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Because of current environmental legislation in European grass-based farming, there is a need to develop tools that can link nitrogen (N) production with losses to the environment. A mass balance empirical model (NCYCLE) is proposed to fulfil this role. This study describes the principles and stages to develop a mass balance N cycle model for Irish grasslands using the basis of the existing NCYCLE model. The model was reconstructed and validated using empirical data from herbage cutting experiments in different Irish conditions and new functions were incorporated to improve the predictions. Irish data on agroclimatic regions and atmospheric deposition were used to provide site specific calculations. Outputs from the model are presented and appear to agree reasonably well with measured data from Ireland.

The Zumwalt Prairie in northeastern Oregon is the last large remnant of the Pacific Northwest Bunchgrass Prairie. Compared to other prairies in North America, relatively little is known about these arid temperate grasslands as the majority disappeared quickly after Euro-American settlement. In this paper we describe the landscape history of the Zumwalt Prairie through interpretation of historical aerial photos. Beginning with photos taken in 1938, we examined photos for area of cultivation and woody vegetation and number of buildings and stock ponds. Using data collected in 1976 and 2001, area of woody vegetation was further classified as aspen (Populus tremuloides, Michx.), conifers, and shrubs for analysis of trends. Area in cultivation and number of buildings decreased over the 67 years we examined. In contrast, the number of stock ponds increased. Overall, the area of woody species increased over the period of study; area of aspen declined while acreage of conifers and shrubs increased. The ...

We studied carbon balances and carbon stocks of mountain rangelands and meadows in a network of 8 eddy covariance sites and 14 sites with biomass data in Europe. Net ecosystem exchange of pastures and extensively managed semi-natural rangelands were usually close to zero, while meadows fixed carbon, with the exception of one meadow that was established on a drained peatland. When we accounted for off-site losses and inputs also the carbon budget of meadows approached zero. Soil carbon stocks in these ecosystems were high, comparable to those of forest ecosystems, while carbon stocks in plant biomass were smaller. Since soil carbon stocks of abandoned mountain grasslands are as high as in managed ecosystems, it is likely that the widespread abandonment of mountain rangelands used currently as pastures will not lead to an immediate carbon sink in those ecosystems.

Biomass of soil Acarina in arctic tundra near Barrow, Alaska was estimated from high gradient Tullgren extractions of core samples taken during the ice-free season of 1972. Adult and immature weights of abundant species are reported and regression equations are given for estimating weights from linear dimensions. A mean biomass of 99.9 mg m-2 (dry weight) was found, with a range of values between microhabitats of 15.4 and 182.6 mg m-2. Biomass characteristics in nine microhabitats are discussed and compared with acarine biomass of temperate grassland and forest.