Soil respiration,labile carbon pools,and enzyme activities as affected by tillage practices in a tropical rice–maize–cowpea cropping system

In order to identify the viable option of tillage practices in rice–maize–cowpea cropping system that could cut down soil carbon dioxide (CO₂) emission, sustain grain yield, and maintain better soil quality in tropical low land rice ecology soil respiration in terms of CO₂ emission, labile carbon (C) pools, water-stable aggregate C fractions, and enzymatic activities were investigated in a sandy clay loam soil. Soil respiration is the major pathway of gaseous C efflux from terrestrial systems and acts as an important index of ecosystem functioning. The CO₂–C emissions were quantified in between plants and rows throughout the year in rice–maize–cowpea cropping sequence both under conventional tillage (CT) and minimum tillage (MT) practices along with soil moisture and temperature. The CO₂–C emissions, as a whole, were 24 % higher in between plants than in rows, and were in the range of 23.4–78.1, 37.1–128.1, and 28.6–101.2 mg m^?2 h^?1 under CT and 10.7–60.3, 17.3–99.1, and 17.2–79.1 mg m^?2 h^?1 under MT in rice, maize, and cowpea, respectively. The CO₂–C emission was found highest under maize (44 %) followed by rice (33 %) and cowpea (23 %) irrespective of CT and MT practices. In CT system, the CO₂–C emission increased significantly by 37.1 % with respect to MT on cumulative annual basis including fallow. The CO₂–C emission per unit yield was at par in rice and cowpea signifying the beneficial effect of MT in maintaining soil quality and reduction of CO₂ emission. The microbial biomass C (MBC), readily mineralizable C (RMC), water-soluble C (WSC), and permanganate-oxidizable C (PMOC) were 19.4, 20.4, 39.5, and 15.1 % higher under MT than CT. The C contents in soil aggregate fraction were significantly higher in MT than CT. Soil enzymatic activities like, dehydrogenase, fluorescein diacetate, and β-glucosidase were significantly higher by 13.8, 15.4, and 27.4 % under MT compared to CT. The soil labile C pools, enzymatic activities, and heterotrophic microbial populations were in the order of maize?>?cowpea?>?rice, irrespective of the tillage treatments. Environmental sustainability point of view, minimum tillage practices in rice–maize–cowpea cropping system in tropical low land soil could be adopted to minimize CO₂–C emission, sustain yield, and maintain soil health.     

Monochlorobenzene Marine Risk Assessment with Special Reference to the Osparcom Region: North Sea

This risk assessment on monochlorobenzene was carried out for the marine environment, following methodology given in the EU risk assessment Regulation (1488/94) and Guidance Document of the EU New and Existing Substances Regulation (TGD, 1996). Data from analytical monitoring programmes in large rivers and estuaries in the North Sea area were collected and evaluated for effects and environmental concentrations. Risk is indicated by the ratio of predicted environmental concentration (PEC) to predicted no-effect concentration (PNEC) for the marine aquatic environment. In total, 27 data for fish, 24 data for invertebrates and 13 data for algae were evaluated. Acute and chronic toxicity studies were taken into account and appropriate assessment factors used to define a final PNEC value of 32 micro/l. Recent monitoring data indicate that monochlorobenzene levels in surface waters are below determination limits of 0.1, 0.2, 0.5 microg/l used in monitoring programs. Assuming that half of the lowest determination (0.1 microg/l) is typical, a PEC of 0.05 microg/l was derived. A worst case of 0.5 microg/l is assumed. PEC/PNEC ratios give safety factors of 60 to over 500, taking no account of dilution in the sea. Monochlorobenzene is not a 'toxic, persistent and liable to bioaccumulate' substance sensu the Oslo and Paris Conventions for the Prevention of Marine Pollution (OSPAR-DYNAMEC) criteria. Environmental fate and effects data indicate that current use of monochlorobenzene poses no unacceptable risk to the aquatic environment.     

