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1.
Data from silage maize variety trials of the years 1999?C2010 in the Central German dry region were subjected to a secondary analysis using methods of mathematical statistics: With the phenological ripeness indicators (grain dry matter content/TM of the residual plant) the differences in the ripeness dynamics of grain to residual plant and their effects on the economy and ecology compared to the current ripeness system with use-specific ripeness numbers are documented. This dependence on all directions of use in the maize of the environments and varietal types taking into account of the different plasticity of maize varieties is been quantified. The achievement of physiological ripening of the grain is the interface of all usage directions and at the same time basis for the comparable, agro-eco-efficient level of maturity (63% TM) in conjunction with the silage ripeness index (SRI of 2.8) by eco-silage maize crops. The specific characteristics of the usage directions are low and with regard to efficiency, environmental and consumer protection discussed. With the phenological stage indicator (SRI) can both replaced the DM content of the whole plant as a parameter to the harvest date of silage and energy maize as the usage-specific ripeness numbers to the variety choice for silage and grain maize. A classification of the varieties according to ripeness groups would fully correspond to the environmental maize production. In the preparation of production (breeding, approval, testing and type of election), the SRI serves as selection and during inventory management through differential ripening control in compliance with the environmental and field production conditions as ripeness index. The wide ripeness ratio between grain and residual plant is the phenotypic expression of maize varieties as indicator for the agro-eco-efficiency and multifunctional guarantee better plant health, the resource efficiency, as well as basic product safety and sustainability of the process of maize silage. A precise fixing of harvest time point (HTP) is possible only with the SRI. The correct HTP is in principle maximum possible SRI. This HTP differently from the silage optimum can be according to the environments and the type of election. Ideally a maximum high SRI of 2.9 and over to a high basic intake of ground feed when reaching for exclusive maize silage feeding ruminant more friendly, better structural efficiency and grain hardness for the bypass of starch in the small intestine. The variety and the harvest strategy are to focus their reasons of economy and ecology on a high proportion of stocks ripeness in the field of silage optimum (SRI >?2.6) reach. Standard for maximum efficiency of production process maize and its environmental and consumer protection in the field of view of social line is the reaching of the agro eco-efficient ripeness point (SRI of 2.8 at physiological ripeness of grain by 63%).  相似文献   

2.
Intensive research on plant immunity revealed detailed knowledge on how plants recognize and defend plant pathogens. This knowledge is ready to use for genetic plant protection of crop plants, which does not rely on xenobiotic principals. Here, we report on important success in research on plant immunity and on recent and future possibilities of biotechnological plant protection that builds on intrinsic plant immunity.  相似文献   

3.
Ancient Egyptian insect relics were accidentally enclosed in embalming resin which leaked from a priest's mummy and solidified on the floor of a wooden coffin from the end of the XVIIIth Dynasty (presumably 1323–1295 BC). The preserved insect relics were blowflies (Calliphoridae) recognized as Chrysomya marginalis or Chrysomya megacephala whose larvae had developed by feeding on the deceased's body prior to mummification as well as furniture beetles (Anobiidae) being either Oligomerus ptilinoides or Priobium carpini whose larvae had ingested the coniferous wood of the coffin. It is most likely that the human corpse and coffin were first attacked by the blowflies and furniture beetles prior to embalming, while infestation of the insect remains and textiles by Anthrenus sp. (Dermestidae) occurred in our time.  相似文献   

4.
Tropospheric (ground-level) ozone is considered as one of the most important air pollutants affecting vegetation. It is a secondary pollutant formed from chemical reactions of primary pollutants (nitrogen oxides and volatile organic compounds) under the action of sunlight. While there is a clear trend of decreasing ozone peak values (?photosmog episodes??) in Europe, predictive models indicate that background ozone concentrations will continue to increase. Moreover, ozone concentrations are increasing rapidly in emerging economies worldwide. The widespread distribution of ozone already presents a risk to crop growth and health in many regions of the world. Ozone reduces plant productivity by entering leaves through the stomata, causing oxidative stress and decreasing photosynthesis, plant growth and biomass accumulation. Ozone causes visible injury symptoms to foliage, and decreases crop yield and yield quality, any or all of which can result in significant economic losses. However, there is a wide inter- as well as intraspecific variation in sensitivity to ozone. Important food crops such as wheat and soybean are highly sensitive to ozone, while potato, maize or sugar beet are considered to be less sensitive. Modification of the crops?? sensitivity by interactions of ozone with biotic and abiotic factors or by secondary effects of ozone are well documented but are poorly addressed in current risk assessments.  相似文献   

