Poorly crystalline iron and aluminium oxides contribute to the carbon saturation and sorption of dissolved organic carbon in the soil     

Tania Khandakar  Chris Guppy  Sheikh M. F. Rabbi  Heiko Daniel 《Soil Use and Management》2021,37(1):120-125

Soil carbon (C) saturation implies an upper limit to a soil's capacity to store C depending on the contents of silt + clay and poorly crystalline Fe and Al oxides. We hypothesized that the poorly crystalline Fe and Al oxides in silt + clay fraction increased the C saturation and thus reduced the capacity of the soil to sorb additional C input. To test the hypothesis, we studied the sorption of dissolved organic carbon (DOC) on silt + clay fractions (<53 µm) of highly weathered oxic soils, collected from three different land uses (i.e., improved pasture, cropping and forest). Soils with high carbon saturation desorbed 38% more C than soils with low C saturation upon addition of DOC, whereas adsorption of DOC was only observed at higher concentration (>15 g kg^?1). While high Al oxide concentration significantly increased both the saturation and desorption of DOC, the high Fe oxide concentration significantly increased the desorption of DOC, supporting the proposition that both oxides have influence on the DOC sorption in soil. Our findings provide a new insight into the chemical control of stabilization and destabilization of DOC in soil.  相似文献   

Genetic diversity of Sudanese pearl millet (Pennisetum glaucum (L.) R. Br.) landraces as revealed by SSR markers,and relationship between genetic and agro-morphological diversity     

Elfadil M. A. Bashir  Abdelbagi M. Ali  Adam M. Ali  El Tahir I. Mohamed  Albrecht E. Melchinger  Heiko K. Parzies  Bettina I. G. Haussmann 《Genetic Resources and Crop Evolution》2015,62(4):579-591

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The use of lysimeter data for the test of two soil–water balance models: A case study     

Martin Wegehenkel  Yongqian Zhang  Thomas Zenker  Heiko Diestel 《植物养料与土壤学杂志》2008,171(5):762-776

Two soil–water balance models were tested by a comparison of simulated with measured daily rates of actual evapotranspiration, soil water storage, groundwater recharge, and capillary rise. These rates were obtained from twelve weighable lysimeters with three different soils and two different lower boundary conditions for the time period from January 1, 1996 to December 31, 1998. In that period, grass vegetation was grown on all lysimeters. These lysimeters are located in Berlin‐Dahlem, Germany. One model calculated the soil water balance using the Richards equation. The other one used a capacitance approach. Both models used the same modified Penman formula for the estimation of potential evapotranspiration and the same simple empirical vegetation model for the calculation of transpiration, interception, and evaporation. The comparisons of simulated with measured model outputs were analyzed using the modeling‐efficiency index IA and the root mean squared error RMSE. At some lysimeters, the uncalibrated application of both models led to an underestimation of cumulative and annual rates of groundwater recharge and capillary rise, despite a good simulation quality in terms of IA and RMSE. A calibration of soil‐hydraulic and vegetation parameters such as maximum rooting depth resulted in a better fit between simulated and observed cumulative and annual rates of groundwater recharge and capillary rise, but in some cases also decreased the simulation quality of both models in terms of IA and RMSE. The results of this calibration indicated that, in addition to a precise determination of the soil water‐retention functions, vegetation parameters such as rooting depth should also be observed. Without such information, the rooting depth is a calibration parameter. However, in some cases, the uncalibrated application of both models also led to an acceptable fit between measured and simulated model outputs.  相似文献   

Simulation of snowmelt erosion using the EROSION 3D model     

Astrid Weigert  Gerald Wenk  Gregor Ollesch  Heiko Fritz 《植物养料与土壤学杂志》2003,166(1):128-130

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Geographic Pattern of Genetic Diversity Among 43 Ethiopian Mustard(Brassica carinata A. Braun) Accessions as Revealed by RAPD Analysis     

Adefris Teklewold  Heiko C. Becker 《Genetic Resources and Crop Evolution》2006,53(6):1173-1185

As an oilseed crop, the cultivation of Ethiopian mustard (Brassica carinata) is restricted only to Ethiopia. Even though geographic diversity is a potent source of allelic diversity, the extent of genetic diversity among germplasm material of Ethiopian mustard from different countries has not been assessed. Forty-three accessions, comprising 29 accessions from eight different geographic regions of Ethiopia and 14 exotic accessions from Australia, Pakistan, Spain, and Zambia were analysed for their genetic diversity using random amplified polymorphic DNA (RAPD) technique. A set of 50 primers yielded a total of 275 polymorphic bands allowing an unequivocal separation of every Ethiopian mustard accession. The usefulness of the 50 RAPD primers in measuring heterozygousity and distinguishing accessions was variable such that polymorphic information content (PIC) varied from 0.05 to 0.40, band informativeness (BI) from 0.05 to 0.65 and primer resolving power (RP) from 0.15 to 6.83. Jaccard's similarity coefficients ranged from 0.44 to 0.87 indicating the presence of a high level of genetic diversity. On the average, Australian and Ethiopian accessions were the most similar while, Spanish and Zambian accessions were the most distant ones. Cluster analysis grouped the 43 accessions into four groups, which has quite a high fit (r = 0.80) to the original similarity matrix. With no prior molecular information, the RAPD technique detected large genetic diversity among the 43 accessions from five different countries and their grouping by dendrogram and principal coordinate analysis (PCoA) was inclined towards geographic differentiation of RAPD markers. Conversely, RAPD differentiation along geographic origin was not apparent within the Ethiopian accessions.  相似文献   

Selection for <Emphasis Type="Italic">Phytophthora</Emphasis> field resistance in the F<Subscript>2</Subscript> generation of organic outdoor tomatoes     

