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15篇 您的检索式:作者名="Atsushi TSUNEKAWA"
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1重新认知青藏高原围栏禁牧的作用显示文摘围栏禁牧是中国政府为恢复青藏高原等地退化草地而采取的一项重要政策.然而,关于围栏对高寒草地生态系统功能和服务及其对牧民生计的影响,人们的认识还很有限.本研究荟萃分析和基于问卷的调查显示,围栏禁牧时间长达4年和8年的时间里可以有效地促进高寒草甸以及草原的地上植被生长,更长时间的围栏并没有带来任何生态和经济效益.研究还发现,围栏限制了野生动物的活动范围,增加了非围栏地区的放牧压力,降低了牧民的满意度,且给地区和国家政府带来了巨大的财政成本.因此,建议在适当的情况下,应鼓励传统的游牧方式来利用草地,在严重退化的草地上应采用短期围栏(4~8年),在重要的野生动物栖息地应避免使用围栏,特别是受保护的大型哺乳动物分布的区域.研究结果可为青藏高原草地可持续管理提供一定的参考.孙建 刘苗 傅伯杰 David Kemp 赵文武 刘国华 韩国栋 Andreas Wilkes 鲁旭阳 陈有超 程根伟 周天财 侯阁 詹天宇 彭飞 Hua Shang 徐明 石培礼 何永涛 李猛 王金牛 Atsushi Tsunekawa 周华坤 刘宇 李裕瑞 刘世梁 2020Science Bulletin2020,65,16:24
2Index-based assessment of agricultural drought in a semi-arid region of Inner Mongolia, China显示文摘Agricultural drought is a type of natural disaster that seriously impacts food security.Because the relationships among short-term rainfall,soil moisture,and crop growth are complex,accurate identification of a drought situation is difficult.In this study,using a conceptual model based on the relationship between water deficit and crop yield reduction,we evaluated the drought process in a typical rainfed agricultural region,Hailar county in Inner Mongolia autonomous region,China.To quantify drought,we used the precipitation-based Standardized Precipitation Index(SPI),the soil moisture-based Crop Moisture Index(CMI),as well as the Normalized Difference Vegetation Index(NDVI).Correlation analysis was conducted to examine the relationships between dekad-scale drought indices during the growing season(May–September)and final yield,according to data collection from 2000 to 2010.The results show that crop yield has positive relationships with CMI from mid-June to mid-July and with the NDVI anomaly throughout July,but no correlation with SPI.Further analysis of the relationship between the two drought indices shows that the NDVI anomaly responds to CMI with a lag of 1 dekad,particularly in July.To examine the feasibility of employing these indices for monitoring the drought process at a dekad time scale,a detailed drought assessment was carried out for selected drought years.The results confirm that the soil moisture-based vegetation indices in the late vegetative to early reproductive growth stages can be used to detect agricultural drought in the study area.Therefore,the framework of the conceptual model developed for drought monitoring can be employed to support drought mitigation in the rainfed agricultural region of Northern China.Rui LI Atsushi TSUNEKAWA Mitsuru TSUBO 2014Journal of Arid Land2014,6,1:8
3Dynamics and hotspots of soil erosion and management scenarios of the Central Rift Valley of Ethiopia显示文摘大多数在埃塞俄比亚的中央裂缝山谷的低地干旱或半干旱并且在降级,与干旱的经常的出现。土壤侵蚀走水路在雨季期间是在这个区域的一个严重问题,导致为水身体的衰退农业生产,减少的食物安全,和沉积风险。然而,没有这个问题或可能的管理答案的系统的学习。满足这需要,我们分析了侵蚀从 1973 ~ 2006 评估的土壤,识别侵蚀热点,和建议可能的土壤保存情形。我们用通用土壤损失方程和地理信息系统软件估计了土壤损失 dynamicity,就在下列三个时期的陆地使用变化而言:1973, 1985 和 2006。我们以识别热点的侵蚀严厉,地形学,和陆地使用描绘了分水岭并且求婚,当模特儿,并且评估了各种各样的分水岭管理情形减轻这个问题。分别地,土壤侵蚀由于植被降级并且特别地从 1973 ~ 2006 显著地增加了,与在 1973, 1985,和 2006 的 31, 38,和 56 t ha1 的年度率几千公顷进农田的森林或树林的变换。观察土壤侵蚀率远离这个国家的土壤损失的可容忍的率并且因此要求迫切土壤保存干预,特别在热点区域。我们建议为减少的八种情形玷污损失并且评估了他们的有效性。恢复降级的土地(使用的 exclosures 和种的植被) 和在农田的安装石头侵蚀控制结构(石头东亚各国之堤岸) 分别地在 12.6% 和 63.8% 减少了全部的土壤损失。由综合管理(侵蚀控制结构和 exclosures ) 与超过 20 t ha1 的年度土壤损失对待热点区域是最有效的途径,减少在 87.8% 的土壤损失。Derege Tsegaye MESHESHA Atsushi TSUNEKAWA Mitsuru TSUBO Nigussie HAREGEWEYN 2012International Journal of Sediment Research2012,27,1:6
4Derivation of salt content in salinized soil from hyperspectral reflectance data: A case study at Minqin Oasis, Northwest China显示文摘Soil salinization is a serious ecological and environmental problem because it adversely affects sustainable development worldwide, especially in arid and semi-arid regions. It is crucial and urgent that advanced technologies are used to efficiently and accurately assess the status of salinization processes. Case studies to determine the relations between particular types of salinization and their spectral reflectances are essential because of the distinctive characteristics of the reflectance spectra