Use of Biotic Community Structure as a Measure of Ecological Degradation

The benthic macroinvertebrate communities of two lotic aquatic habitats,namely,the Churni River(C-R)and the Jalangi River(J-R)were compared in this study.One lotic aquatic system(C-R)was polluted by organic pollutants due to discharge of unprocessed sewage water,while the other(J-R)was not affected by such pollution.Evaluations of various physico-chemical properties of water,sediment and different macroinvertebrate communities of the two tropical lotic systems were done in a period from January,2002 to December,2003.A long term temporal change in the macroinvertebrate communities was recorded due to increase in sediment rH value.Sediment redox potential affected by the anthropogenic activities was found to be an important factor for alteration of macroinvertebrate communities in these aquatic ecosystems.A positive correlation has been established between rH and Margalef index in this study.Potassium and the total count of coliform bacteria in water showed significantly higher values for the polluted Churni River than those for the Jalangi River.Fig 3,Tab 4,Ref 34     

Characterizing Storm Hydrograph Rise and Fall Dynamics With Stream Stage Data1

Abstract: Storm‐flow transients (i.e., hydrograph rise and fall dynamics) may represent an important aspect of understanding streamflow dynamics. However, little is known about how temporal resolution of transient data and climate variability may color these potential indicators of hydrologic pattern or condition. Warm‐season stream stage and rainfall were monitored continuously (5 min) during the 2002 water year in eight tributaries of the Little Miami River (Ohio), which drain 17‐58 km² catchments. Rise rates generated using 5‐min data were different than those generated with mean daily data [calculated with the Indicators of Hydrologic Alteration (IHA) software], though fall rates were similar for fine and coarse temporal data. This result suggests that data with low temporal resolution may not be adequate to fully represent the dynamics of storm rise rates. Conversely, fall rates based on daily stage data (via IHA) were similar to those based on the 5‐min data, and so daily mean data may be appropriate for characterizing fall rates. We next analyzed the possible correlations between rainfall variability and storm‐flow stage dynamics. We derived rise and recession rates from storm stage hydrographs by assuming exponential rise and decay of a runoff peak. We found that raw rise rates (R_raw) were correlated with both the maximum rainfall rate and the time to the centroid of a rain event. We subsequently removed the trend based on these rainfall characteristics, which yielded new representations of rise rates abbreviated as R_rate and R_tcent, respectively, and that had lower variability than the uncorrected (raw) data. Fall rates were found to be independent of rainfall characteristics. Due to the predominant influence of stream hydrology upon aquatic biota and nutrient fluxes, our work suggests that these stage data analysis protocols can refine or otherwise reduce variability in these indices by accounting for relevant factors such as rainfall forcing. These protocols for derivation of transient indices should be tested for their potential to improve correlations between stream hydrology and temporally aligned biotic data and dissolved nutrient fluxes in streams.     

Cultural and individual differences in self‐rating behavior: an extension and refinement of the cultural relativity hypothesis

This study examined the relationships between culture, individual attributes, and self‐rating behavior among 1,786 university students in Canada, Hong Kong, Taiwan, mainland China, and Japan, and in doing so extended and refined the cultural relativity hypothesis. It explored the difference between vertical and horizontal individualists in self‐rating behavior, and examined the mediating effects of two individual attributes, self‐enhancement propensity and general self‐efficacy in the relationship between individualism and self‐rating behavior. The results confirmed that individualism is the cultural driver for self‐rating leniency, and that the individual‐level assessment of individualism is a stronger predictor of self‐rating leniency than are culture‐level differences. Vertical individualism was found to be positively related to self‐enhancement propensity, which in turn was positively related to self‐rating. Whereas, horizontal individualism was positively related to general self‐efficacy, which in turn had a positive relationship with self‐rating. We discuss the implications of the results for academic research and practical management. Copyright © 2006 John Wiley & Sons, Ltd.     