Bernd Horneburg  Heiko C. Becker 《Euphytica》2011,180(3):357-367

Tomatoes are the most important vegetable, globally as well as in Germany. Outdoor tomato production is seriously impaired due to increasing infections with evolving late blight (Phytophthora infestans) populations. Within organic agriculture, research is being conducted to develop regionally adapted and open pollinated cultivars of outdoor tomatoes with late blight field resistance. In the present experiment, three crosses, including wild, cocktail, and beefsteak tomatoes, were selected for field resistance against late blight in F₂ at one location per cross. The comparison of positive and negative selection in F₃ revealed the selection of single F₂ plants to be efficient in all three crosses. F₂ selection has proved to be a robust and efficient tool for breeding programs. The correlated response to selection in other traits, including yield, fruit weight, days to maturity, harvest period, and plant height, depended on the cross. It was evident that selection for desired traits combined with field resistance against late blight is promising, even in wide crosses. The most undesired attribute of wild tomatoes is the formation of shoots on leaves and in inflorescences. No correlation was observed between field resistance and shoot formation, allowing the selection of genotypes with improved field resistance and yield, but without morphological disadvantages.  相似文献   

Diversity in genetic structure and chemotype composition of <Emphasis Type="Italic">Fusarium graminearum</Emphasis> sensu stricto populations causing wheat head blight in individual fields in Germany     

Firas Talas  Heiko K. Parzies  Thomas Miedaner 《European journal of plant pathology / European Foundation for Plant Pathology》2011,131(1):39-48

Fusarium head blight (FHB) is one of the most destructive diseases of wheat. Twelve small commercial wheat fields (size 1–3 hectares) were sampled in Germany for Fusarium populations at three spots per field with 10 heads each. PCR assays using generic primers confirmed 338 isolates as F.graminearum sensu stricto (s.s.) (64.9%) out of 521 Fusarium spp. that were further analyzed. Populations of F. graminearum s.s. in Germany contain three types of trichothecenes with a dominancy of 15-acetyldeoxynivalenol chemotype (92%) followed by 3-acetyldeoxynivalenol chemotype (6.8%) and a few isolates of nivalenol chemotype (1.2%). All these isolates were genotyped using 19 microsatellite loci. The 12 populations showed a high genetic diversity within the small scale sampling areas resulting in 300 different haplotypes. Genetic diversity within populations (71.2%) was considerably higher than among populations (28.8%) as shown by analysis of molecular variance. Gene flow (Nm) between populations ranged from 0.76–3.16. Composition of haplotypes of one population followed over 2 years changed considerably. No correlation between genetic and geographical distance was found. In conclusion, populations of F. graminearum s.s. in Germany display a tremendous genetic variation on a local scale with a restricted diversity among populations.  相似文献   

SURVIS: a fully-automated aerial baiting system for the distribution of vaccine baits for wildlife     

Müller T  Freuling CM  Gschwendner P  Holzhofer E  Mürke H  Rüdiger H  Schuster P  Klöss D  Staubach C  Teske K  Vos A 《Berliner und Münchener tier?rztliche Wochenschrift》2012,125(5-6):197-202

Large-scale oral vaccination of wildlife against rabies using aerial bait distribution has been successfully used to control terrestrial wildlife rabies in Europe and North America. A technical milestone to large-scale oral rabies vaccination campaigns in Europe was the development of fully-automated, computer-supported and cost-efficient technology for aerial distribution of baits like the SURVIS -system. Each bait released is recorded by the control unit through a sensor, with the exact location, time and date of release and subsequently the collected data can be evaluated, e.g. in GIS programmes. Thus, bait delivery systems like SURVIS are an important management tool for flight services and the responsible authorities for the optimization and evaluation of oral vaccination campaigns of wildlife against rabies or the control of other relevant wildlife diseases targeted by oral baits.  相似文献   

Diversity, distribution and management of yam landraces (Dioscorea spp.) in Southern Ethiopia     

Muluneh Tamiru  Heiko C. Becker  Brigitte L. Maass 《Genetic Resources and Crop Evolution》2008,55(1):115-131

Yam (Dioscorea spp.) is widely grown in many parts of Ethiopia and plays a vital role in local subsistence. Nevertheless, its diversity has not been studied in detail. A survey covering 339 farm households and eight districts was conducted in the major yam growing regions of Southern Ethiopia to investigate the diversity and distribution of yam landraces using structured and semi-structured questionnaires. A total of 37 named landraces were recorded, with a range from one to six (mean 2.9) on individual farms. Farmers’ decisions regarding the number and type of landraces maintained was influenced by tolerance of the landraces to drought, their maturity time and market demand. Most landraces had limited abundance and distribution, and only a few dominant landraces were widely grown. There was also variation amongst districts with respect to diversity, distribution and abundance of the landraces found. In the majority of the localities surveyed, farmers reported a decreasing trend in the number of landraces maintained on individual farms and in the overall yam production. Besides, in those limited areas where yam production is expanding, farmers are increasingly relying on a few selected landraces that mature early. Findings of this study suggest that local farmers in Wolayita and Gamo-Gofa zones maintain considerable yam diversity that remains to be further explored for sustainable utilization and conservation of the available genetic resources.  相似文献   

Bioindikatoren für den Dormanzstatus bei Obstgehölzen     

Laura Hillmann  Heiko Kaufmann  Michael Blanke 《Erwerbs-Obstbau》2016,58(3):141-157

This contribution is part of a bachelor thesis, which reviews the literature about suitable bio-indicators for the current dormancy status of a (fruit) tree in the winter. This is part of an on-going chilling research project and evaluation of the three chilling models as to their suitability for fruit growing in temperate zone regions with cool winters. The aim is to provide information on the dormancy status of a tree for the application of cultivation techniques to overcome dormancy.  相似文献