Shiyang River Research Articles

Parameter sensitivity analysis of SWAT model for streamflow simulation with multisource precipitation datasets

Abstract Streamflow in the Shiyang River basin is numerically investigated based on the soil and water assessment tool (SWAT). The interpolation precipitation datasets of GSI, multisource satellite and reanalysis precipitation datasets including TRMM, CMDF, CFSR, CHIRPS and PGF are specially applied as the inputs for SWAT model, and the sensitivities of model parameters, as well as streamflow prediction uncertainties, are discussed via the sequential uncertainty fitting procedure (SUFI-2). Results indicate that streamflow simulation can be effectively improved by downscaling the precipitation datasets. The sensitivities of model parameters vary significantly with respect to different precipitation datasets and sub-basins. CN2 (initial SCS runoff curve number for moisture condition II) and SMTMP (base temperature of snow melt) are found to be the most sensitive parameters, which implies that the generations of surface runoff and snowmelt are extremely crucial for streamflow in this basin. Moreover, the uncertainty analysis of streamflow prediction indicates that the performance of simulation can be further improved by parameter optimization. It also demonstrates that the precipitation data from satellite and reanalysis datasets can be applied to streamflow simulation as effective inputs, and the dependences of parameter sensitivities on basin and precipitation dataset are responsible for the variation of simulation performance.

Spatial Heterogeneity of Soil Moisture and Vegetation Cover in Shiyang River Basin, Northwest China

Landsat TM remote sensing images were used to calculate and analysis distribution characteristics of soil moisture and vegetation cover in Shiyang River Basin in 2010. According to the images and reference to the general method, the vegetation index of Shiyang River Basin was divided into bare land, sparse vegetation, moderate vegetation and lush vegetation. Besides, the direct effects of different soil moisture on vegetation cover were also analyzed according to the spatial distribution characteristics of soil water. The results showed that the ecological environment in Shiyang River Basin was further deteriorating in the past, the production capacity of land was decline in the research period.

Spatiotemporal Changes in Evapotranspiration from an Overexploited Water Resources Basin in Arid Northern China and Their Implications for Ecosystem Management

Evapotranspiration (ET), including evaporation from soil and water surfaces and transpiration from vegetation, influences water distribution in the soil-plant-atmosphere continuum, especially in arid areas where water is a key limiting factor. Therefore, understanding the spatiotemporal dynamics of ET, including its two components of soil evaporation (Es) and vegetation transpiration (Ec), can be useful for water resource management and ecological restoration in arid regions. Based on ET data from 2002 to 2012, the spatiotemporal variations in ET were evaluated in the Shiyang River Basin in arid Northwest China. The results showed the following: (1) spatially, ET decreased from upstream of the Qilian Mountains to the middle and downstream, with a mean annual value of 316 mm; (2) temporally, ET showed a single peak curve throughout the year, with the highest value occurring in summer; (3) ET showed a downward trend (from 350 to 265 mm) before 2009 and thereafter increased (from 265 to 345 mm); and (4) water use efficiency, indicated by the ratio of Ec to ET, was low in the cropland, with a mean value of 50.9%. Further analysis indicates that decreases in ET are mainly caused by vegetation decreases; in contrast, ecological restriction measures and strict water resource management policies in the middle reaches of the basin led to ET increases. It is concluded that understanding ET and its two components can elucidate the connections between water and human society.

Assessing the Ecological Effects of Water Transport to a Lake in Arid Regions: A Case Study of Qingtu Lake in Shiyang River Basin, Northwest China.

With the continuous growth of economic water consumption in arid regions, many endorheic rivers and terminal lakes have desiccated. As an important ecological engineering measure, water transport in arid regions has vital ecological significance for protecting the regional ecological environment and delaying desertification. In this study, Qingtu Lake, the terminal lake of Shiyang River, was selected to analyze the ecological effects of water transport by means of remote sensing interpretations and current year field investigations. The results demonstrated that, in July 2018, the water surface had formed and recovered to 5.68 km2. Additionally, Qingtu Lake formed a spatial gradient distribution in groundwater depth. The depth increased in gradient from the waterside to the desert edge. There was a significant increase in the overall regional vegetation coverage, which mainly occurred in the water areas because of the extensive growth in Phragmites australis, which reached 10.54 km2 in area in 2018. Furthermore, the regional vegetation formed a gradient distribution, which transitioned from hygrophytes to xerophytes. This study can provide guidelines for the protection and restoration of lakes in arid regions.