of particular salts. During April 2015 we collected surface soil samples(0–10 cm depth) at 64 field sites in the downstream area of Minqin Oasis in Northwest China, an area that is undergoing serious salinization. We developed a linear model for determination of salt content in soil from hyperspectral data as follows. First, we undertook chemical analysis of the soil samples to determine their soluble salt contents. We then measured the reflectance spectra of the soil samples, which we post-processed using a continuum-removed reflectance algorithm to enhance the absorption features and better discriminate subtle differences in spectral features. We applied a normalized difference salinity index to the continuum-removed hyperspectral data to obtain all possible waveband pairs. Correlation of the indices obtained for all of the waveband pairs with the wavebands corresponding to measured soil salinities showed that two wavebands centred at wavelengths of 1358 and 2382 nm had the highest sensitivity to salinity. We then applied the linear regression modelling to the data from half of the soil samples to develop a soil salinity index for the relationships between wavebands and laboratory measured soluble salt content. We used the hyperspectral data from the remaining samples to validate the model. The salt content in soil from Minqin Oasis were well produced by the model. Our results indicate that wavelengths at 1358 and 2382 nm are the optimal wavebands for monitoring the concentrations of chlorine and sulphate compounds, the predominant salts at Minqin Oasis. Our modelling provides a reference for future case studies on the use of hyperspectral data for predictive quantitative estimation of salt content in soils in arid regions. Further research is warranted on the application of this method to remotely sensed hyperspectral data to investigate its potential use for large-scale mapping of the extent and severity of soil salinity.QIAN Tana Atsushi TSUNEKAWA PENG Fei Tsugiyuki MASUNAGA WANG Tao LI Rui 2019Journal of Arid Land2019,11,1:3
5Increase in medium-size rainfall events will enhance the C-sequestration capacity of biological soil crusts显示文摘Biological soil crusts(BSCs) play important roles in the carbon(C) balance in arid regions. Net C balance of BSCs is strongly dependent on rainfall and consequent activation of microbes in the BSCs. The compensation-rainfall size for BSCs(the minimum rainfall amount for a positive net C balance) is assumed to be different with BSCs of different developmental stages. A field experiment with simulated rainfall amount(SRA) of 0, 1, 5, 10, 20, and 40 mm was conducted to examine the C fluxes and compensation-rainfall size of BSCs in different parts of fixed dunes in the ecotone between the Badain Jaran Desert and the Minqin Oasis. We found algae-lichen crust on the interdunes and crest, algae crust on the leeward side, and lichen-moss crust on the windward. Even a small rainfall(1 mm) can activate both photosynthesis and respiration of all types of BSCs. The gross ecosystem production, ecosystem respiration, and net ecosystem exchange were significantly affected by SRA, hours after the simulated rainfall, position on a dune, and their interactions. The rapid activation of photosynthesis provides a C source and therefore could be responsible for the increase of C efflux after each rewetting. C-uptake and-emission capacity of all the BSCs positively correlated with rainfall size, with the lowest C fluxes on the leeward side. The compensation rainfall for a net C uptake was 3.80, 15.54, 8.62, and 1.88 mm for BSCs on the interdunes, the leeward side, the crest, and the windward side, respectively. The whole dune started to show a net C uptake with an SRA of 5 mm and maximized with an SRA of about 30 mm. The compensation-rainfall size is negatively correlated with chlorophyll content. Our results suggest that BSCs will be favored in terms of C balance, and sand dune stabilization could be sustained with an increasing frequency of 5-10 mm rainfall events in the desert-oasis transitional zone.-CuiHua Huang Fei Peng Itaru Shibata Jun Luo Xian Xue Kinya Akashi Atsushi Tsunekawa Tao Wang 2019Research in Cold and Arid Regions2019,11,1:2
