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[en] During the last 50 years nitrate concentrations in Buttermere and Wastwater (Cumbria, UK) have risen significantly, by 70 and 100%, respectively. By estimating contemporary nitrate fluxes in the lakes' catchments and in sub-catchments and comparing them with the fractional areas of different soil types, it is deduced that the surface water nitrate is derived almost entirely from organic-rich ranker soils that have a limited ability to retain atmospherically-deposited nitrogen. Little or no nitrate leaches from the other major soil type, a brown podzol, despite it having a lower C:N ratio (12.0 g g-1) than the ranker (17.0 g g-1), nor is there much contribution from the small areas of improved (chemically fertilised) grassland within the catchments. Although some nitrate leaching is occurring, total N losses are appreciably smaller than atmospheric inputs, so the catchment soils are currently accumulating between 3 and 4 g N m-2 a-1. - Increases in lakewater nitrate concentrations over 50 years are due to the limited ability of ranker soils to retain atmospherically-deposited nitrogen
[en] Highlights: • Grass yields from marginal land were comparable with those from good agricultural land. • Perennial rhizomatous grasses such as festulolium outyielded perennial ryegrass when grown on marginal land. • Grass from marginal land in Ireland could provide enough energy to power both the private car and the heavy goods vehicle fleets. - Abstract: The production of biomass feedstock from marginal land has attracted much attention as a means of avoiding conflict between the production of food and fuel. Yield potentials from marginal lands have generally not been quantified although it is generally assumed that lower biomass yields can be expected from marginal lands. A three year study was conducted in Ireland in order to determine if grass yields of perennial rhizomatous grasses (cocksfoot, tall fescue, reed canary grass, festulolium) for anaerobic digestion from three marginal land sites (very wet site, very dry site, site prone to flooding) could match yields from better soils. Randomised complete block designs were established on each site in 2012 with two varieties of each grass species as treatments. Three grass harvests were taken from each site in 2013 and in 2014. There was no significant difference between yields from the control site and those from the very dry site and the site prone to flooding. Biomass yields from the very wet site were 85% of those from the control site. Highest yields were obtained from festulolium which were significantly higher than yields from perennial ryegrass. An energy analysis showed that maximising the production of grass from low lying mineral marginal grassland in Ireland could provide enough energy to meet the energy requirements of both the private car fleet and the heavy goods vehicle fleet while avoiding conflict with food production which could be concentrated on conventional land.
[en] Landscape surface features related to erosion and hydrology were measured using an airborne laser profiler. The airborne laser profiler made 4,000 measurements per second with a recording accuracy of 5 cm (1.9 inches) on a single measurement. Digital data from the laser are recorded and analyzed with a personal computer. These airborne laser profiles provide information on surface landscape features. Topography and canopy heights, cover, and distribution of natural vegetation were determined in studies in South Texas. Laser measurements of shrub cover along flightlines were highly correlated (R2 = 0.98) with ground measurements made with line-intercept methods. Stream channel cross sections on Goodwin Creek in Mississippi were measured quickly and accurately with airborne laser data. Airborne laser profile data were used to measure small gullies in a level fallow field and in field with mature soybeans. While conventional ground-based techniques can be used to make these measurements, airborne laser profiler techniques allow data to be collected quickly, at a high density, and in areas that are essentially inaccessible for ground surveys. Airborne laser profiler data can quantify landscape features related to erosion and runoff, and the laser proler has the potential to be a useful tool for providing other data for studying and managing natural resources
[en] Grazing behaviours of Teddy goats and Thalli sheep were studied on rangelands of ThaI. Bite count method was used to determine the dietary composition of both animal species. The overall preference of Teddy goats was higher for Khabble grass (Cynodon dactylon), which was 40.57% of the total number of bite made on different plant species during the study period (March-July). Teddy goats utilized a wide range of browsing plant species like Wan (Salvadora oleoides), Phog (Calligonum polygonoides), Babil (Acacia jacquemontii), Jandi (Prosopis spicigera) etc. Browsing species were major component (>50%) of goat diets dur- ing March through June. Whereas Thalli sheep had been consistent in their heavy use of Khabble grass (overall 89.27%). Browsing plant species were not an important component of their diets. Teddy goats and Thalli sheep were competitive for Khabble grass particularly at its vegetative growth stage. (author)
[en] The effects of elevated atmospheric CO2 on root dynamics were studied in a semi-natural grassland in central Sweden during five consecutive summer seasons. Open-top chambers were used for ambient and elevated (+350 μmol/mol) concentrations of CO2, and chamberless rings were used for control. Root dynamics were observed in situ with minirhizotrons during the five summers and root biomass production was measured with root in growth cores during the last two years, from which total root biomass was estimated for each of the five years. The elevated CO2 treatment showed both a greater increase in root numbers during the early summer and a greater decline in root numbers during autumn and winter than the ambient CO2 treatment. Mean root production under elevated CO2 was 50% greater than ambient CO2 during the five years, and the difference increased from +25% in the first year to +80% in the last two years. Conversely, during the same period, the elevated to ambient CO2 difference in shoot biomass decreased from +50% to +5%. This resulted in a dramatic change in root to shoot ratios in elevated CO2 compared with the ambient treatment, which increased from -15% in 1996 to +70% in 2000. Similar differences were seen between elevated CO2 and the chamberless grown control plants, where root to shoot ratios increased steadily from -47% in 1996 to +27% in 2000. Less dynamically, the root to shoot ratios of ambient CO2 grown plants compared with the chamberless control plants were consistently -29% ±6% during the experimental period. In conclusion, during the 5 years this grassland was studied, there was a clear shift in plant biomass partitioning from above to below ground for plants exposed to elevated CO2