基于空间距离指数的中国西北干旱内陆河流域生态敏感性时空演变特征——以石羊河流域为例

基于空间距离指数的中国西北干旱内陆河流域生态敏感性时空演变特征——以石羊河流域为例

基于CA-Markov模型的石羊河流域生态承载力时空格局预测

PDF HTML阅读 XML下载 导出引用 引用提醒 基于CA-Markov模型的石羊河流域生态承载力时空格局预测 DOI: 10.5846/stxb201711302153 作者: 作者单位: 兰州大学资源环境学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金（41671516，41701623）；中国科学院西北生态环境资源研究院青年人才成长基金；甘肃省软科学专项（1504ZKCA090-1） Spatio-temporal pattern prediction of the biocapacity in the Shiyang River Basin on the basis of the CA-Markov model Author: Affiliation: Lanzhou University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:生态承载力是区域可持续发展的重要物质基础。为了探讨我国干旱区内陆河流域未来生态承载力的时空格局变化，以石羊河流域为研究区，基于该流域1992、2002年和2012年3期Landsat TM遥感影像，选取10个影响生态承载力变化的主要驱动因素，利用元胞自动机-马尔科夫模型（CA-Markov），以土地利用预测为切入点，对该流域2022年的生态承载力时空格局进行了模拟预测。首先基于1992-2002年数据预测了2012年石羊河流域土地利用状况，并与当年实际土地利用状况进行对比和验证，结果显示：Kappa系数为0.7956，说明本文所选用的预测方法预测结果可靠，可以用于该流域土地利用预测；其次，以2012年为起始年，模拟预测了2022年土地利用空间数据，并计算生态承载力时空格局，结果显示：2022年石羊河流域单位面积生态承载力与1992年、2002年和2012年相比整体空间分布格局变化不大，但区域内部变化却呈明显的空间分异特征；1992-2022年流域生态承载力总量以2002年为拐点呈先减少后增加的趋势，其中建设用地的生态承载力增加最为显著；预测可知，较2012年，2022年流域上游山区的林地、中游绿洲的建筑用地生态承载力均增加较快，且呈现较明显的斑块聚集，而中、下游绿洲区耕地、草地生态承载力增、减变化复杂，斑块分布较为离散和破碎；2012-2022年土地利用类型将发生频繁转换，导致流域生态承载力结构组成变化较大，其中未利用地的转出对2022年流域生态承载力的增加贡献突出。研究结果表明自2002年以后，该流域实施的退耕还林还草、关井压田等生态工程已经并将继续对该流域生态效益的提高起到积极的作用。 Abstract:The biocapacity is an important material foundation of regional sustainable development. In order to explore the spatio-temporal pattern of biocapacity in inland rivers, arid China in the future, for a case study of the Shiyang River Basin, using the CA-Markov model as a predication method and choosing 10 main driving factors influencing the biocapacity, we predicted the land use and assessed biocapacity in 2022 based on LandsatTM images in 1992, 2002, and 2012. First of all, by comparing the predicted land use with the actual land use situation in 2012, we got the Kappa coefficient of 0.7956, which showed that the driving factors and the CA-Markov model were reliable for predicting the land use of the basin. Second, based on the model above, we predicted the land use condition and assessed biocapacity in 2022 with the year 2012 as a starting point. The results showed the following:in the Shiyang River Basin as a whole, the distribution pattern of biocapacity per unit area in 2022 will be similar to the situation in 1992, 2002, and 2012; however, there was remarkable spatial heterogeneity within the basin. The total biocapacity of the basin in 1992-2022 has been increasing since the turning point in 2002, and the increase of biocapacity in the built-up area was the most significant part of them. In the comparison with 2012, the biocapacity of the forestland in the mountainous area of the upstream reach and the built-up area in the oasis area of the midstream reach in 2022 should increase faster than other areas of the river basin, and there was a significant patch cohesion. Nonetheless, in the oasis areas of midstream and downstream reaches, the changes of farmland and grassland biocapacity should be complicated and the distribution of the land use patch should be discrete and fragmented. The frequent transition of land use types in 2012-2022 should lead to a large structural change of the biocapacity in the river basin, including an important contribution to the increase of biocapacity supported by the transfer-out area of unused land in 2022. Above all, the results provided a more extensive understanding of the spatio-temporal dynamic and spatial pattern of biocapacity in the Shiyang River Basin. Ecological engineering such as the Grain for Green Project will continue to produce obvious ecological benefits in the future. 参考文献 相似文献 引证文献

