zudem dürfen die Unterschiede der einzelnen Parameter bei verschiedenen Anbauvari-anten nicht einfach zu einer Rangfolge zusammengefaßt werden, da die relative Höhe der Unterschiede dabei unberücksichtigt bliebe und geringe Unterschiede überbewertet würden. Eine Möglichkeit zum Entschärfen der genannten Probleme ist die Kondensation möglichst vieler Parameter zu einem „Qualitäts-Index“.

Adequately assessing the quality of food grown with different cultivation methods is a constant problem. According to SCHUPHAN (1961), food quality consists of three main characteristics: grading, technological quality and nutritional quality. The latter involves the ratio between beneficial and harmful substances. Yet it is obvious that more than merely summing various substances is needed to assess the quality of food properly. This problem has been previously discussed by SCHORMÜLLER (1974) and KLETT (1968). A concept of quality that embraces the plant as a whole (and the internal equilibrium of the individual components) requires bringing together the results of multiple investigations in an integrated accounting that registers even slight differ-ences. Examinations of food quality, moreover, have repeatedly tended to produce contradictory results. It may appear for example, that physiological imbalances within a plant create a low concentration of free amino acids - which is desirable since it theoretically implies a high concentration of essential amino acids (SCHUPHAN, 1976). However, the protein quality itself may remain low. Therefore, any statement concern-ing the quality of food which is based on a few parameters only proves to be insuffi-cient. Isolated approaches might lead to wrong conclusions. Also differences in parameters must not be summarized hierarchically because relatively small differences would become overestimated. The Quality Index, condensing as many parameters as possible in an integrated calculation, might provide a way out of this predicament.