5.
The commercial available diatomaceous earth Fossil Shield® and the neem product Neem Azal-T/S® are tested as single treatments and in combination as controls for the stored product pests Sitophilus oryzae (L.) and Tribolium castaneum (Herbst). The diatomaceous earth, applied in concentrations of 0.5 g, 1 g and 2 g kg-1 rice, reduced numbers of surviving beetles significantly (over a period of 3 weeks). A single treatment with the neem product, in concentrations of 0.01 g, 0.1 g, 0.2 g and 1 g azadirachtin kg-1 rice, increased the mortality rate for both species significantly. The combination of neem and diatomaceous earth (1 g diatomaceous earth with 0.2 g or 1 g azadirachtin kg-1 rice) was more effective than the single treatment in reducing numbers of surviving beetles.  相似文献   

6.
The commercial available diatomaceous earth Fossil Shield® and the neem product Neem Azal-T/S® are tested as single treatments and in combination as controls for the stored product pests Sitophilus oryzae (L.) and Tribolium castaneum (Herbst). The diatomaceous earth, applied in concentrations of 0.5 g, 1 g and 2 g kg-1 rice, reduced numbers of surviving beetles significantly (over a period of 3 weeks). A single treatment with the neem product, in concentrations of 0.01 g, 0.1 g, 0.2 g and 1 g azadirachtin kg-1 rice, increased the mortality rate for both species significantly. The combination of neem and diatomaceous earth (1 g diatomaceous earth with 0.2 g or 1 g azadirachtin kg-1 rice) was more effective than the single treatment in reducing numbers of surviving beetles.  相似文献   

7.
Fusarium oxysporum and Fusarium proliferatum are important causal agents of crown and root rot of asparagus. In order to detect differences in pathogenicity and aggressiveness, two F. proliferatum and five F. oxysporum single spore isolates from asparagus spears from plantings in Austria and Germany, 55 pure cultures of F. oxysporum from asparagus roots from a planting in Hesse, Germany, and a single F. oxysporum isolate from an asparagus shoot collected in Austria were evaluated in a 28-day quick test on Hoagland??s agar in glass culture tubes. Plantlets were inoculated with spore suspensions from each respective isolate after 14 days of growth under sterile, controlled conditions in a growth chamber. A severity scale was used to assess symptoms on roots two weeks after inoculation. The effects of the single-spore isolates on root and shoot fresh weights of the plantlets were also determined. The pathogenicity of the majority of the F. proliferatum and F. oxysporum isolates included in this study was confirmed. Inoculation with pure and single-spore cultures resulted in elevated disease severity in comparison to non-inoculated controls. In particular, the two F. proliferatum isolates were found to be more aggressive than the F. oxysporum isolates. Moreover, all single spore isolates caused a reduction in fresh weight of roots and shoots in comparison to the controls. With respect to differences among asparagus cultivars, ??Ramos??, was found to be more susceptible than ??Ravel??. Overall, the quick test method was found to be capable of evaluating the pathogenicity and aggressiveness of the tested F. oxysporum and F. proliferatum isolates towards asparagus within 28 days.  相似文献   

