Discovery of a geomorphological analog to Martian araneiforms in the Qaidam Basin, Tibetan Plateau

Araneiforms are spider-like ground patterns that are widespread in the southern polar regions of Mars.A gas erosion process driven by the seasonal sublimation of CO_(2) ice was proposed as an explanation for their formation,which cannot occur on Earth due to the high climatic temperature.In this study,we propose an alternative mechanism that attrib-utes the araneiform formation to the erosion of upwelling salt water from the subsurface,relying on the identification of the first terrestrial analog found in a playa of the Qaidam Basin on the northern Tibetan Plateau.Morphological analysis indicates that the structures in the Qaidam Basin have fractal features comparable to araneiforms on Mars.A numerical model is developed to investigate the araneiform formation driven by the water-diffusion mechanism.The simulation res-ults indicate that the water-diffusion process,under varying ground conditions,may be responsible for the diverse aranei-form morphologies observed on both Earth and Mars.Our numerical simulations also demonstrate that the orientations of the saltwater diffusion networks are controlled by pre-existing polygonal cracks,which is consistent with observations of araneiforms on Mars and Earth.Our study thus suggests that a saltwater-related origin of the araneiform is possible and has significant implications for water searches on Mars.

Prediction of rockburst classification using Random Forest

The method of Random Forest （RF） was used to classify whether rockburst will happen and the intensity of rockburst in the underground rock projects. Some main control factors of rockburst, such as the values of in-situ stresses, uniaxial compressive strength and tensile strength of rock, and the elastic energy index of rock, were selected in the analysis. The traditional indicators were summarized and divided into indexes I and 1I. Random Forest model and criterion were obtained through training 36 sets of rockburst samples which come from underground rock projects in domestic and abroad. Another 10 samples were tested and evaluated with the model. The evaluated results agree well with the practical records. Comparing the results of support vector machine （SVM） method, and artificial neural network （ANN） method with random forest method, the corresponding misjudgment ratios are 10%, 20%, and 0, respectively. The misjudgment ratio using index I is smaller than that using index II. It is suggested that using the index I and RF model can accurately classify rockburst grade.

Predicting pillar stability for underground mine using Fisher discriminant analysis and SVM methods

The purpose of this study is to apply some statistical and soft computing methods such as Fisher discriminant analysis （FDA） and support vector machines （SVMs） methodology to the determination of pillar stability for underground mines selected from various coal and stone mines by using some index and mechanical properties, including the width, the height, the ratio of the pillar width to its height, the uniaxial compressive strength of the rock and pillar stress. The study includes four main stages： sampling, testing, modeling and assessment of the model performances. During the modeling stage, two pillar stability prediction models were investigated with FDA and SVMs methodology based on the statistical learning theory. After using 40 sets of measured data in various mines in the world for training and testing, the model was applied to other 6 data for validating the trained proposed models. The prediction results of SVMs were compared with those of FDA as well as the measured field values. The general performance of models developed in this study is close; however, the SVMs exhibit the best performance considering the performance index with the correct classification rate Prs by re-substitution method and Pcv by cross validation method. The results show that the SVMs approach has the potential to be a reliable and practical tool for determination of pillar stability for underground mines.

Time-dependent magnetometric resistivity anomalies of groundwater contamination: Synthetic results from computational hydro-geophysical modeling

We present a forward-modeling investigation of time-dependent ground magnetometric resistivity （MMR） anomalies associated with transient leachate transport in groundwater systems. Numerical geo-electrical models are constructed based on the hydrological simulation results of leachate plumes from a highly conceptualized landfill system and the resultant MMR responses are computed using a modified finite difference software MMR2DFD. Three transmitter configurations （i.e., single source, MMR-TE, and MMR-TM modes） and two hydrological models （i.e., uniform and faulted porous media） are considered. Our forward modeling results for the uniform porous medium indicates that the magnetic field components perpendicular to the dominant current flow contain the most information of the underground targets and the MMR-TE mode is an appropriate configuration for detecting contaminant plumes. The modeling experiments for the faulted porous medium also confirm that the MMR method is capable of mapping and monitoring the extent of contaminant plumes in aroundwater systems.