基于SPCA和遥感指数的干旱内陆河流域生态脆弱性时空演变及动因分析——以石羊河流域为例

PDF HTML阅读 XML下载 导出引用 引用提醒 基于SPCA和遥感指数的干旱内陆河流域生态脆弱性时空演变及动因分析——以石羊河流域为例 DOI: 10.5846/stxb201805211114 作者: 作者单位: 西北师范大学,西北师范大学,西北师范大学,西北师范大学,西北师范大学,兰州城市学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41861040，41761047）；甘肃省自然科学基金项目（1506RJZA129） Spatio-Temporal evolution and motivation analysis of ecological vulnerability in Arid Inland River Basin based on SPCA and remote sensing index: A case study on the Shiyang River Basin Author: Affiliation: Northwest Normal University,Northwest Normal University,,,, Fund Project: The National Natural Science Foundation of China (No. 41861040, No.41761047); The National Natural Science Foundation of Gansu Province (No.1506RJZA129) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以石羊河流域为研究区，基于干旱内陆河流域生态特征和遥感数据快速、客观、大面积观测的特点，采用遥感模型计算湿度、绿度、干度和热度等指标，并构建石羊河流域生态脆弱性评价指标体系，在此基础上运用空间主成分分析法（SPCA）对石羊河流域2000和2016年生态脆弱性时空演变及动因进行了分析。研究结果表明：（1）从各遥感指数空间分布来看，湿度和绿度指标均值在17年间呈增长趋势，证明该流域水源涵养能力变好，植被覆盖率变大；干度指标均值有所下降，表明该流域地表裸露程度有所降低；而与植被和水资源关系密切的地表温度均值呈逐年上升趋势，说明该流域水热平衡差异进一步增加，对未来生态脆弱性影响显著；（2）从全流域生态脆弱性时空演变特征来看，该流域主要以强度和中度脆弱为主，17年间生态脆弱性整体上呈缓慢降低趋势；（3）从不同的海拔生态脆弱性分布来看，中山区（1000-2000m）最高，高中山区（2000-3000m）次之，高山区（ > 3000m）最低，17年间中山区生态脆弱性有所下降，而高中山区与高山区却呈上升的趋势；（4）从不同的行政区划生态脆弱性来看，金川区、凉州区、永昌县、民勤县和古浪县整体上处于中度和强度脆弱水平，而天祝县和肃南县处于轻度和微度脆弱水平；（5）从生态脆弱性的演变动因来看，4个指标对石羊河流域生态脆弱性影响均为显著。2000年生态脆弱性的主导影响因子依次为热度 > 湿度 > 绿度 > 干度，而2016年为热度 > 干度 > 绿度 > 湿度。总的来看，石羊河流域生态脆弱程度近年来有所降低，但综合治理工作仍任重道远。本文的遥感方法和分析思路对该流域生态脆弱性保护及治理提供一定的理论基础和决策依据。 Abstract:With Shiyang River Basin as the study area, this paper used a remote sensing model to calculate indicators such as greenness, dryness, wetness and heat to construct ecological vulnerability assessment indicators based on the ecological characteristics of Arid Inland River Basin and the characteristics of rapid, objective, and large-area observational remote sensing, which was analyzed the spatio-temporal evolution and motivation of ecological vulnerability by Spatial Principal Component Analysis (SPCA) in 2000 and 2016 in Shiyang River Basin. The research showed that (1) From the spatial distribution of each remote sensing index, the mean of wetness and greenness showed an increasing trend in 17 years, which proved that the water conservation capacity was better and the vegetation coverage was larger in the basin. The mean of dryness had decreased, indicating that the degree of surface exposure of the basin had reduced. The mean of surface temperature closely related to vegetation and water resources was increasing year by year, which indicated that the differences of water and heat balance were further increasing in the basin, which had a significant effect on ecological vulnerability in the future. (2) From the spatio-temporal evolution of ecological vulnerability in the whole basin, the basin was mainly dominated by strong vulnerability and moderate vulnerability, and the ecological vulnerability had been slowly decreasing in 17 years. (3) From the ecological vulnerability distribution at different elevations, the highest in medium mountain area (1000-2000m), the medium in high-medium mountain area (2000-3000m), and the lowest in high mountain area (> 3000m). During 17 years of change, the ecological vulnerability of medium mountain area had decreased, while the high-medium mountain area and high mountain area were on the rise. (4) From the ecological vulnerability of different administrative divisions, Jinchuan, Liangzhou, Yongchang, Minqin and Gulang as a whole were at the level of moderate vulnerability and strong vulnerability, while Tianzhu and Sunan were at the level of slight vulnerability and light vulnerability. (5) From the motivation of ecological vulnerability, the four indicators had significant effects on the ecological vulnerability of Shiyang River Basin. The main influencing factors of ecological vulnerability were heat > wetness > greenness > dryness in 2000, and the main influencing factors of ecological vulnerability were heat > dryness > greenness > wetness in 2016. Overall, the ecological vulnerability of Shiyang River Basin had decreased in recent years, however the comprehensive management still has a long way to go. The remote sensing methods and analysis ideas of this paper provided theoretical basis and decision-making foundation for the ecological vulnerability protection and management in this basin. 参考文献 相似文献 引证文献

