Soil conservation policy in the United States

Soil conservation has been a matter of federal natural resource policy for over a half century in the United States. A variety of federal programs have been undertaken to encourage soil conservation. There are goals which are essential to these programs, and there are related ancillary programs with different goals which often have had an impact on the extent to which the central soil conservation objectives have been effectively implemented. This article analyzes four aspects of federal soil conservation goals and programs: the evolution of the constellation of soil conservation goals, the problems with goal implementation, implementation effectiveness, and the appropriateness of the implementation and administration of federal goals.     

Societal risk assessment of major hazard installations using QuickRisk

QuickRisk is a quantitative risk assessment tool developed at the Health and Safety Laboratory for use in assessing societal risk around onshore major hazard installations to inform land-use planning decisions. It uses release scenario information, parameterised consequence models, weather data, and population data from the National Population Database (NPD).This paper describes enhancements to the NPD methodology to include workplace populations. It describes the novel numerical, graphical and geographical representations of societal risk produced by QuickRisk. F–N data are analysed in terms of scenario FN curves and Delta PLL vs. N curves, where PLL is potential loss of life. The Delta PLL curves could be useful for comparison of FN curves against FN criterion lines or other FN data on a PLL basis. Geographical representations generated from PLL density maps show: the distribution of PLL dominating release scenarios or the percentage of risk contributed by the PLL-dominant release scenario, the maximum number of fatalities associated with the worst-case event, and the associated release scenario. Geographical representations are also generated of the maximum population that would meet a PLL density criterion, and the relative population change that would match a given PLL density criterion.These novel representations of societal risk could be useful for more effective communication between stakeholders on the risk levels in the vicinity of major hazard installations.     

Rangeland dynamics in southern Ethiopia: (1) botanical composition of grasses and soil characteristics in relation to land-use and distance from water in semi-arid Borana rangelands

The distribution and compositional pattern of the grass layer, as well as soil quality of southern Ethiopian semi-arid rangelands were examined under three land-use systems (communal land, government ranch and a traditional grazing reserve enclosure) and along a distance gradient (near, middle and far) from water sources. In total, 49 grass species were identified, 65% of which were perennials. Of the most commonly distributed highly desirable species, Chrysopogon aucheri showed the greatest frequency under the traditional grazing reserve (27.6%), and the lowest in the communal land (14.0%). The frequency of Cenchrus ciliaris was similar in all the study sites. The proportion of Lepthotrium senegalensis was low under the land-use systems (3.9%) and increased away from water sources (2.3%). Of the less desirable species, Sporobulus nervosus was extremely more abundant (<0.05) in the communal land (13.3%) than the traditional grazing reserve (3.3%) and the government ranch (1.9%). Sporobolus pyramidalis was dominant in the study sites, with similar (P>0.05) frequency percentages under the land-use systems and along the distance gradients from water. Basal cover was low and similar on all the study sites (3.3%). Concerning the soil texture, sand (71.1%) constituted the largest proportion, followed by silt (21.3%) and lastly, clay (7.7%). With regard to soil exchangeable cations, organic C and total nitrogen were generally low and did not show marked variation in all the study sites. The study showed significant differences for most of the vegetation variables between the communal land and the other land-uses. This suggested that grazing intensity was higher in the communal land and moderate in the government ranch and in the traditional grazing reserves (kallos). The lack of significant differences in most of the studied (vegetation) variables along the distance gradient from water could be ascribed to the fact that grazing disturbance has already exceeded a certain threshold of degradation. Under the present low states of soil nutrients and rainfall, cultivation is neither sustainable nor environmentally friendly and this will lead to further degradation of the soil in these marginal lands.     

Socio-economic driving forces of land-use change in Kunshan, the Yangtze River Delta economic area of China

This paper analyzes characteristics, major driving forces and alternative management measures of land-use change in Kunshan, Jiangsu province, China. The study used remote sensing (RS) maps and socio-economic data. Based on RS-derived maps, two change matrices were constructed for detecting land-use change between 1987 and 1994, and between 1994 and 2000 through pixel-to-pixel comparisons. The outcomes indicated that paddy fields, dryland, and forested land moderately decreased by 8.2%, 29% and 2.6% from 1987 to 1994, and by 4.1%, 7.6% and 8% from 1994 to 2000, respectively. In contrast, the following increased greatly from 1987 to 1994: artificial ponds by 48%, urban settlements by 87.6%, rural settlements by 41.1%, and construction land by 511.8%. From 1994 to 2000, these land covers increased by 3.6%, 28.1%, 23.4% and 47.1%, respectively. For the whole area, fragmentation of land cover was very significant. In addition, socio-economic data were used to analyze major driving forces triggering land-use change through bivariate analysis. The results indicated that industrialization, urbanization, population growth, and China's economic reform measures are four major driving forces contributing to land-use change in Kunshan. Finally, we introduced some possible management measures such as urban growth boundary (UGB) and incentive-based policies. We pointed out that, given the rapidity of the observed changes, it is critical that additional studies be undertaken to evaluate these suggested policies, focusing on what their effects might be in this region, and how these might be implemented.