Cultivation Techniques of Panax notoginseng F.H. Chen under Different Forests

To overcome the issues of high cost and continuous cropping obstacles in facility cultivation of Panax notoginseng_ F. H. Chen, satisfy the market demand, save the production cost, improve the utilization rate of forest land, increase the in-come of forest farmers and protect the ecological environment, the cultivation tech-niques of high-quality P. notoginseng seedlings from Wenshan, Yunnan under four kinds of forests （walnut forest, China fir forest, grape forest and kiwi forest） were in-vestigated in this study. The results showed that the height growth, crown diameter, survival rate and 3-year-old tuber weight of P. notoginseng_under walnut forest were higher than those under the other three kinds of forests; the height growth, crown diameter, survival rate and 3-year-old tuber weight of P. notoginseng under China fir forest were higher than those under grape forest and kiwi forest; and the crown di-ameter and survival rate under grape forest were higher, and the height growth and tuber weight under grape forest were lower than those under kiwi forest. Walnut is a broad-leaved deciduous tree species, so large-scale cultivation of P. notoginseng_should be conducted under broadleaf deciduous forest with canopy density around 0.8, taking advantage of the cool environment and rich humus layer under forest. This cultivation technology could save labor, shade, fertilizer and other costs, and accord with the ecological habit and the growth rules of P. notoginseng, thus im-proving yield and achieving high economic benefit.

Rhizome Elongation Growth of Umbrella Bamboo(Fargesia murielae) Seedlings at Its Native Home in Central China

[Objective] The aim was to investigate the rhizome elongation growth of umbrella bamboo （Fargesia murielae） seedlings in China. [Method] The study was conducted in Liangfengya, Shennongjia National Nature Reserve. In the field investigation, six clumps of umbrella bamboo which grow independently were randomly selected and labeled. Rhizome elongation growth parameters, length and diameter of all the ages were measured. The age classes of bamboo rhizome were ascertained by age grade backtracking method. [Result] Field investigation suggested that at seedling phase, rhizome of umbrella bamboo prolonged very quickly under yearly time sequence, following an exponential curve. It indicated that although it was 15 years since the mother population died back, new generation had not been established its stable population yet. [Conclusion] Studying elongation regulation of umbrella bamboo may provide the theory understanding of life cycle of this long lived bamboo species.

Review on the Development of Oil and Gas Flow in Underground Porous Media

Through reviewing the flow theory’s birth and development history in underground porous media and contrasting the mechanics of underground fluids and mechanics of viscous fluids, this paper points out the main factors, which affect the development of the theory on oil and gas porous flow. The development law and development route of the mechanics of fluids in porous media are also summarized in this paper.

Growth Strategy of Seagrass Thalassia hemprichii in Xincun Bay near Hainan Island of China

A compilation of data on biomass and growth allowed an examination of the intraspecific plasticity in Tha/assia hemprichii which played key roles to develop site-specific growth strategies for this species in Xincun Bay. The results showed the difference in rhizome elongation rates which explained most of the variation of biomass and growth within species. The seagrass T. hempdchii in Xincun Bay adjusted its vertical and horizontal rhizome elongation rates alternatively in response to light level and temperature changes, resulting in the variation of shoot densities and above biomass in return. The vertical and horizontal rhizomes elongated at rates of 2.38 and 24.4 cm yr1 in summer while 1.87 and 29.2 cm yr^-1 in winter respectively. The shoot density ranged from 822 to 941 shoots m^2 with a peak in summer and a trough in winter which was similar to that of biomass. The growth strategy enabled T. hempdchii to minimize the negative effects of desiccation in summer as well as light reduction in winter.

Analysis of the Groundwater System Change and Driving Factors in Songnen Plain in Jilin Province

[Objective] The aim was to provide theoretical basis for the study of underground water dynamic changes in Songnen Plain in Jilin Province.[Method] The dynamic changes and driving factors for the underground water in Songnen Plain in Jilin Province was expounded.[Result] Since 1960s,the temperature in the Songnen Plain in Jilin Province increased gradually.The average temperature increased 2℃;precipitation reduced gradually.Especially,the trend of precipitation reduction in west area was more distinct;in the meantime,the development of underground water augmented gradually and reached 2 800 million m3 in 2008.Driven by many factors,regional underground water level had distinct changes.Potential water position reduced greatly in northwest fan-shaped area.The one in other places were stable and even increased in certain parts;confined water position decreased quickly in general and it increased in certain parts.[Conclusion] The general deterioration trend of underground water environment was inevitable.But,the deterioration process can be eased through scientific planning and regional underground water resources so as to realize sustainable utilization of regional underground water resources.

