Root biomass and carbon storage in differently managed multispecies temporary grasslands

Species-rich grasslands may potentially increase carbon (C) storage in soil and an experiment was established to investigate C storage in highly productive temporary multi-species grasslands. Plots were established with three mixtures: 1) a herb mixture containing salad burnet (Sanguisorba minor L.), fenugreek (Trogonella foenum-gruecum), chicory (Chicorium intybus L.), caraway (Carum carvi L.), birdsfoot trefoil (Lotus corniculatus L.), chervil (Anthriscus cerefolium L.), plantain (Plantago lanceolata L.), lucerne (Medicago sativa L.) and melilot (Melilotus officinalis), 2) 50% of the herb mixture and 50% of a white clover (Trifolium repens L.)/perennial ryegrass (Lolium perenne L.) mixture, and 3) 5% of the herb mixture and 95% of the white clover/ryegrass mixture. Management factors were number of cuts per year and fertilizer application. Aboveground biomass increased considerably with increasing content of herbs and with fertilizer application in plots with a 4-cut strategy. With a 6-cut strategy without fertilizer herbs had no effect on the aboveground biomass. In the herb mixture biomass of small roots was lower than in mixtures with white clover and ryegrass. There was a tendency towards increased biomass in the large root fraction with increasing herb content. The experiment indicated increased CO2 evolution following cultivation of multispecies grasslands

Management of forb species mixtures for high biomass production

Including forb species in grassland mixtures may secure a more biodiversity-friendly production of biomass. This experiment showed interesting future perspectives in terms of production of low-cost biomass for e.g. biogas production, which can be obtained by reducing the number of cuttings without compromising yield levels. No significant differences in dry matter (DM) yields of chicory, birdsfoot trefoil, yarrow and a 13 species mixture were observed between the situations with four compared to one autumn cut per year. Especially the 13 species mixture showed great potential in terms of yield and suppression of unsown species, for which reasons it should be developed further through knowledge on the species in pure stands

Effect of seed mixture composition and management on competitiveness of herbs in temporary grasslands

In multispecies grasslands the proportion of different herb species may vary considerably due to low competitiveness of some herbs. To examine the possibility for increasing the competitiveness an experiment with three factors were set up: 1) amount of herb seed in a perennial ryegrass (Lolium perenne), white clover (Trifolium repens) mixture, 2) slurry application and 3) cutting frequency. The experiment was carried out over two years. The herbs mix contained salad burnet (Sanguisorba minor), fenugreek (Trogonella foenum-gruecum), chicory (Chicorium intybus), caraway (Carum carvi), birdsfoot trefoil (Lotus corniculatus), chervil (Anthriscus cerefolium), plantain (Plantago lanceolata), Lucerne (Medicago sativa) and melilot (Melilotus officinalis). The proportion of herb seeds was 5, 25, 50 or 100 %. The herb species were most competitive in the first harvest year. In the second year the proportion of all herb species were very low in the mixtures, where white clover and perennial ryegrass were represented. The proportion of many herbs were higher at a 7-cut than at a 4-cut management, and application of cattle slurry also affected the competitiveness. In general chicory, caraway and plantain were the strongest competitors, salad burnet and birdsfoot trefoil were intermediate, and melilot, fenugreek and chervil were very weak competitors

Maps of random walks on complex networks reveal community structure

To comprehend the multipartite organization of large-scale biological and social systems, we introduce a new information theoretic approach that reveals community structure in weighted and directed networks. The method decomposes a network into modules by optimally compressing a description of information flows on the network. The result is a map that both simplifies and highlights the regularities in the structure and their relationships. We illustrate the method by making a map of scientific communication as captured in the citation patterns of more than 6000 journals. We discover a multicentric organization with fields that vary dramatically in size and degree of integration into the network of science. Along the backbone of the network -- including physics, chemistry, molecular biology, and medicine -- information flows bidirectionally, but the map reveals a directional pattern of citation from the applied fields to the basic sciences.Comment: 7 pages and 4 figures plus supporting material. For associated source code, see http://www.tp.umu.se/~rosvall

Sensory quality of organic milk based on grazing and high ratio of legumes in the feeding ration

Organic milk forms an important segment of the fresh milk production in Denmark. However, studies are needed to substantiate the high quality and future development of new variations of organic milk for different consumers. Differences in the composition of organically and conventionally produced milk (free fatty acids and a higher content of antioxidants in organic milk) are suggested to be a result of differences in feeding regimes (maize components in conventional production vs. grass and legumes in organic production). Also, milk from dairy cows fed grass silage has a different flavour compared to milk from dairy cows fed maize silage. This study evaluated the sensory properties of organic milk from dairy cows from different feeding trials. The effect of four different legumes and herbs, lucerne (Medicargo sativa), red clover (Trifolium pratense), white clover (Trifolium repens) and chicory (Cichorium intybus), was studied following a schedule including 4*12 Holstein Frisian cows. Descriptive sensory analysis was performed on the fresh pasteurized unhomogenized full-fat milk (6 replicates in 2 sessions) with a trained panel of 10 assessors. The preliminary results from the descriptive analysis of summer feeding (grazing) and winter feeding (silage) show that feeding with legumes and grass affects the sensory quality of full-fat unhomogenized organic milk. The most distinct milk was obtained from feeding ration high in chicory. This milk was characterized by a bitter and metallic taste and an astringent aftertaste both from the summer grazing and winter silage feeding trials. Red clover was characterized by a boiled milk flavour (summer), lucerne by a fatty aftertaste (winter) and white clover by a sweet and creamy flavour (winter). The results of the first season, which will also include relations between the sensory quality and the milk composition, serve as important inputs for the extensive studies to be conducted during the next three seasons. These studies include farm studies and consumer studies (product information, preference and purchase motives)