6Effect of Polyacrylamide integrated with other soil amendments on runoff and soil loss:Case study from northwest Ethiopia显示文摘Anionic polyacrylamide(PAM)has the potential to reduce soil erosion through soil conditioning.However,a comprehensive study about its effectiveness especially when applied combined with other amendments have rarely been conducted in the tropical highland climatic conditions,such as in Ethiopia.The study assessed the effectiveness of PAM(P=40 kg ha^(-1))alone or integrated with other soil amendments such as gypsum(G=5 t ha^(-1)),lime(L=4 t ha^(-1))and biochar(B=8 t ha^(-1))on runoff and soil loss at Aba Gerima watershed in the Upper Blue Nile basin,northwest of Ethiopia,where there is high erosion-caused soil degradation.A total of 79 daily runoff and sediment data were collected from eight runoff plots(1.3m×4m)with three replications planted with teff(Eragrostis tef)crop for two years(2018&2019)rainy seasons.Associated changes in soil physicochemical properties and crop growth parameters were investigated.Treatments reduced seasonal runoff by 12–39%and soil loss by 13–53%.The highest reduction in runoff was observed from P+B and PAM treatments while the highest reduction in soil loss was observed from that of P+L and PAM treatments.Integrating PAM with other amendments improved soil structural stability,moisture content,soil pH(P+L)and organic matter(P+B),leading to favorable environment for crop growth(biomass yield)and reduced runoff and soil erosion.Unlike PAM,biochar and lime amendments may need more time after application to be more effective.Hence continuing the field experiment and studying physico-chemical mechanisms for extended period will better elucidate their single or combined effectiveness over time.Birhanu Kebede Atsushi Tsunekawa Nigussie Haregeweyn Mitsuru Tsubo Temesgen Mulualem Amrakh I.Mamedov Derege Tsegaye Meshesha Enyew Adgo Ayele Almaw Fenta Kindiye Ebabu Tsugiyuki Masunaga 2022International Soil and Water Conservation Research2022,10,3:1
7Urine output and resultant osmotic water shift are major determinants of plasma sodium level in syndrome of inappropriate antidiuretic hormone secretion显示文摘Ataru Okumura Kota Ishikawa Risako Watanabe Taku Tsunekawa Chikako Asai Atsushi Kiyota Minemori Watanabe Yutaka Oiso 2013Translational Research2013,,1:1
8Efficiency of soil and water conservation practices in different agro-ecological environments in the Upper Blue Nile Basin of Ethiopia显示文摘In developing countries such as Ethiopia, research to develop and promote soil and water conservation practices rarely addressed regional diversity. Using a water-balance approach in this study, we used runoff plots from three sites, each representing a different agro-ecological environment, e.g., high, mid and low in both elevation and rainfall, in the Upper Blue Nile Basin of Ethiopia to examine the runoff response and runoff conservation efficiency of a range of different soil and water conservation measures and their impacts on soil moisture. The plots at each site represented common land use types(cultivated vs. non-agricultural land use types) and slopes(gentle and steep). Seasonal runoff from control plots in the highlands ranged 214–560 versus 253–475 mm at midlands and 119–200 mm at lowlands. The three soil and water conservation techniques applied in cultivated land increased runoff conservation efficiency by 32% to 51%, depending on the site. At the moist subtropical site in a highland region, soil and water conservation increased soil moisture enough to potentially cause waterlogging, which was absent at the lowrainfall sites. Soil bunds combined with Vetiveria zizanioides grass in cultivated land and short trenches in grassland conserved the most runoff(51% and 55%, respectively). Runoff responses showed high spatial variation within and between land use types, causing high variation in soil and water conservation efficiency. Our results highlight the need to understand the role of the agro-ecological environment in the success of soil and water conservation measures to control runoff and hydrological dynamics. This understanding will support policy development to promote the adoption of suitable techniques that can be tested at other locations with similar soil, climatic, and topographic conditions.Dagnenet SULTAN Atsushi TSUNEKAWA Nigussie HAREGEWEYN Enyew ADGO Mitsuru TSUBO Derege T MESHESHA Tsugiyuki MASUNAGA Dagnachew AKLOG Ayele A FENTA Kindiye EBABU 2018Journal of Arid Land2018,10,2:1