8.
Zusammenfassung  In den Jahren 1992 und 1993 wurden 24 schwarzeTheysohn-Schlitzfallen mit Kombinationen von synthetischen Borkenk?ferlockstoffen, Pheroprax, Chalcoprax, Linoprax und Cembrax, auf ihre F?ngigkeit getestet. Zum Vergleich wurden Fallen mit Einzelbestückung und Zweifachkombinationen von Pheroprax+Cembrax und Linoprax+Cembrax sowie zwei Fallen ohne Lockstoff in einem 24 ha gro?en Forstgebiet aufgestellt. Mit den Fallen wurde die Flugaktivit?t der angelockten Scolytiden ermittelt. Die erhaltenen Fangzahlen vonIps typographus, Pityogenes chalcographys, Xyloterus lineatus undX. domesticus wurden w?chentlich registriert und in Verbindung mit der unterschiedlichen Pheromonbestückung der Fallen diskutiert. Von den drei letztgenannten Arten wurde der Fang von M?nnchen und Weibchen getrennt bewertet. In einzeln mit Pheroprax bestückten Fallen fanden sich die meisten Buchdrucker pro Falle. Ihr Anteil nahm 1993 um 9% gegenüber dem Vorjahr zu. Für den Kupferstecher waren die vierfach kombinierten Pheromonfallen etwas f?ngiger als die einzeln mit Chalcoprax bestückten Fallen. AuchXyloterus-Arten bevorzugten die vierfach kombinierten Pheromonfallen gegenüber solchen, die nur Linoprax enthielten. Die Anzahl der gefangenen Ambrosiak?fer wurde im Verlauf von 5 Jahren stark reduziert. In beiden Untersuchungsjahren wurden neben den gezielt gek?derten Scolytiden 252 K?ferarten aus 49 Familien registriert, von denen 10 Arten eine Pheromonpr?ferenz erkennen lie?en. Der Beifang betrug j?hrlich 0,6–0,7% der Gesamtzahl an gefangenen K?fern. Zu 85–87% war der Kupferstecher am Gesamtfang beteiligt. Der Buchdrucker hatte einen Anteil von 11–14% an der Gesamtausbeute.
In the years 1992 and 1993 blackTheysohn slit-traps were set up in a forest area near Hanover, Germany. The traps were baited with combinations of the synthetic bark beetle pheromones Pheroprax?, Chalcoprax?, Linoprax?, and Cembrax?. Their captivity was tested in comparison to singly baited and control traps without pheromone. Additionally, combinations of Pheroprax+Cembrax and Linoprax+Cembrax were tested. The captivity numbers obtained fromIps typographus, Pityogenes chalcographus, Xyloterus lineatus andX. domesticus were discussed in relation to the differently baited traps. In the latter three species, females and males were separated. The periods of flight activity of the four Scolytidae baited were ascertained for both years. Concerning the singly baited traps, Pheroprax captured the highest amount ofIps typographus per trap, its population increased 9% in 1993 related to that of 1992. ForP. chalcographus, the combination of the four pheromones resulted in a little higher number of individuals than in singly baited traps.Xyloterus lineatus preferred the four-pheromone combination, in which Linoprax was present showing a synergistic effect of baiting. In contrary, the baiting ofX. domesticus was lower by the combined pheromones than by Linoprax alone. The latter was found in lower numbers thanX. lineatus. The trapped amounts of both Xyloterus species were continuously reduced throughout the years 1989 to 1993. The Coleoptera species, not specially trapped, amounted yearly to 0.6–0.7% of the collected individuals.P. chalcographus was collected to 85–87%, andIps typographus to 11–14% of the total amount of Coleoptera trapped.
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9.
In den Jahren 1992 und 1993 wurden 24 schwarzeTheysohn-Schlitzfallen mit Kombinationen von synthetischen Borkenk?ferlockstoffen, Pheroprax, Chalcoprax, Linoprax und Cembrax, auf ihre F?ngigkeit getestet. Zum Vergleich wurden Fallen mit Einzelbestückung und Zweifachkombinationen von Pheroprax+Cembrax und Linoprax+Cembrax sowie zwei Fallen ohne Lockstoff in einem 24 ha gro?en Forstgebiet aufgestellt. Mit den Fallen wurde die Flugaktivit?t der angelockten Scolytiden ermittelt. Die erhaltenen Fangzahlen vonIps typographus, Pityogenes chalcographys, Xyloterus lineatus undX. domesticus wurden w?chentlich registriert und in Verbindung mit der unterschiedlichen Pheromonbestückung der Fallen diskutiert. Von den drei letztgenannten Arten wurde der Fang von M?nnchen und Weibchen getrennt bewertet. In einzeln mit Pheroprax bestückten Fallen fanden sich die meisten Buchdrucker pro Falle. Ihr Anteil nahm 1993 um 9% gegenüber dem Vorjahr zu. Für den Kupferstecher waren die vierfach kombinierten Pheromonfallen etwas f?ngiger als die einzeln mit Chalcoprax bestückten Fallen. AuchXyloterus-Arten bevorzugten die vierfach kombinierten Pheromonfallen gegenüber solchen, die nur Linoprax enthielten. Die Anzahl der gefangenen Ambrosiak?fer wurde im Verlauf von 5 Jahren stark reduziert.  相似文献   