Contribution of recycled moisture to precipitation in the monsoon marginal zone: Estimate based on stable isotope data

The hydrogen and oxygen isotope composition of precipitation and water vapor are useful tracers in the water cycle. The water balance of inland river basins located in the monsoon marginal zone are difficult to determine, because little is known about the contribution of various vapor involved. Based on the three-component isotopic mixing model, the monthly precipitation, surface water and plant water isotope data of the seven sampling stations from April to October 2017 were used to assess the vapor contribution to precipitation in the Shiyang River basin.The average contribution of plant transpiration, land surface evaporation and advected vapor to precipitation accounted for 11%, 6% and 83% in the Mountain regions, for 21%, 7% and 72% in the Oasis regions, and for 10%, 5% and 85% in the Desert regions, respectively. The contribution of plant transpiration and surface evaporation vapor was similar in time variation, and the maximum value appeared in July. The average plant transpiration vapor contribution at each station was always greater than the surface evaporation vapor. Different landscape and special underlying surfaces are important factors influencing the difference in water vapor contribution. The average surface evaporation water vapor contribution of the Xiying (M1) station is the largest in the study area, with a contribution fraction of 9%. The contribution of Wuwei oasis recycled moisture can reach 30%, the plant transpiration vapor accounted for 73%.

Changes of glacier area in the Xiying River Basin, East Qilian Mountain, China

The Xiying River, one of eight tributaries of the Shiyang River, located at Lenglongling, east Qilian Mountain, is formed by the confluence of Luotuo, Qingyang, Ningchan, and Shuiguan rivers. In the Xiying River Basin, where have 42 glaciers which toward NE in the majority. In this study, three Landsat images and two topographic maps were used to extract boundaries by artificial vector quantization. Results show that glacier area in Xiying Basin increased slightly around 1987, since then, has been reduced considerably. From 1956/1972 to 2008, glacier area in Xiying River Basin was reduced by 20.76%, nine glaciers have disappeared, and below 4,100 m a.s.l., there is no ice cover. Variation tendency of glacier retreat was obviously controlled by orientation. Temperature increase especially after 1987 is the main reason of glacier shrinkage, where glaciers in the Xiying River Basin are more sensitive to climate change.

