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91.
Maize is grown by millions of smallholder farmers in South Asia (SA) under diverse environments. The crop is grown in different seasons in a year with varying exposure to weather extremes, including high temperatures at critical growth stages which are expected to increase with climate change. This study assesses the impact of current and future heat stress on maize and the benefit of heat-tolerant varieties in SA. Annual mean maximum temperatures may increase by 1.4–1.8 °C in 2030 and 2.1–2.6 °C in 2050, with large monthly, seasonal, and spatial variations across SA. The extent of heat stressed areas in SA could increase by up to 12 % in 2030 and 21 % in 2050 relative to the baseline. The impact of heat stress and the benefit from heat-tolerant varieties vary with the level of temperature increase and planting season. At a regional scale, climate change would reduce rainfed maize yield by an average of 3.3–6.4 % in 2030 and 5.2–12.2 % in 2050 and irrigated yield by 3–8 % in 2030 and 5–14 % in 2050 if current varieties were grown under the future climate. Under projected climate, heat-tolerant varieties could minimize yield loss (relative to current maize varieties) by up to 36 and 93 % in 2030 and 33 and 86 % in 2050 under rainfed and irrigated conditions, respectively. Heat-tolerant maize varieties, therefore, have the potential to shield maize farmers from severe yield loss due to heat stress and help them adapt to climate change impacts.  相似文献   
92.
The paper describes the results of research on the applicability of the ground penetrating radar (GPR) method for remote sensing and monitoring of the underground coal gasification (UCG) processes. The gasification of coal in a bed entails various technological problems and poses risks to the environment. Therefore, in parallel with research on coal gasification technologies, it is necessary to develop techniques for remote sensing of the process environment. One such technique may be the radar method, which allows imaging of regions of mass loss (voids, fissures) in coal during and after carrying out a gasification process in the bed. The paper describes two research experiments. The first one was carried out on a large-scale model constructed on the surface. It simulated a coal seam in natural geological conditions. A second experiment was performed in a shallow coal deposit maintained in a disused mine and kept accessible for research purposes. Tests performed in the laboratory and in situ conditions showed that the method provides valuable data for assessing and monitoring gasification surfaces in the UCG processes. The advantage of the GPR method is its high resolution and the possibility of determining the spatial shape of various zones and forms created in the coal by the gasification process.  相似文献   
93.
The results of geophysical studies conducted with selected electrical and electromagnetic methods in the Kondratowa Valley in the Tatra Mountains (the Carpathian Mountains, Poland) are presented in the article. The surveys were performed with the following methods: electrical resistivity tomography (ERT), georadar (GPR) and conductivity meter (CM). The objective of the noninvasive geophysical measurements was to determine the thickness of the Quaternary postglacial sediments that fill the bottom of the valley and to designate the accumulation of boulders deposited on Quaternary sediments. The results of ERT surveys conducted along the axis of the valley allowed to determine the changeability of the thickness of the postglacial sediments and allowed to designate a few areas of occurrence of boulders. The ERT, GPR and CM surveys conducted across the valley allowed to designate with high accuracy the thickness of the accumulation of boulders sliding down the valley bottom from the couloirs surrounding the valley.  相似文献   
94.
Piping has been recognized as an important geomorphic, soil erosion and hydrologic process. It seems that it is far more widespread than it has often been supposed. However, our knowledge about piping dynamics and its quantification currently relies on a limited number of data for mainly loess‐derived areas and marl badlands. Therefore, this research aimed to recognize piping dynamics in mid‐altitude mountains under a temperate climate, where piping occurs in Cambisols, not previously considered as piping‐prone soils. It has been expressed by the estimation of erosion rates due to piping and elongation of pipes in the Bere?nica Wy?na catchment in the Bieszczady Mountains, eastern Carpathians (305 ha, 188 collapsed pipes). The research was based on the monitoring of selected piping systems (1971–1974, 2013–2016). Changes in soil loss vary significantly between different years (up to 27.36 t ha?1 yr?1), as well as between the mean short‐term erosion rate (up to 13.10 t ha?1 yr?1), and the long‐term (45 years) mean of 1.34 t ha?1 yr?1. The elongation of pipes also differs, from no changes to 36 m during one year. The mean total soil loss is 48.8 t ha?1 in plots, whereas in the whole studied catchment it is 2.0 t ha?1. Hence, piping is both spatially and temporally dependent. The magnitude of piping in the study area is at least three orders of magnitude higher than surface erosion rates (i.e. sheet and rill erosion) under similar land use (grasslands), and it is comparable to the magnitude of surface soil erosion on arable lands. It means that piping constitutes a significant environmental problem and, wherever it occurs, it is an important, or even the main, sediment source. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   
95.
Studia Geophysica et Geodaetica - A fundamental tectonic boundary between the Precambrian East European Craton (EEC) and the younger Phanerozoic mountain belts of Europe runs through Poland....  相似文献   
96.