Effect of Irrigation on Groundwater Dynamic Change in the Typical Irrigated Area of Qinghai Province

Under the influence of the natural and human factors, water table of irri- gated area Changes frequently, but it is mainly affected by irrigation water infiltration replenishment during the irrigation. 5 groundwater observation wells were constructed in experimental plot of the Daxia irrigated area to carry out the experiment of the effect of irrigation on groundwater dynamic change in this research. The results showed that the groundwater stage dynarnic change rule of spring and seedling irri- gation stage in the typical plot was fit to the hydrological geology condition of grade- I terrace of Huangshui river valley. On the whole, lateral canal water direction formed a line effect. The No. 1 and No. 2 observation well were the closest to the lateral canal, which received more supplies, and the water level was the highest; the No, 3 observation well took the second place; The No. 4 and No. 5 observation well accepted least supplies, and the water level was the lowest. The rangeability of water table of spring irrigation period was significantly higher than that of seedling irrigation period, this is mainly due to the difference value of intake water volume and drainage water volume of spring irrigation phase was significantly higher than the seedling irrigation phase.

Distribution of ice thickness and subglacial topography of the "Chinese Wall" around Kunlun Station,East Antarctica

As fundamental parameters of the Antarctic Ice Sheet,ice thickness and subglacial topography are critical factors for studying the basal conditions and mass balance in Antarctica.During CHINARE 24（the 24 th Chinese National Antarctic Research Expedition,2007/08）,the research team used a deep ice-penetrating radar system to measure the ice thickness and subglacial topography of the ＂Chinese Wall＂ around Kunlun Station,East Antarctica.Preliminary results show that the ice thickness varies mostly from 1600 m to 2800 m along the ＂Chinese Wall＂,with the thickest ice being 3444 m,and the thinnest ice 1255 m.The average bedrock elevation is 1722 m,while the minimum is just 604 m.Compared with the northern side of the ice divide,the ice thickness is a little greater and the subglacial topography lower on the southern side,which is also characterized by four deep valleys.We found no basal freeze-on ice in the Gamburtsev Subglacial Mountains area,subglacial lakes,or water bodies along the ＂Chinese Wall＂.Ice thickness and subglacial topography data extracted from the Bedmap 2 database along the ＂Chinese Wall＂ are consistent with our results,but their resolution and accuracy are very limited in areas where the bedrock fluctuates intensely.The distribution of ice thickness and subglacial topography detected by ice-penetrating radar clarifies the features of the ice sheet in this ＂inaccessible＂ region.These results will help to advance the study of ice sheet dynamics and the determination of future locations of the GSM＇s geological and deep ice core drilling sites in the Dome A region.

Experimental Study on the Utilization of Shallow Groundwater for Spring Wheat

[Objective]The paper aimed to study effect of shallow groundwater at different depths on crop water requirement and crop evaporation in spring wheat field.[Method]Five treatments of shallow groundwater table at different depth were designed to do evaporation experiment for spring wheat in 2008-2009.[Result]The groundwater at different depths had great impact on crop growth and field evaporation;its supply accounted for 0-52% of actual evapotranspiration.Atmospheric evaporation and crop rooting depth were the major factors to affect the uptake of groundwater at shallow table,and the supply of deep groundwater was controlled by groundwater table.[Conclusion]The study reveled the pattern of evapotranspiration of spring wheat and evaporation of shallow groundwater at different depth,in order to supply basis for the rational and effective utilization of shallow groundwater as well as optimization of the irrigation scheduling for spring wheat.