9The dynamics of urban expansion and its impacts on land use/land cover change and small-scale farmers living near the urban fringe:A case study of Bahir Dar,Ethiopia显示文摘Nigussie Haregeweyn Genetu Fikadu Atsushi Tsunekawa 2012Landscape and Urban Planning2012,,106:1
10Changes in ecosystem service values strongly influenced by human activities in contrasting agro-ecological environments显示文摘Background:Evaluating the impacts of land-use/land-cover(LULC)changes on ecosystem service values(ESVs)is essential for sustainable use and management of ecosystems.In this study,we evaluated the impact of human activity driven LULC changes on ESVs over the period 1982–2016/17 in contrasting agro-ecological environments:Guder(highland),Aba Gerima(midland),and Debatie(lowland)watersheds of the Upper Blue Nile basin,Ethiopia.Results:During the study period,the continuous expansion of cultivated land at the expense of natural vegetation(bushland,forest,and grazing land)severely reduced the total ESV by about US$58 thousand(35%)in Aba Gerima and US$31 thousand(29%)in Debatie watersheds.In contrast,the unprecedented expansion of plantations,mainly through the planting of Acacia decurrens,led,from 2006,to a ESV rebound by about US$71 thousand(54%)in Guder watershed,after it had decreased by about US$61 thousand(32%)between 1982 and 2006.The reduction in natural forest area was the major contributor to the loss of total ESV in the study watersheds,ranging from US$31 thousand(63%)in Debatie to US$96.9 thousand(70%)in Guder between 1982 and 2016/17.On an areaspecific basis,LULC changes reduced the average ESV from US$560 ha^(−1) year^(−1)(1982)in Guder to US$306 ha^(−1) year^(−1)(2017)in Debatie watersheds.Specific ESVs such as provisioning(mainly as food production)and regulating services(mainly as erosion control and climate regulation)accounted for most of the total ESVs estimated for the study watersheds.Conclusions:In most cases,the total and specific ESVs of the watersheds were negatively associated with the population growth,which in turn was positively associated with the expansion of cultivated land over the study period.In Guder,however,ESVs were positively associated with population growth,especially after 2012.This is mainly due to the expansion of Acacia decurrens plantations.Our results suggest,therefore,that future policy measures and directions should focus on improving vegetation cover through planting multipurpose trees such as Acacia decurrens to prevent future loss of ESV in the midland and lowland regions of the Upper Blue Nile basin and beyond.However,caution must be taken during plantation of invasive species as they may have undesirable consequences.Mulatu Liyew Berihun Atsushi Tsunekawa Nigussie Haregeweyn Mitsuru Tsubo Ayele Almaw Fenta 2021Ecological Processes2021,10,1:1
11Considerations on Sustainable Agriculture and Rural Development in Dryland Areas显示文摘Drylands of the world cover 41% of the Earth's land surface and are a direct source of livelihood for 6.5 billion people, especially in developing countries. However, nearly all drylands are at risk of land degradation as a result of human activities. Poverty and desertification in dryland areas are major problems threatening sustainable agriculture and rural development in dryland areas.Several topics that are significant for sustainable agriculture and rural development for food security and environmental rehabilitation in dryland areas were stressed in this paper.LI Li TSUNEKAWA Atsushi TSUBO Mitsuru KOIKE Atsushi 2010Journal of Northeast Agricultural University(English Edition)2010,17,4:0
