Search

The widespread use of warm-season turfgrasses in transition zones of Europe, such as northern Italy, has been hampered by the long dormancy periods. To encourage the conversion from cool- to warm-season grasses, research is needed to identify cultivars that exhibit early spring green-up. A 2-year study was conducted at the agricultural experimental farm of Padova University from November 2006 to October 2008 to compare water-soluble carbohydrate and protein content in stolons of four bermudagrass [ Cynodon dactylon (L.) Pers.] cultivars and determine their effect on spring green-up. Samples of 'La Paloma', 'NuMex Sahara', 'Princess 77' and 'Yukon' were collected monthly, and water-soluble carbohydrates ( WSC) and crude protein ( CP) content of stolons were measured. Dry weight values of WSC and CP for each cultivar were regressed against days needed to reach 80 % green cover in spring (D80). 'Yukon' exhibited the highest rhizome dry weight and WSC content during the winter months and was the fastest to reach 80 % green cover. Conversely, 'Princess 77' was the slowest cultivar to green-up in both years. Regression analysis revealed a stronger relationship between D80 and WSC than between CP content and D80. [ABSTRACT FROM AUTHOR]

Many mountain pastures consist of a mosaic of grassland and shrub communities. Ongoing changes in mountain agriculture have affected the balance between the two elements of the mosaic. In order to understand the consequences of these changes for ecosystem functioning, we studied patterns in vegetation, root structure and soil properties along transects of varying grassland-to-shrub proportions. Our hypothesis was that differences in the vegetation aboveground are accompanied by differences belowground, related to soil properties and depth. The research was conducted at a subalpine site in the Trentino region (South-eastern Alps), consisting ofNardus strictagrasslands alternating with shrub patches ofRhododendron ferrugineum. Our investigation showed that the composition of vegetation was mainly governed byR. ferrugineumcover and less by soil properties. Plant species richness peaked at low to intermediate degrees of shrub cover and composition between transects became more similar with increasing shrub cover. WhereR. ferrugineumcover was higher, Hemicryptophytes caespitosae were replaced by Nano-phanerophytes with consequences for belowground structures. At increasing shrub cover, root length density decreased, especially in the top soil, while root weight density remained stable and C content increased insignificantly. We discuss that theses structural changes along the gradient ofR. ferrugineumcover affect a number of ecosystem services. The presented evidence suggests that maintaining grasslands with a low cover ofR. ferrugineumbalances a number of services, namely plant species diversity, carbon stabilization in soil and the prevention of soil erosion. [ABSTRACT FROM AUTHOR]

Kentucky bluegrass (Poa pratensis L.) is a perennial cool-season grass commonly used for sport and ornamental turfgrasses in transition zones. It is a rather difficult species to establish due to slow germination and the relatively moderate growth rate of seedlings. Early autumn is considered the best time for sowing Kentucky bluegrass in temperate regions. Spring sowing is not recommended as low soil moisture and high temperatures can have a negative impact on germination. However, unavoidable circumstances often force turfgrasses to be sown in spring with high probability of failure. The risk of failure may increase in the near future as a consequence of climate change, so more knowledge is required on the ability of Kentucky bluegrass cultivars to germinate at high temperatures. A laboratory study evaluated the germination response of fourteen cultivars selected among those most used in northern Italy. They were compared in a conditioning chamber under five regimes of alternating temperatures (20/30 °C, 23/33 °C, 26/36 °C, 29/39 °C, 32/42 °C). Germination was recorded weekly starting from sowing. The germination patterns were similar up to 26/36 °C. At 29/39 °C only five cultivars had a germination of over 50%. At the highest temperature regime none of the cultivars had more than 3% germination. It is concluded that only when very extreme high temperatures occur, growers need to pay attention to the choice of cultivars to avoid problems during the germination-emergence phase, but based on the climate change scenario this is likely to happen with greater frequency in the future. [ABSTRACT FROM AUTHOR]