Influences of Surface Drip Irrigation on the Growth, Yield and Quality of Several New Species of Guitang Sugarcane

[Objective] This paper discussed the influences of surface drip irrigation on the growth, yield and quality of several new species of Guitang, in order to provide references for the promotion of new species and high-yield cultivation. [Method] One species is planted in each region, and there were two controls dripping technology or no-dripping technology in each region. [Results] The average yield of dripping-pro- cessed land was 115.91 t/hm2, which was 19.73 t/hm2 higher than the control. The maximum output was GT31, followed by GT34. The output of all Guitang new species was higher than the control ROC22. The average sucrose of dripped sug- arcane was 14.68%, which was 0.19% less than the control of 14.83%. The drip- ping technology was economically beneficial, rising by 15.2% compared with the control. The highest dripping efficiency was GT31, while the lowest one was ROC22. The increasing ratios of drip irrigation efficiency of the tested new Guitang species were higher than ROC22. [Conclusions] Under the drip irrigation condition, the sugarcane yield was extremely higher than the control of non-dripping irrigation, and the economic efficiency was significant. However, the sugar in the sugarcane declined slightly. The sensitivity of several new Guitang species to water was higher than the control ROC22.

Nitrate Nitrogen Content Characteristics in Groundwater of Typical Planting Areas in Liao River Basin

The contents of nitrate nitrogen（NO-3-N） in underground water from typical planting areas in Liao river basin were analyzed, so as to provide theoretical basis for rational fertilization and effectively prevent the NO-3-N content from exceeding standard. The results showed that difference of the contents of NO-3-N in groundwater from different typical planting areas was significant. The highest content of NO-3-N in underground water was 37.4 mg/L from flower-growing region, then 22. 3 mg/L from maize-growing region, 21.9 mg/L from vegetable-growing region, and the lowest content of NO-3-N in underground water was 19.2 mg/L from rice-growing region. Except rice-growing region, the contents of NO-3-N in underground water of the samples in all planting areas were exceeding standard limit; potential health risk still existed in rice-growing region. Accordingly 12.5%-87.5%, 9.4%-75.5%, 17.9%-58.9% and 21.4%-96.0% of the samples were exceeding standard limit in maize growing region, rice-growing region, vegetable-growing region and flower-growing region. The contents of NO-3-N in under-groundwater before the rainy season was higher than that of NO-3-N in under-groundwater after the rainy season at the same depth of the well.

Analysis on the Hydrochemical Characteristics of Groundwater and the Formation Reason in Wadi Bay Area of Libya

[Objective] The research aimed to analyze the formation reason of groundwater hydrochemical characteristics in the dry valley area of Wadi Bay of Libya and provide the scientific basis for the reasonable development utilization and the environmental protection of groundwater.[Method] Took Wadi Bay area（dry valley）of Libya as the example,Piper trilinear graphic representation method,the descriptive statistics,the ion ratio coefficient method and the isotope evidence were used to systematically study the special hydrochemical characteristics of shallow groundwater in the arid climate condition in Wadi Bay area of Libya.[Result] The salt content of groundwater in the area was very high,and TDS was during 3.2-8.4 g/L.The main groundwater type was Cl·SO4-Na·Ca,then was Cl·SO4-Na·Ca·Mg.The concentrations of Cl-,Na＋ and SO2-4,etc.in the groundwater in 70 km from the sea had the remarkable variation,but the concentrations of Mn2＋,Ba2＋,Si2＋,NH＋4 and NO-3 didn＇t have the same variation phenomenon.[Conclusion] The hydrochemical characteristics of shallow groundwater didn＇t relate to the dissolution infiltration reaction,the evaporation concentration effect and human activities.The major cause was the mixing effect of salt and fresh water in the invasion process of seawater.

Hybrid FEM-BEM for simulation of electromagnetic response

A finite element method with boundary element method (FEM-BEM) is presented for computing electromagnetic induction. The features of an edge element method including the volume and surface edge element method are investigated in depth. Surface basis functions of edge elements to an arbitrary shape of target are derived according to the geometrical property of basis functions and applied to discretize the surface integral equation for 3-D general targets. The proposed model is presented to compute resonant frequencies and surface current of underground unexplored ordnance (UXO), and then the electromagnetic responses of single target with different frequencies and positions of sensor are simulated and results are validated by experiments.