12Tillage and crop management impacts on soil loss and crop yields in northwestern Ethiopia显示文摘Lack of appropriate agronomic practices is one of the major causes for soil erosion and low yields in teff(Eragrostis tef[Zucc.])production in Ethiopia.A 3-yr study was conducted at the Aba Gerima watershed in northwestern Ethiopia,to investigate the effects of two tillage practices(reduced tillage[RT]and conventional tillage[CT]),two planting methods(row planting[RP]and broadcast planting[BP]),and two compaction options(with[+T]and without[-T]trampling)on soil loss and teff yields in a split-split plot arrangement.Sediment concentration ranged from 0.01 to 5.37 g L^(-1)(mean,0.25 g L^(-1))in our study.Accordingly,the estimated total(August-October)soil loss ranged from 0.2 to 0.5 t ha^(-1)(mean,0.3 t ha^(-1)).The sediment concentration and total soil loss were significantly influenced(P<0.05)by tillage,planting methods,and trampling only in the third monitoring year.RT reduced soil loss by 19% relative to that of CT,whereas RP resulted in a 13%reduction in soil loss over BP.The-T plots showed a 15%reduction in soil loss as compared to+T plots.Results revealed significant increase in soil total carbon and nitrogen in RT and-T.Less soil loss and greater teff grain yield were obtained in plots with improved agronomic practices(RT and RP)compared to conventional ones(CT and BP).Based on our findings we conclude that the use of RT,RP,and-T practices can effectively minimize soil loss without any crop yield penalty.Fekremariam Asargew Mihretie Atsushi Tsunekawa Nigussie Haregeweyn Enyew Adgo Mitsuru Tsubo Kindiye Ebabu Tsugiyuki Masunaga Birhanu Kebede Derege Tsegaye Meshesha Wataru Tsuji Muluken Bayable Mulatu Liyew Berihun 2022International Soil and Water Conservation Research2022,10,1:0
13Toward a sustainable grassland ecosystem worldwide显示文摘Globally,grasslands,covering about 40%of the Earth’s land area,are vital for supporting important ecosystem functions,services,and livelihoods of millions of humans.Currently,grassland degradation is a major threat to the maintenance of ecological services,1 food security,and sustainable development,and directly hinders the global efforts with meeting goals and targets such as the The UN Decade on Ecosystem Restoration and Sustainable Development Goals(SDGs).Remote sensing approaches have the advantages of spanning large geographical areas withmultiple spatial,spectral,and temporal resolutions.In global scale,remote sensing methods used normalized difference vegetation index to determine net primary productivity(NPP),which still is the effectivemethod to indicate grassland conditions.To master the general situation of grassland,we analyzed the global spatial-temporal variation of NPP from 2001 to 2019 at the pixel level across the globe.As presented in Figure 1A,the NPP values of global grasslands showed an obvious variation trend,which indicated a considerable distribution pattern of spatial heterogeneity.The decreasing and increasing trend in grassland NPP covered approximately 25.3%and 74.5%of the total grassland area,respectively.Jian Sun Yi Wang Shilong Piao Miao Liu Guodong Han Junran Li Eryuan Liang Tien Ming Lee Guohua Liu Andreas Wilkes Shiliang Liu Wenwu Zhao Huakun Zhou Mesenbet Yibeltal Mulatu Liyew Berihun Dawn Browning Ayele Almaw Fenta Atsushi Tsunekawa Joel Brown Walter Willms Mitsuru Tsubo 2022The Innovation2022,3,4:0
14Effect of stones on the sand saltation threshold during natural sand and dust storms in a stony desert in Tsogt-Ovoo in the Gobi Desert,Mongolia显示文摘Non-erodible elements such as stones and vegetation are key to controlling wind erosion and dust emission in drylands.Stony deserts are widely distributed in the Gobi Desert,but the effect of stones on wind erosion and dust emission have not been well studied,except under artificial conditions.In this study,we evaluated the effect of stones on wind erosion and dust emission by measuring the sand saltation threshold in a stony desert in Tsogt-Ovoo in the Gobi Desert,Mongolia,under natural surface conditions during sand and dust storms.We quantified the amount