Die Wirkung von mikroskopischen Bodenpilzen auf den Trockensubstanzertrag von Hafer im Jugendwachstum     

Georg Müller  Harry Winkler 《Archives of Agronomy and Soil Science》2013,59(1-3):165-178

  相似文献   

Zur Kenntnis der Keimlingserkrankungen bei Koniferen     

Privatdozent Dr. Georg Funk 《European Journal of Forest Research》1922,44(10):381-388

  相似文献   

Bücheranzeigen     

Dr. Georg Henner  Tubeuf  Y.  Schüpfer  Dr. Dr. Ing. Fr. Moll 《European Journal of Forest Research》1928,50(11):374-384

  相似文献   

Bücheranzeigen     

Dr. Georg Henner 《European Journal of Forest Research》1927,49(20):742-743

  相似文献   

Methods for assessing regeneration establishment and height growth in uneven-aged mixed species stands     

Hasenauer  Hubert; Kindermann  Georg 《Forestry》2002,75(4):385-394

  相似文献   

Tree Planting by Smallholder Farmers in the Upper Catchment of Lake Tana Watershed,Northwest Ethiopia     

Abrham Abiyu  Demel Teketay  Georg Gratzer  Maru Shete 《Small-Scale Forestry》2016,15(2):199-212

Tree growing by smallholder farmers is an emerging livelihood strategy in Lake Tana catchment. The objectives of this study were to (1) identify the most important tree species grown, (2) investigate the drivers of the existing pattern, and (3) identify determinants of the number and diversity of tree species and their spatial patterns. Survey data were collected from 200 households. Multiple linear regression was employed to identify the determinants of tree growing behaviour of households and spatial variables affecting the abundance of tree species. Eucalyptus globulus, Acacia decurrens and E. camaldulensis dominate woodlots. Only a fraction of the forest production is used by the households, the rest being sold as poles or charcoal. Location in relation to market centres, number of livestock owned, landholding size and age of household head were found to positively affected the number of tree species and trees grown. Gender affected the species and spatial pattern of trees. Woodlots, farm boundaries and homesteads were found to be important tree growing niches. These results substantiate the proposition that farmers assign their parcels of land to uses that increase the rent value of the land, and this value is affected by access to roads. Woodlots are on the increase at the cost of productive agricultural land. Provision of a tree planting extension service may increase participation of farmers in tree planting, and a management-oriented tree planting extension service may give desirable results.  相似文献   

Implications of heterogeneity on procedures for estimating plant 15N recovery in hedgerow intercrop systems   总被引：2，自引：0，他引：2  

E. C. Rowe  G. Cadisch 《Agroforestry Systems》2002,54(1):61-70

Nitrogen flows in agroforestry systems can be quantified by applying excess ¹⁵N to one pool or part of the system and subsequentlymeasuring the quantity of ¹⁵N in other pools. Accurate quantifications depend on accurate determination of the mass, percentage N, and percentage ¹⁵N enrichment of each pool and past studies have mainly used physically isolated subplots to reduce variability. We thus assessed the within-plot and within-plant variability of ¹⁵N recovery by maize and by two hedgerow tree species, Gliricidia sepium and Peltophorum dasyrrachis, following applications of ¹⁵N-enriched materials to unbounded plots. We also assessed the potential for estimating total plant ¹⁵N recovery from a reduced set of samples, and for estimating N content allometrically from simple measurements. ¹⁵N uptake beyond 1 m radius was negligible in maize but recommended minimum inter-plot spacing for Gliricidia sepium and Peltophorum dasyrrachis was 8 m. Within-plant variation was also greater in trees than in maize. Calculating recovery from all crop plant components is not always necessary; the recovery of ¹⁵N in maize grain predicted 98.9% of variation in total plant ¹⁵N recovery. 89–95% accurate estimates of biomass and N content of maize plants and of regrowing tree shoots can be obtained non-destructively from height or basal shoot diameter respectively. ¹⁵N tracing techniques are potentially very useful for studies of competition and complementarity with respect to nitrogen uptake in agroforestry systems but they require unbounded plots and hence particular care in design and sampling procedures. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

Applied physics. High-speed atomic force microscopy     

Hansma PK  Schitter G  Fantner GE  Prater C 《Science (New York, N.Y.)》2006,314(5799):601-602

  相似文献   

Comparison of binding and effects of Escherichia coli Shiga toxin 1 on bovine and ovine granulocytes     

Menge C  Eisenberg T  Stamm I  Baljer G 《Veterinary immunology and immunopathology》2006,113(3-4):392-403

Granulocytes play a pivotal role in the pathogenesis of Shiga toxin (Stx)-producing Escherichia coli (STEC) related diseases in humans. Granulocytes are attracted and activated by Stxs in the enteric mucosa and are believed to thereby contribute to the intestinal inflammation. Mature ruminants, the main reservoir hosts of STEC, do not develop pathological changes that can be attributed to the Stxs. To prove whether the latter phenomenon correlates with the inability of the Stxs to affect granulocytes of ruminants, we investigated the ability of Stx1 to bind to granulocytes of cattle and sheep and analysed the effects of Stx1 on viability, phagocytosis, and oxidative burst activity. Bovine granulocytes from blood and milk did not express Stx1-binding sites even after activation of the cells and also were resistant to Stx1. In contrast to bovine granulocytes, granulocytes of sheep constitutively expressed Stx1-receptors of the Gb(3)/CD77 type ex vivo and bound the recombinant B-subunit of Stx1 (rStxB1). Stx1 holotoxin induced apoptosis in ovine granulocytes after prolonged incubation (18h) but Stx1 only slightly altered the phagocytosis and oxidative burst activities. The rStxB1 had no effect on granulocytes of either species. While arguing in favour of our initial hypothesis, that granulocytes of both, cattle and sheep are not activated by Stxs, the results of our study are the first evidences for differences in the cellular distribution of Stx-receptors in species equally regarded as STEC carriers.  相似文献   

Acknowledgements to referees     

Asko Mäki‐Tanila  Georg Erhardt  Ignacy Misztal  Larry Schaeffer  Henner Simianer  Julius Van Der Werf 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2009,126(6):492-492

  相似文献