Eco-Efficiency of Forage Production in Northern Germany

A 2-year field experiment was conducted at two sites in Schleswig-Holstein, northern Germany, to quantify and evaluate the carbon footprint of arable forage cropping systems (continuous silage maize, maize-wheat-grass rotation, perennial ryegrass ley) as affected by N fertilizer type and N amount. Total greenhouse gas emission showed a linear increase with N application, with mineral N supply resulting in a higher slope. Product carbon footprint ranged between -66 and 119 kg CO2eq/(GJ NEL) and revealed a quadratic or linear response to fertilizer N input, depending on the cropping system. At N input required for achieving maximum energy yield, perennial ryegrass caused lower emission per product unit than continuous maize or the maize-wheat-grass rotation. The data indicate potential for sustainable intensification when crop management options are adopted to increase resource use efficiency

Differential effects of habitat isolation and landscape composition on wasps, bees, and their enemies

Habitat loss and fragmentation are major threats to biodiversity and ecosystem functioning. Effects of these usually intercorrelated processes on biodiversity have rarely been separated at a landscape scale. We studied the independent effects of amount of woody habitat in the landscape and three levels of isolation from the next woody habitat (patch isolation) on trap nesting bees, wasps, and their enemies at 30 farmland sites in the Swiss plateau. Species richness of wasps was negatively affected by patch isolation and positively affected by the amount of woody habitat in the landscape. In contrast, species richness of bees was neither influenced by patch isolation nor by landscape composition. Isolation from woody habitats reduced species richness and abundance of natural enemies more strongly than of their hosts, so that parasitism rate was lowered by half in isolated sites compared to forest edges. Thus, population regulation of the hosts may be weakened by habitat fragmentation. We conclude that habitat amount at the landscape scale and local patch connectivity are simultaneously important for biodiversity conservatio

Lachgasemission und Nitratauswaschung verschiedener Futterproduktionssysteme in Abhängigkeit von der Vornutzung

Intensified agriculture is often associated with nitrous oxide (N2O) emissions and nitrate (NO3) leaching losses into groundwater due to high application rates of N-fertilizer, increasing maize cultivation and ploughing up permanent grassland. N2O is an important anthropogenic greenhouse gas and agriculture is one of the main polluters. NO3 leaching endangers groundwater quality. In a field experiment on the organically managed farm “Lindhof” in Northern Germany three different forage production systems (1. crop rotation, 2. continuous silage maize 3. permanent grassland) were established parallelly after a) ploughing up permanent grassland and b) longtime arable use. N2O emissions were measured weekly over the two-year experimental period. Soil water samples were taken over the leaching season (Oct-Mar) once a week and analysed for N-content. The production systems “crop rotation” and “continuous maize” showed significant higher amounts of N2O emissions and NO3 leaching than the newly established or resown grassland. In the system “crop rotation”, maize after grass-clover had the highest emissions, because of high N-mineralization of clover residues, both during and after growing season. Long-term cropping history and manure application had no significant effects, but on plots established on former grassland, emissions and leaching tended to be higher

Sprachlernberatung im schulischen Kontext. Förderung der Kompetenzen im Lehramt

Im Rahmen eines Stichwortbeitrags präsentieren die AutorInnen schließlich den Begriff und das Konzept der Sprachlernberatung und analysieren, wie diese spezifische Form der Beratung im schulischen Kontext effektiv stattfinden kann, welche Kompetenzen Lehrkräfte dafür benötigen und wie diese gefördert werden könnten. (DIPF/Orig.

Isolation from forest reduces pollination, seed predation and insect scavenging in Swiss farmland

Habitat loss and fragmentation lead to changes in species richness and composition which may affect ecosystem services. Yet, few studies distinguish between the effects of habitat loss and isolation, or how multiple ecosystem services may be affected simultaneously. We investigated the effects of variation in cover of woody and open semi-natural habitats and isolation from forest on the relative functioning of pollination, seed predation and insect scavenging in agricultural landscapes. We established 30 sites in grassland locations in the Swiss plateau around Berne. The sites varied independently in their isolation from forest edges, in the percentage of woody habitats and in the percentage of open semi-natural habitats in the surrounding landscape (500m radius). We experimentally exposed primroses, sunflower seeds and cricket corpses during spring 2008. None of the three studied services was affected by variation in woody or open semi-natural habitat cover. However, the proportion of flowers setting seed was significantly reduced by isolation from forest. Further, seed predation and insect scavenging were significantly lower at isolated sites than at sites connected to woody habitat. This pattern was particularly pronounced for seeds and insect corpses that were enclosed by wire netting and thus inaccessible to vertebrates. Thus, all three studied services responded quite similarly to the landscape context. The observed small-scale determination of seed set, seed predation and insect scavenging contrasts with larger-scale determination of pollination and insect pest control found in other studie

Yield Progress in Forage Maize in NW Europe—Breeding Progress or Climate Change Effects?

Yield increases in forage maize (Zea mays L.) in NW Europe over time are well documented. The driving causes for these, however, remain unclear as there is little information available regarding the role of plant traits triggering this yield progress. Ten different hybrids from the same maturity group, which have typically been cultivated in Northwest Germany from 1970 to recent and are thus representing breeding progress over four decades, were selected for a 2-year field study in northern Germany. Traits that were investigated included leaf area index, leaf architecture, photosynthesis, radiation use efficiency, root mass, root length density, and turnover. Based on a mixed model analysis with these traits as co-variates, parameters related to leaf characteristics, in particular the number and length of leaves, the radiation use efficiency, and the leaf orientation, were identified as most influential on the yield progress (0.13 tons ha-1 year-1). In contrast to our hypothesis, root biomass only increased negligibly in newer hybrids compared to older ones, confirming the ‘functional equilibrium’ theory for high input production systems. Due to an abundance of nutrients and water in such high input systems, there is no incentive for breeders to select for carbon partitioning toward the rooting system. Breeding evidence to increase forage quality were also negligible, with no change in cob starch concentration, forage digestibility, nor NDF content and NDF digestibility. The observed increase in yield over the last four decades is due to a combination of increased temperature sums (~240 GDD within 40 years), and a higher radiation interception and radiation use efficiency. This higher radiation interception was driven by an increased leaf area index, with a higher number of leaves (16 instead of 14 leaves within 40 years) and longer leaves of newer compared to older hybrids. Future selection and adaptation of maize hybrids to changing environmental conditions are likely to be the key for high productivity and quality and for the economic viability of maize growing and expansion in Northern Europe