10.
Between 2005 and 2007 a total of 1364 oilseed rape (OSR) fields in 12 federal states of Germany was surveyed. Investigations took place in late autumn and included the identification and counting of all weeds in unsprayed parts of rape fields. Results on the impact of tillage intensity and crop sowing date on the level of total weed infestation, weed species number and weed flora composition in OSR fields are shown and those species identified which are sensitive to the analysed factors. Neither tillage intensity nor crop sowing date affect the level of weed infestation in OSR fields. In contrast, species richness was enhanced by non-inversion tillage as well as by an early crop sowing. While there were statistically proofed differences in the weed species composition of ploughed and unploughed OSR fields due to canonical correspondence analysis, the crop sowing date only had minor effects on species composition. Nevertheless, a multitude of single weed species was affected by tillage intensity and sowing date showing significantly differing relative frequencies and/or densities in fields with inversion and non-inversion tillage as well as between early and late sown crop. Among others Centaurea cyanus, Anchusa arvensis, A. spica-venti and Elymus repens were more abundant and partly reached higher densities after ploughing, whereas non-inversion tillage mainly favoured Galium aparine, Geranium spp. and Sisymbrium spp.. Lots of weed species tended to have higher populations when OSR was sown before August 15th, species significantly increased by early sowing date were e. g. Centaurea cyanus, Convolvulus arvensis, Euphorbia spp. and Anchusa arvensis. However, only V. arvensis reached significantly higher densities when OSR was sown after September 1st.  相似文献   

11.
The Institute for Strategies and Technology Assessment of the Julius Kühn-Institute operates four different networks: demonstration farms on IPM, reference farms for plant protection, panel pesticide applications and NEPTUN farms. All networks deal with the use of plant protection products in agricultural practice. The latter three also have very similar tasks and are closely interlinked. As a result, outsiders have significant problems distinguishing between those four farm networks and assigning the respective activities to the “right” corresponding network.Therefore, the publication aims at presenting comparatively the tasks and objectives of the various networks and to explain to the reader what are they doing, what are the differences, as well as why and how the establishment of these four different farm networks has come about.  相似文献   

12.
Maize production trials carried out in eastern middle of Germany from 1999–2007 were used for statistical analysis of the optimum date for silage maize ripeness, quality and yield potential as well as choice of cultivar under drought conditions for silage and energy maize. The Silage maize Ripeness Index (the ratio of dry matter content of maize grains to dry matter content of stover) is more suitable for the determination of harvest date, yield maximum and silage maize quality as the dry matter content of the plant. The analysis is cheaper as well as not so material and time-consuming in comparison to the dry matter content of the silage maize of different hybrid maize populations and environments. Ensilage optimum and yield maximum correspond almost with the physiological ripeness of silage maize and are close to the grain dry matter content of 60 to 65%, to the dry matter content of stover under 24% and a ripeness index from 2,5 and higher. Only under these conditions it is possible to reach the optimal ripeness of 30 to 35% in the whole plant silage maize. In dependence on the Silage maize Ripeness Index (SRZ) parameters of silage and energy maize were created differential ripeness optimum, quality and yield potential. The aims of silage and energy maize are similar. The vitality of stover has a greater importance for energy maize. The Silage maize Ripeness Index (SRI) is, for whole plant maize, better than the Whole Plant Maize Ripeness Index (SRZ) for the choice of a hybrid in Germany. The dry matter content of grain in interaction with the dry matter of stover are better than dry matter content of the whole plant maize as ripeness indicator in the production of silage and energy maize for the harvesting time. SRI is also suitable for use as a standard in scientific trials and for better characteristic of cultivar types and environmental influence.  相似文献   

13.
Cover crops and under-sown crops have often been reported to have a positive impact on soil structure, soil living organisms and soil fertility. In many studies it was shown that they suppress weed populations. However, the percentage of winter annual cereals in European cropping system has strongly increased, which consequently reduced the time for growing cover crops. In this study, it was investigated if cover crops and under-sown have the capacity to reduce weed infestations also in rotations with a high percentage of winter annual cereals. Three field trials were conducted using at the University of Hohenheim from 2008 until 2010. Trifolium repens and Lolium perenne reduced weed density and weed biomass in Triticum aestivum and Triticum spelta, when they were sown as under-sown crops. Both under-sown crops had no negative effect on grain yield. Until 14 days after harvest, the under-sown crops developed a dense plant canopy. In the third experiment, Sinapis alba, Phacelia tanacetifolia, Avena strigosa and a mixture of Trifolium alexandrinum, Vicia sativa, Fagopyrum tataricum and Guizotia abyssinica were sown directly after harvest of winter wheat. Most of the cover crops emerged after few days and significantly reduced the density and biomass of emerging weeds. Sinapis alba resulted in a 93% reduction of above-ground weed biomass. Avena strigosa reduced root-biomass of weed by 97% and weed density by 90%. In order to achieve a significant weed suppression, cover crops need to emerged quickly and grow rapidly until the soil has been covered. The results of this study underline the potential of under-sown crops and cover-crops to support a sustainable and environmental friendly cropping system.  相似文献   