Hydrochemical assessment of the largest desert reservoir in arid oasis area in Asia

97735 artificial reservoirs have been built in China since 1950s, which could guarantee the supply of urban water and agricultural irrigation. In arid oasis area, only the water of reservoir is available as water resource. The study of hydrochemical characteristics is the prerequisite for evaluating the water quality of domestic water and irrigation water. In the Hongyashan Reservoir, the middle of the Shiyang River Basin and the Tengger desert and Badain Jaran desert, water samples were taken at different points of the lake for about 3 years. The chemical characteristics of the lake water and their influencing factors were studied. The results of the samples for the test have shown that water of the Hongyashan Reservoir is weakly alkaline. And the main compositions of ions in the water are Ca2+ and $$\text{HCO}_{3}^{ - }$$ , hydrochemical type is Ca–HCO3. In terms of the seasonal variation of Hongyashan Reservoir, except for $$\text{NO}_{3}^{ - }$$ , the ions in the rest of the water showed roughly the same changeable characteristics in that the composition of ion is higher in summer and autumn, but lower in winter and spring. This is consistent with the seasonal variation in runoff ions throughout the Shiyang River Basin. Ionic characteristics are consistent with the ionic values of dry lakes in the world, which are suitable for urban water and water for irrigation, but are slightly higher than the global lake background standard. Carbonate weathering products are the main source of water ions in Hongyashan Reservoir, and evaporation also affects the ion characteristics of water.

Land use/cover change and ITS eco-environment effect in Shiyang River Basin

Based on the origin data of Landsat TM images in 1980, 1995, 2000, 2006, 2012, this paper recurred to geoscience information spectrogram theory and utlized RS / GIS technologies, land use dynamic degree, land use transition matrixes and CA-Markov model to analyze the land use pattern change in Shiyang River Basin in the past 33 years, which was for the sake of discussing the spatial-temporal evolution rules and driving mechanism of land use in Shiyang River Basin. The results showed that: (1) There were apparent changes in the land use of Shiyang River Basin form 1980 to 2013. (2) in the past 33 years, the dynamic degrees of forest land, urban and rural resident construction land had relative large increase degree on the whole. (3) The main transition direction of land use types were arable land to grass land, grass land to unused land and unused land to arable land and forest land. (4) The CA-Markov model forecasting results indicated that there was no obvious change in land use construction in 2020. (5) The change of land use/cover brought desertification, mountainous runoff variation, the loss of water environment, vegetation coverage, water and soil, and a series of ecological environment problems.

Effects of deficit irrigation with saline water on soil water-salt distribution and water use efficiency of maize for seed production in arid Northwest China

In order to explore the utilization of groundwater resource, field experiments were conducted in 2012 and 2013 in the Shiyang River Basin of Northwest China. Altogether nine treatments included three water levels w1, w2 and w3 (1ETc, 2/3ETc, and 1/2ETc, ETc = 555 mm) in combination with three salinity levels s1, s2 and s3 (0.71 g/L, 3 g/L and 6 g/L).Soil water content, soil salt content and yield of maize for seed production were measured for studying the effects of deficit irrigation with saline water on water-salt distribution and water use efficiency of maize for seed production. The results showed that soil water content of saline water irrigation was higher than fresh water irrigation and soil salt content increased with increase of irrigation water salinity under the same irrigation water amount. Soil water content of deficit irrigation was lower than sufficient irrigation and soil salt content increased with decrease of irrigation water amount under the same irrigation water salinity. The soil salt accumulation increased gradually with increase of irrigation water salinity and decrease of irrigation water amount under the combined effect of irrigation water amount and irrigation water salinity. Irrigation with water salinity of 3 g/L and water amount of 370 mm will not cause a substantial yield reduction and could increase water use efficiency of maize for seed production. Irrigation schedule with irrigation water amount about 370 mm and irrigation water salinity below 3 g/L is recommended in this study area. The irrigation schedule of this study can be used in the practice of agricultural production and the results show a reasonably utilization of saline water, thereby supplying theoretical guidance for water-saving irrigation development.