The goal of the paper was to determine the activity of 137Cs and 40K radionuclides as well as heavy metals Zn, Cr, Pb in soil samples taken from the Tatra National Park in the south of Poland. The samples were obtained as cores (10 cm in diameter) from the top 10-cm layer of the soil. Each sample was divided into three subsamples (a, b and c), where a was the subsample closest to the surface and c was the deepest one. Activity of the radionuclides was determined by means of gamma spectrometry, while analysis of heavy metals was performed (after microwave digestion) using atomic absorption spectrometry technique. The highest activity of cesium-137 was detected (5112 ± 120 Bq kg?1) in the “a” layer of the core with the peak concentration of cesium-137 (14,452 ± 278 Bq m?2) in the whole soil core. The highest detected concentration of heavy metals was: Zn—52.8 ± 4.4 mg kg?1, Pb—260.1 ± 9.4 mg kg?1, Cr—52.8 ± 4.4 mg kg?1, respectively. Cluster analysis and principal component analysis were used to examine the obtained data. Application of statistical analysis tools allowed specifying the interdependencies between the examined variables.  相似文献   
97.
Study was carried out to compare the effect of the degree of contamination of soil with copper on the soil enzyme activity, depending on the type of chemical compound with which a metal reaches the soil and on the method of soil use. An effect of increasing doses of copper on growth and the development of spring barley has been studied. The study was carried out as a pot experiment on two types of soil: loamy sand and light loam. Copper was introduced to soil as copper(II) sulphate(VI) and copper(II) chloride at four doses: 150, 300, 450 and 600 mg Cu2+ kg?1 d.m. of soil. Soil without copper was used as a control sample. The experiment showed that contamination of soil with copper applied as CuCl2 and CuSO4·5H2O upset the homeostasis of soil. Dehydrogenases and urease were the most sensitive to contamination of soil with Cu2+, both as copper(II) chloride and as copper(II) sulphate(VI), and acid phosphatase and alkaline phosphatase were the least sensitive. Greater changes in enzymatic activity were observed in loamy sand than in light loam. The differences in the impact of copper(II) sulphate(VI) and copper(II) chloride on the soil microbiome were relatively small, because mean ED50 for copper(II) chloride was 341 mg Cu2+ kg?1 d.m. of soil, and for copper(II) sulphate(VI) it was 364 mg Cu2+ kg?1 d.m. of soil. This inhibitory effect of copper persisted throughout the period of the experiment. The sensitivity of spring barley to copper compounds was lower than the enzymes under study.  相似文献   
98.
Basic knowledge of the characteristics of copper-bearing rock such as dolomite is essential to locate those areas of the deposit which have different structural and textural properties. Those regions can be important in terms of the assessment of the possibilities of gas accumulating in them as well as in terms of gasogeodynamic hazard. To better understand those threats, it is necessary to locate, monitor and analyse those areas in detail. This article characterises the structural and textural parameters of dolomite from the Polkowice–Sieroszowice copper mine in Poland. The study involved five samples from various areas of the mine. A number of research methods were selected. Reflected and transmitted light microscopy (MS), computer microtomography (Micro-CT), gas adsorption porosimetry (LPNA), mercury porosimetry (MIP), helium and quasi-fluid pycnometry (Pycno. He, DryFlo). Each of the methods examined a different scope of the pore size, which enabled to achieve a full view of the porous nature of those rocks. We determined their porosity (open, closed, total), surface area as well as mean size and volume of the pores. Also, we studied the character and the pore size distribution from a few nm to a few mm. Comprehensive dolomite properties analyses showed that these rocks are characterised by high structural variability. They have mesopores and macropores but few micropores. The analyses presented in this paper are determined by a large petrographic diversity of the deposits containing dolomite. This article is an example of a comprehensive approach to the rock analysis in copper ore mines.  相似文献   
99.
The purpose of this paper is twofold. First, we demonstrate that the asymmetry between El Niño and La Niña events recorded in sea level variation occurs only during extreme episodes of El Niño/Southern Oscillation. Second, we explain that the asymmetry is controlled by certain regular cycles which have time-variable amplitudes. Gridded maps of sea level anomaly that form a spatial-temporal time series (spatial resolution: 1° × 1°, sampling interval: 1 week) spanning the time interval from 14/10/1993 to 18/04/2012 were used. We examined those time series and found that certain regular harmonic signals (periods: 365, 182, 120, 90 and 62 days) are dominant terms of their temporal variability. By subtracting those oscillations from sea level anomaly data, residuals were determined. Using skewness and kurtosis as measures of asymmetry and nonlinearity — after adopting 10-year moving window — we found that the extreme El Niño 1997/1998 has been a dominant driving force of the asymmetry and nonlinearity of El Niño/Southern Oscillation since the end of 1993. In order to detect residual signals that are responsible for the asymmetry, we applied the Fourier Transform Band Pass Filter and found that there are two important oscillations remaining in the residual sea level anomaly data, i.e. the annual and semiannual ones with time-varying amplitudes. We hypothesize that temporarily uneven amplitudes have meaningful impact on the aforementioned asymmetry.  相似文献   
100.
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