Key parameter optimization and analysis of stochastic seismic inversion

Stochastic seismic inversion is the combination of geostatistics and seismic inversion technology which integrates information from seismic records, well logs, and geostatistics into a posterior probability density function （PDF） of subsurface models. The Markov chain Monte Carlo （MCMC） method is used to sample the posterior PDF and the subsurface model characteristics can be inferred by analyzing a set of the posterior PDF samples. In this paper, we first introduce the stochastic seismic inversion theory, discuss and analyze the four key parameters： seismic data signal-to-noise ratio （S/N）, variogram, the posterior PDF sample number, and well density, and propose the optimum selection of these parameters. The analysis results show that seismic data S/N adjusts the compromise between the influence of the seismic data and geostatistics on the inversion results, the variogram controls the smoothness of the inversion results, the posterior PDF sample number determines the reliability of the statistical characteristics derived from the samples, and well density influences the inversion uncertainty. Finally, the comparison between the stochastic seismic inversion and the deterministic model based seismic inversion indicates that the stochastic seismic inversion can provide more reliable information of the subsurface character.

Research Progress of Soil Loss in Karst Areas under the Dual Structure of Southwest China

The research progress of soil loss under the dual structure of southwest karst is systematically studied. The results show that the research of the soil erosion in karst mountainous area started late, and the basic research is lagging. Most of the existing research results focus on the present situation, causes and control measures of surface erosion. The view of underground soil loss in the context of karst diploid structure has been recognized by most scholars. However, limited to the research methods and the lack of observational data, the way of underground soil loss, the amount of loss and its harm are still unclear. Therefore, seeking the necessary technical means to carry out the necessary field observation from the way and process of loss is the focus of the study of soil loss under karst structure in the future.

Tomato Root Response to Subsurface Drip Irrigation

Four depth treatments of subsurface drip irrigation pipes were designated as 1) at 20,2) 30 and 3) 40 cm depths all with a drip-proof flumes underneath,and 4) at 30 cm without a drip-proof flume to investigate the responses of a tomato root system to different technical parameters of subsurface drip irrigation in a glass greenhouse,to evaluate tomato growth as affected by subsurface drip irrigation,and to develop an integrated subsurface drip irrigation method for optimal tomato yield and water use in a glass greenhouse. Tomato seedlings were planted above the subsurface drip irrigation pipe. Most of the tomato roots in treatment 1 were found in the top 0-20 cm soil depth with weak root activity but with yield and water use efficiency (WUE) significantly less (P ---- 0.05) than treatment 2; root activity and tomato yield were significantly higher (P = 0.05) with treatment 3 compared to treatment 1; and with treatment 2 the tomato roots and shoots grew harmoniously with root activity,nutrient uptake,tomato yield and WUE significantly higher (P= 0.05) or as high as the other treatments. These findings suggested that subsurface drip irrigation with pipes at 30 cm depth with a drip-proof flume placed underneath was best for tomato production in greenhouses. In addition,the irrigation interval should be about 7-8 days and the irrigation rate should be set to 225 m3 ha-1 per event.

Effects of Soil Properties on Phosphorus Subsurface Migration in Sandy Soils

The soil factors influencing the potential migration of dissolved and particulate phosphorus(P) from structurally-weak sandy subsoils were evaluated by means of soil column leaching experiments. Soil colloids were extracted from two types of soils to make the colloid-bound forms of P solution. Eight sandy soils with diverse properties were collected for packing soil columns. The effects of influent solutions varying in concentrations of colloids,P,and electrolyte,on the transport of P and quality of leachates were characterized. P migration in the soils was soil property-dependent. High soil electrical conductivity values retarded the mobility of colloids and transportability of colloid-associated P(particulate P) . Soil electrical conductivity was negatively correlated with colloids and reactive particulate P(RPP) concentrations in the leachates,whereas,the total reactive P(TRP) and dissolved reactive P(DRP) concentrations in the leachates were mainly controlled by the P adsorption capacity and the P levels in the subsoil. The reactive particulate P in the leachates was positively correlated with the colloidal concentration. Increased colloidal concentration in the influent could significantly increase the colloidal concentration in the leachates. Elevated P concentration in the influent had little effect on P recovery in the leachates,but it resulted in significant increases in the absolute P concentration in the leachates.