14.
One year old rooted cuttings were fertilized with Osmocote exact according to 0,8 g N L? ? 1 substrate in February 2009. In August half of the plants received the same fertilizer dose while the other half was not refertilized. In autumn 2009 and in spring 2010 early resp. late frost tests were carried out under controlled conditions, furthermore sprouting was evaluated in spring 2010. Frost damage was measured with the electrolyte leakage method. In the early frost test biochemical stress responses like glucose, sucrose and proline were analyzed. In the new shoots N-, P-, and K-concentration were measured. Refertilized plants did not grow more but showed higher N-, P-, and K-concentrations. These plants had more proline in their buds and roots compared to the non-refertilized ones. Sucrose and glucose contents in the roots of refertilized plants were lower than in non-refertilized ones, in the buds there was no difference. Damage due to early frost was independent from refertilization for new shoots and buds but in roots higher for the refertilized plants. In spring 2010 refertilized plants sprouted earlier compared to non-refertilized ones. In buds damage due to late frost slightly increased in refertilized plants while in roots there was no difference between the fertilization treatments.  相似文献   

15.
Monitoring of the pathogen spectrum in grain peas (Pisum sativum L.) was conducted in Germany between 2005 and 2007. The outcome of this study implies that the infections of pathogens depend on the annual weather condition and the geographic area.Ascochyta pinodes, which infects aerial plant organs, was the pathogen found most frequently (on average 61, 8%). Especially in years with moist weather conditions a more severe spreading of the pathogen could be observed. Similarly, the occurrence ofBotrytis cinerea depends on the weather conditions. In 2007 were optimal conditions for infections and consequentlyB. cinerea was found with a high frequency of about 70%. Regarding diseases on root and stem base, this study clearly shows that infection of less prominent Fusarium species, such asF. redolens andF. avenaceum was significantly higher compared toF. oxysporum andF. solani.  相似文献   

16.
Wheat insect pests and the beneficial arthropod populations were assessed using sweep net across a large scale winter wheat field in Bad Lausick (Free State of Saxony, Germany) before and after insecticide applications. The insecticides used were Karate (pyrethroid), Biscaya (neonicotinoid) and NeemAzal T/S (botanical insecticide). The tested compounds were sprayed twice during the early season growth stage (Elongation- GS 32) and at the heading stage (GS 55), and their effects were evaluated on wheat insect pests. The side effects of these insecticides on associated natural enemies were also studied. Monitoring was conducted for 4 weeks after each treatment. Cereal aphids, thrips, leafhoppers, cereal leaf beetles, cereal bugs and also many natural enemies such as predators (lady beetles, lacewings, syrphids, dance flies and spiders) and parasitoids (parasitic wasps) were surveyed. The dose of these insecticides resulted in reductions of wheat insect and natural enemy populations and this reduction was corrected based on Abbott equation. The results showed that Karate is correlated with the highest percentage reduction (79.5 %) to wheat insect pests. Karate use also resulted in a percentage reduction to natural enemies (30–60 %). Biscaya and NeemAzal T/S is correlated with an equivalent mortality percents (50–65 %) to wheat insect pests and resulted in a smaller percentage reduction of natural enemies (10–40 %) compared to Karate. Thrips and cereal bugs were more affected than leafhoppers. Lacewings and dance flies were more susceptible; while spider, syrphids and parasitoid wasps were more tolerant. Compatibility between natural insecticides and natural enemies is highly required to keep the environment clean.  相似文献   

