Cattle trampling reduces the risk of nitrate leaching in organic dairy rotations

Organic dairy farming is characterized by grazing cows in contrast to Danish conventional farms where the majority of cows are kept indoors. Cattle trampling reduces the finer macroporosity in the top 5-10 cm of the soil. This causes a low infiltration capacity at the soil surface, giving a higher probability of macropore flow from the surface. Rapid water movement through macropores bypasses the soil matrix, reducing nitrate leaching. We investigated how three years of cattle trampling in organic grass-clover fields could influence the risk of nitrate leaching in the autumn. The experimental part of this study was situated in Denmark on a loamy sand within a long-term organic dairy crop rotation trial. Experimental plots were irrigated with a concentrated solution of potassium bromide (18.5 mm for an hour). The amount of bromide in the soil water was determined at five depths (0.1, 0.3, 0.4, 0.75 and 1.0 m) 24 h after irrigation. Macropores larger than 1 mm were recorded on horizontal surfaces (0.70 m2) at the same depths. Earthworm density and biomass were registered. Bromide concentration in soil was significantly larger with the grazing regime than with the cutting regime below 0.3 m depth to at least 1 m. We observed equivalent macropore densities between the two treatments, both at 0.1 and at 0.3 m depth. The dry bulk density measured at 10 cm depth was significantly larger in the plots with the grazing regime than with the cutting regime, indicating a reduction of the porosity at this depth for the plots subjected to cattle trampling. No epigeic species were present. Cattle trampling affected mainly endogeic earthworms. Deep-burrowing species (anecic) were the least sensitive to cattle trampling. The deeper infiltration of water in soil when subjected to cattle trampling indicated that preferential flow through large macropores occurred, and that rain water may bypass the soil matrix under similar or more extreme conditions than this experiment. We expect such hydraulic functioning to reduce the risk of leaching of soil water nitrate

Changes in environment cause dietary shifts in the Svalbard Arctic fox: A stable isotope study

In this thesis, shift in diet of Arctic foxes on Svalbard over a long time frame was analyzed. The Svalbard Arctic fox is a generalist who links the terrestrial and marine ecosystems. The objectives were 1) investigate whether there are spatial and temporal trends in Arctic fox diet on Svalbard, 2) determine how important the changes in the environmental variables are for dietary shifts of the Arctic fox in different seasons and 3) determine whether other parameters like the distance to the coast and age class have any impact on the diet as inferred from stable isotopes. Stable isotope values of carbon and nitrogen from Arctic fox muscle (representing winter diet) and fur (representing autumn diet) samples over the winter seasons 1997/1998 to 2019/2020 were used to assess dietary shifts. Arctic fox isotope values fitted mainly linearly between marine and resident terrestrial prey (reindeer and ptarmigan). Both negative temporal trends and differences between regions were found, signifying a shift towards more use of terrestrial resources in both winter and autumn. This was also found when analyzing environmental effects, where the number of geese and year to year fluctuations in reindeer carcass number were significant in shifting diet towards more use of terrestrial resources in winter. The distance to the coast also showed significant difference in the diet between coastal and inland Arctic foxes. The value of long time data series was shown in this thesis as these gave significant results, while short time data series usually did not. Continued monitoring and sampling, as well as including other parameters like seabird population estimates and the fox’s preference of marine invertebrates are of interest to improve models and give more accurate estimates

Content of fatty acids, vitamin E and carotenoids in milk and herbage as affected by sward composition and period of grazing

The quality of organic milk is affected by feed composition, and especially the high use of legumes has been identified as the reason for high levels of polyunsaturated fatty acids, carotenoids and tocopherols in organic milk. Four different pastures composed of mainly white clover (WCL), red clover (RCL), lucerne (LUC) or chicory (CIK), respectively, were established to investigate the influence of sward composition on the milk quality of grazing cows. On three occasions during the grazing period (May, June and August), groups of 12 Holstein cows were grazing the pastures for two weeks. About 70% of the daily dry matter intake was pasture, and the remaining dry matter intake was a mixture of oats, hay and minerals (82%, 16%, 2%, respectively). The swards were sampled, and their feed quality as well as their composition of carotenoids, tocopherols and fatty acids was analysed. On each occasion, milk was sampled after two weeks of grazing, and the content of tocopherols and carotenoids as well as the composition of fatty acids was analysed. The overall feed quality expressed as IVOMD (in vitro organic matter disappearance) and NDF (neutral detergent fibre) was affected by period and to a lesser extent by forage type. The content of carotenoids was higher in RCL compared to the other forages, while no effect of period was observed. Alpha-tocopherol was neither affected by period nor by forage type. Fatty acid content, in particular content of linolenic acid, decreased during the grazing period, and it was highest in RCL, intermediate in CIK and lowest in WCL and LUC. Milk yield was neither affected by period nor by forage type. Milk fatty acid composition and content of alpha-tocopherol and carotenoids showed minor differences between forage types and sampling occasions. However, multivariate analysis of these data showed grouping according to sampling occasion, but no clear grouping according to forage types. Despite the differences in composition of forage and in composition of milk, it was not possible to predict milk content of specific fatty acids, carotenoids or tocopherols from the feed content of these compounds. This was partly explained by differences in feed digestibility. Comparison of the milk with previous studies showed higher concentrations of beneficiary compounds such as linolenic acid (12 mg/g fatty acids), conjugated linoleic acid (13 mg/g fatty acids), carotenoids (6 µg/g milk fat) and alpha-tocopherol (21 µg/g milk fat), and it was concluded that all the forages tested could be used in production of a milk with such properties

Basic linear algebra subprograms for FORTRAN usage

A package of 38 low level subprograms for many of the basic operations of numerical linear algebra is presented. The package is intended to be used with FORTRAN. The operations in the package are dot products, elementary vector operations, Givens transformations, vector copy and swap, vector norms, vector scaling, and the indices of components of largest magnitude. The subprograms and a test driver are available in portable FORTRAN. Versions of the subprograms are also provided in assembly language for the IBM 360/67, the CDC 6600 and CDC 7600, and the Univac 1108

Analysis of the Copenhagen Accord pledges and its global climatic impacts‚ a snapshot of dissonant ambitions

This analysis of the Copenhagen Accord evaluates emission reduction pledges by individual countries against the Accord's climate-related objectives. Probabilistic estimates of the climatic consequences for a set of resulting multi-gas scenarios over the 21st century are calculated with a reduced complexity climate model, yielding global temperature increase and atmospheric CO2 and CO2-equivalent concentrations. Provisions for banked surplus emission allowances and credits from land use, land-use change and forestry are assessed and are shown to have the potential to lead to significant deterioration of the ambition levels implied by the pledges in 2020. This analysis demonstrates that the Copenhagen Accord and the pledges made under it represent a set of dissonant ambitions. The ambition level of the current pledges for 2020 and the lack of commonly agreed goals for 2050 place in peril the Accord's own ambition: to limit global warming to below 2 °C, and even more so for 1.5 °C, which is referenced in the Accord in association with potentially strengthening the long-term temperature goal in 2015. Due to the limited level of ambition by 2020, the ability to limit emissions afterwards to pathways consistent with either the 2 or 1.5 °C goal is likely to become less feasibl