Salt-induced land and water degradation in the Aral Sea basin: A challenge to sustainable agriculture in Central Asia

Expansion of irrigated agriculture in the Aral Sea Basin in the second half of the twentieth century led to the conversion of vast tracks of virgin land into productive agricultural systems resulting in significant increases in employment opportunities and income generation. The positive effects of the development of irrigated agriculture were replete with serious environmental implications. Excessive use of irrigation water coupled with inadequate drainage systems has caused large‐scale land degradation and water quality deterioration in downstream parts of the basin, which is fed by two main rivers, the Amu‐Darya and Syr‐Darya. Recent estimates suggest that more than 50% of irrigated soils are salt‐affected and/or waterlogged in Central Asia. Considering the availability of natural and human resources in the Aral Sea Basin as well as the recent research addressing soil and water management, there is cause for cautious optimism. Research‐based interventions that have shown significant promise in addressing this impasse include: (1) rehabilitation of abandoned salt‐affected lands through halophytic plant species; (2) introduction of 35‐day‐old early maturing rice varieties to withstand ambient soil and irrigation water salinity; (3) productivity enhancement of high‐magnesium soils and water resources through calcium‐based soil amendments; (4) use of certain tree species as biological pumps to lower elevated groundwater levels in waterlogged areas; (5) optimal use of fertilizers, particularly those supplying nitrogen, to mitigate the adverse effects of soil and irrigation water salinity; (6) mulching of furrows under saline conditions to reduce evaporation and salinity buildup in the root zone; and (7) establishment of multipurpose tree and shrub species for biomass and renewable energy production. Because of water withdrawals for agriculture from two main transboundary rivers in the Aral Sea Basin, there would be a need for policy level interventions conducive for enhancing interstate cooperation to transform salt‐affected soil and saline water resources from an environmental and productivity constraint into an economic asset.     

The multiple pathways of high performing groups: the interaction of social networks and group processes

This study examines how both strong and weak relationship groups (groups with numerous, intense internal friendship ties and few, less intense internal friendship ties respectively) achieve high performance when utilizing strategies that capitalize on the strengths and minimizing the weaknesses associated with their internal social structure. We examine the interactions of groups' internal friendship networks with their external network structures (external ties) and internal intragroup conflict (constructive controversy). The results of a study using survey, archival and interview data on 35 groups of MBA students indicated that internal friendship networks interacted with constructive controversy and external networks to determine when groups would achieve superior performance. High performing strong relationship groups engaged in greater constructive controversy than low performing strong relationship groups, while constructive controversy appeared to have minimal effect on the performance of weak relationship groups. High performing weak relationship groups had fewer external bridging ties to other groups when compared to low performing weak relationship groups, while external bridging ties appeared to have minimal effect on the performance of strong relationship groups. Copyright © 2006 John Wiley & Sons, Ltd.     

A study on traffic noise of two campuses of University, Balasore, India

Noise pollution is a significant environmental problem in many rapidly urbanizing areas of Orissa, India. Transportation sector is one of the major contributors to noise in these areas. The present study is an attempt to estimate traffic noise pollution at five places on the way from Vyasa Vihar Campus to Gyan Vigyan Vihar Campus of Fakir Mohan University, Balasore, Orissa. The sources of noise at the studied sites are predominantly attributable to motor vehicular traffic. The noise levels of all the five locations were found to be beyond permissible limit during the day time. The contributions of different types of vehicles to environmental noise were found to ranging from 70.4-94.2, 79.0-96.1, 77.8-110.2, 70.8-90.3, 71.0-87.5, 71.1-84.4, 72.5-86.9 and 74.0-85.4 dB (A) by cargo carrying Trucks, Tractors, Dumpers, Town Buses, Motor cycles, Bolero/Trucker, Pick up and Tempo respectively. The contributions of individual vehicles towards noise pollution were found to be more than the road traffic noise-limit i.e., 70 dB (A). On certain local inhabitants interviewed, the impact of noise was observed in the forms of alterations in their physical, psychological and personal aspects. This study warrants attention from all sections of people to deal with the problem of noise pollution.     

Ecosystem carbon budgeting and soil carbon sequestration in reclaimed mine soil

Global warming risks from emissions of green house gases (GHGs) by anthropogenic activities, and possible mitigation strategies of terrestrial carbon (C) sequestration have increased the need for the identification of ecosystems with high C sink capacity. Depleted soil organic C (SOC) pools of reclaimed mine soil (RMS) ecosystems can be restored through conversion to an appropriate land use and adoption of recommended management practices (RMPs). The objectives of this paper are to (1) synthesize available information on carbon dioxide (CO2) emissions from coal mining and combustion activities, (2) understand mechanisms of SOC sequestration and its protection, (3) identify factors affecting C sequestration potential in RMSs, (4) review available methods for the estimation of ecosystem C budget (ECB), and (5) identify knowledge gaps to enhance C sink capacity of RMS ecosystems and prioritize research issues. The drastic perturbations of soil by mining activities can accentuate CO2 emission through mineralization, erosion, leaching, changes in soil moisture and temperature regimes, and reduction in biomass returned to the soil. The reclamation of drastically disturbed soils leads to improvement in soil quality and development of soil pedogenic processes accruing the benefit of SOC sequestration and additional income from trading SOC credits. The SOC sequestration potential in RMS depends on amount of biomass production and return to soil, and mechanisms of C protection. The rate of SOC sequestration ranges from 0.1 to 3.1 Mg ha(-1) yr(-1) and 0.7 to 4 Mg ha(-1) yr(-1) in grass and forest RMS ecosystem, respectively. Proper land restoration alone could off-set 16 Tg CO2 in the U.S. annually. However, the factors affecting C sequestration and protection in RMS leading to increase in microbial activity, nutrient availability, soil aggregation, C build up, and soil profile development must be better understood in order to formulate guidelines for development of an holistic approach to sustainable management of these ecosystems. The ECBs of RMS ecosystems are not well understood. An ecosystem method of evaluating ECB of RMS ecosystems is proposed.     