Long term changes in atmospheric N and S throughfall deposition and effects on soil solution chemistry in a Scots pine forest in the Netherlands

In a Scots pine forest the throughfall deposition and the chemical composition of the soil solution was monitored since 1984. (Inter)national legislation measures led to a reduction of the deposition of nitrogen and sulphur. The deposition of sulphur has decreased by approximately 65%. The total mineral-nitrogen deposition has decreased by ca. 25%, which is mainly due to a reduction in ammonium-N deposition (−40%), since nitrate-N deposition has increased (+50%). The nitrogen concentration in the upper mineral soil solution at 10 cm depth has decreased, leading to an improved nutritional balance, which may result in improved tree vitality. In the drainage water at 90 cm depth the fluxes of NO₃⁻ and SO₄²⁻ have decreased, resulting in a reduced leeching of accompanying base cations, thus preserving nutrients in the ecosystem. It may take still several years, however, before this will meet the prerequisite of a sustainable ecosystem.     

The impact of the 2004 tsunami on coastal Thai communities: assessing adaptive capacity

The suddenness and scale of the 26 December 2004 tsunami and the challenges posed to affected communities highlighted the benefits of their members having a capacity to confront and adapt to the consequences of such a disaster. Research into adaptive capacity or resilience has been conducted almost exclusively with Western populations. This paper describes an exploratory study of the potential of a measure of collective efficacy developed for Western populations to predict the capacity of members of a collective society, Thai citizens affected by the 2004 tsunami, to confront effectively the recovery demands associated with this disaster. Following a demonstration that this measure could predict adaptive capacity, the role of religious affiliation, ethnicity and place of residence in sustaining collective efficacy is discussed. The implications of the findings for future research on, and intervention to develop, adaptive capacity among Thai citizens in particular and collectivist societies in general are discussed.     

Photodegradation of Oryzalin in aqueous isopropanol and acetonitrile

The phototransformation of Oryzalin was studied under UV light (λ_max ≥ 290 nm) and sunlight (λ_max ≥ 250 nm) in aqueous isopropanol and acetonitrile solution in absence and presence of TiO₂ as sensitizer. The rate of photodegradation of Oryzalin in different solvent system followed first-order kinetics, and calculated half-lives were found to be in the range of 23.52-53.75 h for UV light and 41.23-61.43 h for sunlight. From this study, total 12 photoproducts were identified and characterized on the basis of column chromatography and Q-Tof micromass spectral data. The plausible mechanism of phototransformation involved was hydrolysis, breaking of sulfonic bond, and loss of amino and sulfonic acid group.     

Five reasons why it is difficult to talk to Australian farmers about the impacts of,and their adaptation to,climate change

Some recent funding programmes in Australia on climate adaptation have expected active engagement with farmers in research projects. Based on our direct experience with 30 farmers and their advisors, we list five reasons why it is difficult to gain traction with farmers in discussing the likely impacts of climate change on their farms and the possible adaptation options they should be considering in preparation for a future changed climate. The reasons concern the slow and uncertain trajectory for changes in climate relative to the time horizon for farm decision-making, when set against short-term fluctuations in weather, prices, costs and government policy. Farmers have optimism for ongoing technological progress keeping abreast of any negative impacts of climate on their production. As one moves from incremental to transformational adaptation options, biophysical research has less to offer because decisions become based more on business structure, portfolio management, off-farm investments and geographical diversification. Some farmers also doubt the intentions of climate change researchers and are wary of anything they may have to offer. We propose there is an actionable decision space where agricultural science and economics can contribute to meaningful analysis of impacts and adaptation to climate change by farmers. This will involve emphasising the principles of farm management rather than defining optimal farm plans; the use of scenario planning to explore possible futures in a turbulent environment for farming; a focus on short-term adjustments as a path to longer term adaptation; re-gaining the trust of some farmers towards climate change scientists through better communication strategies; and understanding the linkages between adaptation options and enabling factors and technologies.