Ecological degradation of an inland river basin and an evaluation of the spatial and distance effect on willingness to pay for its improvement

Improvements in the ecological attributes of inland rivers have been projected to provide considerable non-market benefits, and the monetary valuation of these attributes has steadily increased over the past several decades. The present study addresses the spatial heterogeneity of the public's preference for ecological attributes and the distance-decay effect of willingness to pay (WTP) to improve various attributes of the river basin. The results revealed that spatial heterogeneity exists among the individuals; for example, the respondents of Liangzhou County prefer a large improvement in the natural landscape, forest coverage, and eco-tourism and are willing to pay 491.89, 369.32, and 338.37yuan per year, respectively, for one unit improvement in these ecological attributes. Similarly, the respondents of Jinchang County value and are willing to pay 447.60, 431.81, and 318.18yuan for one unit improvement in tourism, forest coverage, and natural landscape, respectively. Furthermore, the results from the random parameter logit model show a significant distance-decay effect of the household WTP for ecological attributes. For example, the respondents living within 5km of the river are willing to pay more money, that is, 832.61, 365.62, and 353.05yuan per year for improving the natural landscape, water quantity, and grass cover, respectively. As the distance from the river increases, the corresponding WTP decreases, meaning that the respondents (users) living near the Shiyang River Basin are willing to pay more for ecological attribute improvement than those living far away from the river.

Optimization-Based Agricultural Water-Saving Potential Analysis in Minqin County, Gansu Province China

To deal with the contradictions that are caused by natural conditions and unreasonable water allocations in Minqin County, which are located downstream of the Shiyang River basin in arid northwest China, an optimization-based multi-scale calculation method was proposed for analyzing agricultural water-saving potential. Firstly, an optimization model was developed for allocating water and land resources legitimately with the conjunctive use of surface water and groundwater. Secondly, the groundwater equilibrium was fully considered in developing optimization model to achieve the ecological value of agricultural water savings. Then, multi-scale agricultural water-saving potentials were analyzed based on optimal results under different water-saving levels. These results provide local water managers with satisfactory economic benefit with higher water use efficiency. With reasonable management strategies of water and land resources, the ecosystem of Minqin County could gradually recover in the future. The results of the multi-scale water-saving potential analysis can help decision makers to identify desired water-saving plans that consider the coordinated development of the local economy, society, and ecology.

A dataset of human settlements along the Shiyang River basin in Qing and Republican China

A dataset of human settlements along the Shiyang River basin in Qing and Republican China

Formation and paleoenvironment of rhizoliths of Shiyang River Basin, Tengeri Desert, NW China