Exchange of polycyclic aromatic hydrocarbons across the air-water interface at the creek adjoining Mumbai harbour, India

Concentration levels of polycyclic aromatic hydrocarbons (PAHs) have been determined in air and water in order to estimate the magnitude and direction of gas flux across the air-water interface at the creek adjoining the Mumbai harbour, India. The range of total PAHs was found to be 4.1-30.4 ng/m3 in air and 84.3-377.5 ng/l in seawater, respectively. The lower molecular weight PAHs revealed positive values of the fluxes indicating the tendency for transfer of these contaminants from water to air. In contrast, fluxes of less volatile compounds like benzo(k)fluoranthene and benzo(a)pyrene were always from the atmosphere into the surface water of the creek at all locations and sampling periods. While the fugacity ratio ranged from 0.12 to 6.97, it was found greater than 1 for the lower molecular weight PAHs and less than 1 for higher molecular weight PAHs. The present study suggests the active transfer of lower molecular weight dissolved PAHs into the atmosphere due to volatilization and deposition of higher molecular weight gas-phase PAHs into the surface water.     

Sustainable development and automation: are they compatible?

Summary The ecological crisis is a result of modern industrial development and its negative impacts which are not conducive to the co-existence of essential diversities in the ecosystem. One of the major trends in present day industry is to move towards computer-based automation. This article discusses the compatibility of this trend towards automation with sustainable development which is regarded as the only viable choice to overcome the ecological crisis. After discussing the present day concepts of sustainable development, automation and the economic impact of automation on society, this paper argues that computer-based automation in industry is not conducive to sustainable development. It is also argued that the spread of automation will decrease the capability of mankind as a whole to implement environmentally sustainable programmes. Finally, the man-nature relationship which is the philosophical basis of the industrial paradigm is discussed. As pointed out by some comparative philosophers, the basic concept of human superiority and separation from nature has to change in order to have a harmonious integrity of life forms as complementary realities in this phenomenal existence.Satyabrata Pradhan is a Post Doctoral Research Fellow of the Department of Mechanical Engineering at the University of British     

Effect of sewage water on the growth and yield parameters of wheat and blackgram with different fertilizer levels

Impact of biologically treated domestic sewage water was studied on the growth and yield attributing characters of wheat and blackgram under different fertilizer levels in the field condition. There was no significant difference on the yield and yield attributing characters of wheat. However, yield attributing characters like number of tillers/plant, panicle length (cm), number of grains/panicle and 1,000 grain weight showed increasing trend to the tune of 13.29, 1.59. 5.49 and 3.79 per cent respectively over the tubewell irrigated crop. Yield was also increased to the tune of 3.63 per cent when the crop was irrigated with sewage water. Interactions between irrigation and fertilizer levels were also insignificant. However, sewage water with N60P45K45 responded better on tillering, panicle length, number of grains/panicle and yield of wheat. In case of blackgram, treated sewage water had no significant effect on the grwoth and yield attributing characters, rather sewage water had some negative effect on these parameters. Interactions between irrigation and fertilizer levels were insignificant. But tubewell irrigation with N10P10K10 was more responsive on growth parameters. When the crop was grown with tubewell irrigation and without fertilizer, yield attributing characters were more positively responded.     

Tree species diversity and composition in logged and unlogged rainforest of Kudremukh National Park, South India

Species composition and diversity in logged and unlogged forests were assesed to understand the regeneration of the residual stand twenty years after logging in Kudremukh National Park, South India. Relative density, frequency and basal area were measured by Point Centered Quarter method to calculate the diversity and stand quality. The logged forest harbored lower stem density of mature trees (508 ha(-1)) than unlogged ones (630 ha(-1)). Indeed, logging operations increased the species diversity in the regenerative phase (seedling phase) due to the creation of larger canopy gaps. The extra radiation reaching the ground, facilitated the colonization of early and late secondary species. Ramakrishanan Index of Stand Quality (RISQ) values in logged forest was higher in comparison with unlogged forest, indicating the dominance of early and late secondary species, especially at sapling phase. The light demanding secondary forest species contribute higher percentage to the overall tree population in logged forest. It is observed from the study that a sufficient period of felling cycle should be practiced to reinstate the same set of species prevailed before logging.