of stones by measuring the roughness density,and determined the threshold friction velocity for sand saltation by measuring wind speed and sand saltation count.Our results showed that the threshold friction velocity increased with the roughness density of stones.In the northern part of the study area,where neither a surface crust nor vegetation was observed,the roughness density of stones was 0.000 in a topographic depression(TD),0.050 on a northern slope(N.SL),and 0.160 on the northern mountain(N.MT).The mean threshold friction velocity values were 0.23,0.41,and 0.57 m/s at the TD,N.SL,and N.MT sites,respectively.In the southern part of the study area,the roughness density values of stones were 0.000 and 0.070-0.320 at the TD and southern slope sites,respectively,and the mean threshold friction velocities were 0.23 and 0.45-0.71 m/s,respectively.We further compared the observed threshold friction velocities with simulated threshold friction velocities using Raupach's theoretical roughness correction and the measured roughness density values,and found that Raupach's roughness correction worked very well in the simulation of threshold friction velocity in the stony desert.This means that the results of our stone measurement can be applied to a numerical dust model.Batjargal BUYANTOGTOKH Yasunori KUROSAKI Atsushi TSUNEKAWA Mitsuru TSUBO Batdelger GANTSETSEG Amarsaikhan DAVAADORJ Masahide ISHIZUKA Tsuyoshi T SEKIYAMA Taichu Y TANAKA Takashi MAKI 2021Journal of Arid Land2021,13,7:0
15Global analysis of cover management and support practice factors that control soil erosion and conservation显示文摘Cover management and support practices largely control the magnitude and variability of soil erosion.Although soil erosion models account for their importance(particularly by C-and P-factors in the Revised Universal Soil Loss Equation),obtaining spatially explicit quantitative field data on these factors remains challenging.Hence,also our insight into the effects of soil conservation measures at larger spatial scales remains limited.We analyzed the variation in C-and P-factors caused by human activities and climatic variables by reviewing 255 published articles reporting measured or calculated C-and P-factor values.We found a wide variation in both factor values across climatic zones,land use or cover types,and support practices.The average C-factor values decreased from arid(0.26)to humid(0.15)climates,whereas the average P-factor values increased(from 0.33 to 0.47,respectively).Thus,support practices reduce soil loss more effectively in drylands and drought-prone areas.The global average C-factor varies by one order of magnitude from cropland(0.34)to forest(0.03).Among the major crops,the average C-factor was highest for maize(0.42)followed by potato(0.40),among the major orchard crops,it was highest for olive(0.31),followed by vineyards(0.26).The P-factor ranged from 0.62 for contouring in cropland plots to 0.19 for trenches in uncultivated land.The C-factor results indicate that cultivated lands requiring intensive site preparation and weeding are most vulnerable to soil loss by sheet and rill erosion.The low P-factor for trenches,reduced tillage cultivation,and terraces suggests that significantly decreased soil loss is possible by implementing more efficient management practices.These results improve our understanding of the variation in C-and P-factors and support large-scale integrated catchment management interventions by applying soil erosion models where it is difficult to empirically determine the impact of particular land use or cover types and support practices:the datasets compiled in this study can support further modeling and land management attempts in different countries and geographic regions.Kindiye Ebabu Atsushi Tsunekawa Nigussie Haregeweyn Mitsuru Tsubo Enyew Adgo Ayele Almaw Fenta Derege Tsegaye Meshesha Mulatu Liyew Berihun Dagnenet Sultan Matthias Vanmaercke Panos Panagos Pasquale Borrelli Eddy J.Langendoen Jean Poesen 2022International Soil and Water Conservation Research2022,10,2:0
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