Rhizoliths found in bed of the late Quaternary paleolake Zhuyezhe, Minqin Basin, central Tengeri Desert, NW China were studied. Vegetation coverage is present at some locations in the paleolake area although, much of the bed area is covered with moving dunes. Rhizoliths are occasionally eroded out and exposed to the air. The morphology of the rhizoliths resembles singular or branching carbonated tubules which are hollow in their central part. The rhizoliths are black to grey, and are broken and scattered randomly on the sand surface of the lake bed. The lacustrine deposits are black greenish silt or silty clay with a large quantity of white petite lake snail shells. The possible plant types, sources and formation conditions of carbon dioxide and calcium, the sedimentary and diagenetic environments, and the process of rhizolith formation were discussed via examining rhizoliths macromorphology, studying the micromorphology and mineralogy by microscopy, cathodoluminescence and scanning electron microscope, and studying the chemical compositions of cementing minerals and fragments by energy dispersive X-ray spectra. The original roots of the rhizoliths belong to hydrophytes, such as Typha latifolia, Scirpus maritimus and Carex stenophylla. Lake snails and previous pollen data indicate that the rhizoliths formed in a sedimentary environment of shallow fresh water lake like marginal or palustrine areas during the Holocene. Shallow lake water disturbance by desert wind above the loose sandy sediment or soil was favoring the rhizoliths formation. A continuous supply of oxygen through water disturbance led to complete oxidation of roots and producing carbon dioxide. Dissolution of CO2 in water and so, carbonic acid production resulted in minerals weathering such as feldspar and primary carbonate particles and the release of K+ and Ca2+ ions. At presence of CO2 and Ca2+ saturated in the pore water around the roots of hydrophytes within the sediments or soil, carbonate precipitation occurred around the root channel and led to rhizoliths formation as tubules. The petrifaction process therefore, has happened in margin of the paleolake with shallow water and weak redox condition, which implies the suitability of rhizolith for reconstructing paleoenvironment.

Optimization of irrigation scheduling for spring wheat based on simulation-optimization model under uncertainty

Water scarcity is the major constraint to social-economic development in arid and semiarid regions, where irrigation needs to be scheduled properly for the main crops. In this study, a simulation-optimization model for crop optimal irrigation scheduling under uncertainty was developed to maximize the net benefit. The model integrated a water-driven crop model (AquaCrop) with the optimization model, and incorporated the generation technique for the interval values of hydrological parameters (i.e., precipitation and evapotranspiration) and crop market prices to deal with uncertainties in these variables. The water price was assumed constant. The model was calibrated based on field experimental data obtained in 2014 and validated using 2015 data. The field experiments involved spring wheat (Yongliang No. 4) at Shiyang River Basin Experiment Station in Wuwei City, Gansu Province of Northwest China. The model was then used to generate the optimal irrigation schedules under various irrigation amounts, irrigation events, initial soil water storage and crop market price under uncertainty. Results indicated that the model is applicable for reflecting the complexities of simulation-optimization under uncertainties for spring wheat irrigation water scheduling. The optimization results indicated that the optimal irrigation amount range was [185, 322] mm with the corresponding optimal net benefit of [1.05, 2.77] ×104 Yuan/hm2 and yield of [7.4, 7.6] kg/hm2 for extreme wet conditions in the basin (defined as the combination of the 5% frequency precipitation with 95% frequency evapotranspiration). For extreme dry conditions, the optimal irrigation amount range was [442, 507] mm with the optimal net benefit of [0.85, 2.64] ×104 Yuan/hm2 and the corresponding yield of [6.6, 7.4] kg/hm2. Results also showed that four irrigation events under higher initial soil water storage were more likely to produce the higher net benefit and the optimal net benefit would increase as the crop market price increases, as expected. This work can be used to guide irrigation management for local farmers.

The Influence of the Dam Construction on Plant Types in Shiyang River

Shiyang River Basin, as the high extent of exploitation & utilization of its resources and severe ecological & environmental issues, has always received much attention from scholars at home and abroad. The research, with reference to previous scholars’ conclusion and field survey, showed that the dam construction has resulted in the radical changes of water resource distribution as well as water resource utilization mode, which eventually had a strong effect on plant species and community change along the middle and lower reaches of the Shiyang River. The mainly result include: 1) The vegetation area, vegetation cover and biomass all decreased, plant types had changed from wet series to xeric series, Tamarix ramosissima, Kalidium foliatum and Phragmites australis etc community had gradually decreased, the vegetation with more drought tolerance had gradually occupy the dominant position, mainly includes Nitraria tangutorum, Reaumuria soongarica, Lycium ruthenicum etc, especially Nitraria tangutorum had become constructive species in most of the place in the middle and lower reaches of the Shiyang River since 1950's. 2) In the middle and lower reaches of the Shiyang River, The vegetation formed various adaptive way and xeromorphic characteristics in order to adapt the adverse environment such as the serious sand storm, the higher difference of temperature between day and night, the lower precipitation and the higher evaporation etc. The ring gate types gradually became the main types of structure of leaf in the region of relatively severe of human disturbance, the full gate types plants and normal types plants gradually increased in the region of relatively less of human disturbance, the type of structure of leaf changed from the ring gate types and normal types to irregular molding in the region of sharply decreased of groundwater. The dam construction caused reclaiming wasteland for farming on a large scale, disproportionate use of water resource, groundwater overdraft of and deterioration of water quality etc, and this eventually lead to change of areas and types of vegetation.

