Planteproduktion og fødevalg

Den overordnede baggrund for projektet var at få nogle kvantitative beskrivelser af, hvorledes man med forskellige former for ekstensiv græsmarksdrift kunne besvare eller øge artsdiversiteten på ferske enge. Samtidig ønskedes at kvantificere konsekvenserne for den landbrugsmæssige produktion på arealerne. Ferske enge varierer meget med hensyn til plantebestand, jordbundsforhold og fugtighed, og det er derfor væsentligt at kende disse faktorer, når man skal vurdere, hvilken produktion, der kan forventes på et givet engareal. Når stude og får afgræsser på halvkulturarealer er der et større udvalg af arter end der er på intensive græsmarker. Desuden er der som regel en lavere belægning, hvilket betyder at dyrene har gode muligheder for at selektere i det planteudbud, der er til rådighed. Målet med denne del af undersøgelsen var at få en beskrivelse af produktionens størrelse, foderkvalitet, artssammensætning, benyttelsens indvirkning på arterne, foderkvaliteten af enkeltarter og studenes fødevalg

Animal production from dairy breed steers at extensively managed grasslands in riverside areas

In Denmark, some of the grassland in marginal areas are abandoned for agricultural use - grassland that it is of interest to preserve because they have a high actural or potential natural quality when managed with extensive grazing or cuttting. A comparison was carried out for three years on sward productivity and weight gain of the steers at two grazing intensities on wet semi-natural grassland. The daily weight gain of steers was on average 667 g at low and 477 g at high grazing intensity. Sward grass yield as dry matter (DM) production was on average 4.1 Mg DM ha4, with no significant difference sound between the two gazing intensities. In vitroorganic matter digestibility (IVOMD) was rexpectigely 56.4 and 53.0 at high and low grazing intensity. It is concluded that the variatin in sward productivity and sward composition between years and grazing intensities was reflected in the production of the steers

Sward structure measurements to monitor the effect of grazing in nature management situations

In Denmark private farmers under contract with the society manage many nature conservation areas on low-lying organic soil. In the contract the grazing system is poorly difined in relation to the goals and there is a lack of monitoring intruments for practical use in natural areas. Thus there is a need to define grazing system indicators, which should make it possible toevaluate effect from grazing and provide a feed-back to the goals. To describe the effect of grazing on the vegetation structure, detailed measurements of sward heights, species composition, species phenology, distance to flowering speecimens of Juncus effeusus I. or J. conglomeratus I. were carried out in paddocks grazed by 1st year steers at two different levels of plant species diversity and at two levels of grazing intensity. The aim was to identify variables able to ecpose the effect of the different treatments