17.
Abstract In the frame of the investigation of epidemiology of soil-borne viruses, like the Soil-borne cereal mosaic virus (SBCMV), Soil-borne wheat mosaic virus (SBWMV) and the Bymovirus Wheat spindle streak mosaic virus (WSSMV), which were transmitted by fungal vector Polymyxa graminis Ledingham, the infection progress in different cereals was observed. The detection of furovirus and bymovirus in field plants was depending on temperature conditions during the vegetation period and the kind of cereals. The furoviruses tolerate a broad temperature spectrum and once established infection is detectable until the harvest time. In contrast to this observation, the propagation of WSSMV seems to be restricted to lower temperatures. Consequently, this virus is detected best at the end of February until the middle of April. Among the tested cereals, rye becomes more early infected than wheat and triticale. Both furoviruses could be differed by variable virulence reactions on cereal hosts and indicator plants. The SBCMV infects rye, triticale and wheat but not barley. The SBWMV is able to contaminate beside these cultures barley too. Both viruses are distinguished in the infection typ in Nicotiana benthamiana. Whereas SBCMV isolates spread out in the whole plant and cause yellowing and the die back of plants, the SBWMV infects the inoculated leaves only.  相似文献   

18.
Mountains are currently less affected by plant invasions than lowland ecosystems. Since 2005 the Mountain Invasion Research Network (MIREN, www.miren.ethz.ch) investigates the risk of plant invasions into mountains and develops preventive management strategies. A database of non-native and invasive plant species in mountains worldwide includes currently some 1500 species. Particularly problematic are woody species and ornamental plants that are often pre-adapted to a mountain climate. The risk of plant invasions in mountains is expected to increase in the near future. Climate change will enable the upward movement of lowland invaders into mountain ecosystems. Increased anthropogenic land use and disturbances and a shift of land use from grazing systems to tourism, which will lead to the introduction of new non-native plants, may further increase invasion risks. Mountains, and in particular the European Alps, are among the very few ecoregions in the world not yet badly affected by plant invasions. Managers have the unique opportunity to respond in time to an emerging threat. Preventive measures are the most effective and cost-efficient management option. Regulation of the transport of potentially invasive plant species should be a management priority. With climate change the upward movement of native lowland plants may also become a conservation concern. A broad discussion of the valuation and management of the change of mountain floras is needed. Besides plants other groups of organisms such as animal and plant pests may increasingly become a problem in mountains.  相似文献   

19.
Here we reviewed the possible impacts of weather extremes on pests (weeds, insect pests and plant pathogens) of wine, hope, apple and asparagus by analyzing scientific literature published since 1945, concerning the knowledge about the influences of extreme weather on incidence of these pests. A weather extreme event is generally defined as the occurrence of a value of a weather variable above or below a threshold value near the upper or lower tails of the range of observed values of the variable (IPCC). Although there are still many open scientific questions, climate change will likely lead to increase the frequency, intensity, spatial extent, duration and timing of weather and climate extremes and can result in unprecedented extremes. After considering all the results of derivative analysis, we concluded that the knowledge gap is enormously. Only 13 papers were found. These few papers concerning the influence of storm, hail, flooding, dryness or heavy down pours on the pests of apple (10 papers), asparagus (2 papers) or wine (1 paper). Thus projections of future impacts of extreme weather on plant pests and yields cannot be made with a high level of confidence. More research to get more primary results and data is needed urgently.  相似文献   

20.
Peruvian nutritional indicators demonstrate, in particular for the underprivileged groups in remote regions, as in Iquitos, a malnutrition caused by the insufficient uptake of vitamins and mineral nutrients. Promoting cultivation and consumption of vegetables shall counteract this situation, but unfavourable tropical conditions complicate local crop growing in Iquitos. Due to transportation by air, in Iquitos imported vegetables are expensive goods and thereby prohibitive for many people. Soilless cultivation techniques represent an opportunity to cultivate high-value crops throughout the year on a regional basis. By the use of simplified methods, this technique also offers the underprivileged population the means to provide themselves with healthy vegetables. In the present study, regional available cultivation media were tested for simplified soilless cultivation in Iquitos. The characteristics of one substrate-less cultivation method based on a nutrient solution and eight different types of substrates, derived from the base substrates rice husks, gravel, sand and composted saw dust were compared. Using the example of Lactuca sativa L. var. crispa L. ??Grand Rapids??, general and physico-chemical characteristics of the nine cultivation media and their influence on crop developing and crop quality were determined. Results show that rice husks also gravel-sand-mix 2:1 and 1:2 are particularly suitable for soilless cultivation of loose leaf lettuce in Iquitos. Using these substrates, lettuce showed the best growth of shoots and roots and the highest yield. The crop quality was high for all tested cultivation media. If high weight and cost of the mineral substrate is not assessed negatively, it could also be used for plant breeding. It is to be assumed that a combination of rice husks and gravel-sand-mix is advantageous, since an optimised substrate weight and an improved water-air balance are to be expected.  相似文献   

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