Effects of irrigation water salinity on soil salt content distribution, soil physical properties and water use efficiency of maize for seed production in arid Northwest China

In order to explore the use of groundwater resources, field experiments were conducted for three consecutive years during 2012-2014 in the Shiyang River basin of Northwest China. Irrigation was conducted using four different water salinity levels that were arranged in a split plot design. These four water salinity levels were s0, s3, s6 and s9 (0.71, 3, 6 and 9 g/L, respectively). The soil salt content, soil bulk density, soil porosity, saturated hydraulic conductivity, plant height, leaf area index and yield of maize for seed production were measured for studying the effects of saline water irrigation on soil salt content distribution, soil physical properties and water use efficiency. It was observed that higher salinity level of irrigation water and long duration of saline water irrigation resulted in more salt accumulation. Compared to initial values, the soil salt accumulation in 0-100 cm soil layer after three years of experiments for s0, s3, s6 and s9 was 0.189 mg/cm3, 0.654 mg/cm3, 0.717 mg/cm3 and 1.135 mg/cm3, respectively. Both greater salt levels in the irrigation water and frequent saline water irrigation led to greater soil bulk density, but poorer soil porosity and less saturated hydraulic conductivity. The saturated hydraulic conductivity decreased with increase in soil bulk density, but increased with improvement in soil porosity. It was noted that the maize height, leaf area index and maize yield gradually decreased with increase in water salinity. The maize yield decreased over 25% and the water use efficiency also gradually declined when irrigated with water containing 6 g/L and 9 g/L salinity levels. However, maize yield following saline water irrigation with 3 g/L decreased less than 20% and the decline in water use efficiency was not significant during the three-year experiment period. The results demonstrate that irrigation with saline water at the level of 6 g/L and 9 g/L in the study area is not suitable, while saline water irrigation with 3 g/L would be acceptable for a short duration together with salt leaching through spring irrigation before sowing. Keywords: saline water irrigation, soil salt content distribution, soil physical properties, maize for seed production, water use efficiency DOI: 10.25165/j.ijabe.20181103.3146 Citation: Yuan C F, Feng S Y, Wang J, Huo Z L, Ji Q Y. Effects of irrigation water salinity on soil salt content distribution, soil physical properties and water use efficiency of maize for seed production in arid Northwest China. Int J Agric & Biol Eng, 2018; 11(3): 137–145.

Resetting of the luminescence signal in modern riverbed cobbles along the course of the Shiyang River, China

Abstract Luminescence dating can potentially be applied to determine the burial ages of rock surfaces. As part of testing the reliability and applicability of this technique, we sampled a series of modern riverbed cobbles along the Shiyang River, which occupies an endorheic basin in northwest China. The infrared stimulated luminescence (IRSL) signal was measured as a function of depth for cobbles of two different lithologies (sandstone and granite). The results show that (i) the bleaching rate of the signal for light-coloured granite is higher than for opaque dark-coloured sandstone, because granite is bleached to greater depths than sandstone; (ii) cobble daylight bleaching depths show a downstream increasing trend, with almost all bleaching occurring in the upstream section; and (iii) despite possible abrasion of the upper surface of granite cobbles, the bleaching depth in the upper surface is greater than in the lower surface, indicating longer exposure times for the upper faces of cobbles. This work has important implications for the age-dating of fluvial deposits and the potential application of luminescence techniques to understand transport and deposition in fluvial environments.