title: Biomass production and nitrogen content of C3- and C4- grasses in pure and mixed culture with different nitrogen supply.
abstract: Two C3grasses (Hordeum vulgare L., Avena sativa L.) and two C4grasses (Panicum miliaceum L., Panicum crus-galli L.) were cultivated in standard soil in the open air in pure cultures and in various mixed cultures at low and high nitrogen fertilization levels. After three months the dry weight, length and nitrogen content of the aboveground and below-ground parts of the plants and the shoot/root ratios were determined. Hordeum vulgare was the most successful species irrespective of the nitrogen fertilization level, and also exhibited in most cases the highest nitrogen concentrations. Panicum miliaceum, on the other hand, was the species least able to compete. The production of biomass was reduced in cultures growing under nitrogen starvation conditions, this phenomenon being more pronounced with respect to the C4than to the C3species. The decrease in the production of biomass at low N conditions was most drastic with Panicum crus-galli, the species with the lowest nitrogen content and thus assumed to be best adapted to nitrogen starvation conditions. In cultures growing at low nitrogen fertilization levels the shoot/root ratios of all species.shifted in favour of an increasing root proportion. The extent of this shift, however, differed from species to species.
authors.affiliation: Institut für Botanik und Mikrobiologie der Technischen Universität München, Arcisstr. 21, D-8000, München 2.
authors.forename: G
authors.initials: G
authors.lastname: Gebauer
authors.affiliation: Institut für Botanik und Mikrobiologie der Technischen Universität München, Arcisstr. 21, D-8000, München 2.
authors.forename: B
authors.initials: B
authors.lastname: Schubert
authors.affiliation: Centro de Ecologia, Universidad National de Cordoba, Argentina.
authors.forename: M I
authors.initials: MI
authors.lastname: Schuhmacher
authors.affiliation: Institut für Botanik und Mikrobiologie der Technischen Universität München, Arcisstr. 21, D-8000, München 2.
authors.forename: H
authors.initials: H
authors.lastname: Rehder
authors.affiliation: Institut für Botanik und Mikrobiologie der Technischen Universität München, Arcisstr. 21, D-8000, München 2.
authors.forename: H
authors.initials: H
authors.lastname: Ziegler
keywords: Biomass production; C3 grasses; C4 grasses; Competition; Nitrogen use efficiency