Browsing by Person "Aufhammer, Walter"

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Ertragsbildung und Konkurrenzverhalten perennierender Körnerfruchtarten in Rein- und Mischbeständen auf marginalen Standorten
(2002) Weik, Lena; Aufhammer, Walter
Cultivation of perennial grain crops in pure and mixed stands was examined as a possibility for preserving marginal arable land. The following questions were investigated: - Which dry matter and grain yield potential do these species display on marginal lands? - Are the examined species able to persist on marginal sites? - Can effects of competition be identified in mixed stands of perennial grain crops by commonly used static and dynamic parameters? - Which competitiveness do the examined species show in mixed stands compared to pure stands? In field experiments perennial species of rye (Secale cereale x S. montanum), intermediate wheatgrass (Elymus hispidus), lupine (Lupinus polyphyllus) and linseed (Linum perenne) were grown in pure and different mixed stands. Intermediate wheatgrass reached with a maximum at almost 13 t ha-1 highest dry matter yields. Grain yields were on a low level, maximum yields were obtained with 2.7 t ha-1 in pure stands of rye. Intermediate wheatgrass and lupine demonstrated the best ability for perennialism. Rye showed a satisfactory ability to persist only when grown in mixture with legumes. The persistence of linseed was very low. The relative yield total (RYT) was found to be a suitable static indicator of resource complementarity. Competitive ability was appropriately described by the competitive balance index (Cb). Regression models derived from Lotka-Volterra equations rendered a good description of dynamic growth and competition. Both grass species were in most cases stronger competitors than the companion species. The experiments showed, that using grain cop mixtures of grasses and legumes seem to be most promising for cultivation on marginal lands.
Management of Fusarium graminearum-inoculated crop residues : effects on head blight, grain yield and grain quality of subsequent winter wheat crops
(2001) Yi, Cuilin; Aufhammer, Walter
On the experimental station Ihinger Hof of Hohenheim University field experiments with artificial inoculation were conducted. An isolation-strip experiment included strips of winter rape crops, separating non-inoculated test plots of wheat from inoculated wheat plots. For the main field experiment, maize or spring wheat were planted as pre-crops in rotations with winter wheat and different crop residue treatments were applied. Additional residue management greenhouse tests were conducted and treated equivalent to the field experiment. Results of isolation-strips field experiments with wheat showed that. Isolation strips of 2 m width reduced disease incidence on neighbour plots by more than 50%. A further increase in isolation strip width did improve the isolation effect, but the differences between isolation strip widths were comparatively small. The infection in test plots was not completely eliminated even with 8 m wide strips. Greenhouse tests of residue management showed that deeper residue incorporation effectively reduced the F. g. populations on residues. The application of nitrolime reduced the population level of F. g. On the contrary, fertilization with calcium ammonium nitrate promoted F. g. populations. Soaking the residues in a fungicide preparation eliminated F. g. on the residues completely. Residue management field experiments with artificial inoculation of pre-crops, there were no significant differences in infection level after either maize or wheat, and the infection level of winter wheat was especially high after maize for silage use in one year. The reductions of FHB incidence due to ploughing or nitrolime application were 27-32% or 31-59% compared with residues remaining on the surface or calcium ammonium nitrate fertilization, respectively. But at that moderate FHB infection level, the residue management hardly influenced wheat grain yield and technological grain quality.
Optimierung und Bewertung der Produktion von Getreidekorngut als Rohstoff für die Bioethanolerzeugung
(2001) Rosenberger, Alexander; Aufhammer, Walter
Varied cultivation of high yielding winter cereals to be used as bioethanol grains were examined regarding agronomic and fermentation traits as well as with respect to energetic, economic and environmental aspects. Empirical data were taken from biennial factorial field trials with winter cereals at two different experimental sites of Hohenheim University. These are the central conclusions: A-state-of-the-art conversion process presupposed, the cultivation of high-yielding cereals in crop rotations including previous legume crops is an energetically and economically efficient option to optimize the production of bioethanol grain and hence of bioethanol. From the ecologic view, crop production aligned to high grain yields is conflicting with respect to the enhancement of fossil primary energy conservation and thus the avoidance of greenhouse gas emissions relative to the reference fossil fuel and incremental releases of other ecologically relevant substances as compared to low-input crop management.