Damage by wind-blown sand and its control measures along the Taklimakan Desert Highway in China

Desertification is one of the most serious environmental problems in the world,especially in the arid desert regions.Combating desertification,therefore,is an urgent task on a regional or even global scale.The Taklimakan Desert in China is the second largest mobile desert in the world and has been called the'Dead Sea'due to few organisms can exist in such a harsh environment.The Taklimakan Desert Highway,the longest desert highway(a total length of 446 km)across the mobile desert in the world,was built in the 1990s within the Taklimakan Desert.It has an important strategic significance regarding oil and gas resources exploration and plays a vital role in the socio-economic development of southern Xinjiang,China.However,wind-blow sand seriously damages the smoothness of the desert highway and,in this case,mechanical sand control system(including sand barrier fences and straw checkerboards)was used early in the life of the desert highway to protect the road.Unfortunately,more than 70%of the sand barrier fences and straw checkerboards have lost their functions,and the desert highway has often been buried and frequently blocked since 1999.To solve this problem,a long artificial shelterbelt with the length of 437 km was built along the desert highway since 2000.However,some potential problems still exist for the sustainable development of the desert highway,such as water shortage,strong sandstorms,extreme environmental characteristics and large maintenance costs.The study aims to provide an overview of the damages caused by wind-blown sand and the effects of sand control measures along the Taklimakan Desert Highway.Ultimately,we provide some suggestions for the biological sand control system to ensure the sustainable development of the Taklimakan Desert Highway,such as screening drought-resistant species to reduce the irrigation requirement and ensure the sound development of groundwater,screening halophytes to restore vegetation in the case of soil salinization,and planting cash crops,such as Cistanche,Wolfberry,Apocynum and other cash crops to decrease the high cost of maintenance on highways and shelterbelts.     

Monthly and seasonal streamflow forecasting of large dryland catchments in Brazil

Streamflow forecasting in drylands is challenging.Data are scarce,catchments are highly humanmodified and streamflow exhibits strong nonlinear responses to rainfall.The goal of this study was to evaluate the monthly and seasonal streamflow forecasting in two large catchments in the Jaguaribe River Basin in the Brazilian semi-arid area.We adopted four different lead times:one month ahead for monthly scale and two,three and four months ahead for seasonal scale.The gaps of the historic streamflow series were filled up by using rainfall-runoff modelling.Then,time series model techniques were applied,i.e.,the locally constant,the locally averaged,the k-nearest-neighbours algorithm(k-NN)and the autoregressive(AR)model.The criterion of reliability of the validation results is that the forecast is more skillful than streamflow climatology.Our approach outperformed the streamflow climatology for all monthly streamflows.On average,the former was 25%better than the latter.The seasonal streamflow forecasting(SSF)was also reliable(on average,20%better than the climatology),failing slightly only for the high flow season of one catchment(6%worse than the climatology).Considering an uncertainty envelope(probabilistic forecasting),which was considerably narrower than the data standard deviation,the streamflow forecasting performance increased by about 50%at both scales.The forecast errors were mainly driven by the streamflow intra-seasonality at monthly scale,while they were by the forecast lead time at seasonal scale.The best-fit and worst-fit time series model were the k-NN approach and the AR model,respectively.The rainfall-runoff modelling outputs played an important role in improving streamflow forecasting for one streamgauge that showed 35%of data gaps.The developed data-driven approach is mathematical and computationally very simple,demands few resources to accomplish its operational implementation and is applicable to other dryland watersheds.Our findings may be part of drought forecasting systems and potentially help allocating water months in advance.Moreover,the developed strategy can serve as a baseline for more complex streamflow forecast systems.     

蔬菜枯萎病和青枯病的识别与治理

多种蔬菜都会发生枯萎病和青枯病.如西瓜、甜瓜、黄瓜、冬瓜、蚕豆、豇豆、辣椒、番茄、马铃薯等会发生枯萎病;辣椒、番茄、马铃薯、茄子和一些豆科蔬菜既会发生枯萎病,也发生青枯病.这两种病害在蔬菜上很常见,而且,发生又严重,常给蔬菜造成3～5成的损失,甚至绝收.因此,正确地区分和识别这两种病害,并有针对性地采取相应措施进行防治尤为重要.     

Variation of soil physical-chemical characteristics in salt-affected soil in the Qarhan Salt Lake,Qaidam Basin

Soil salinization has adverse effects on the soil physical-chemical characteristics.However,little is known about the changes in soil salt ion concentrations and other soil physical-chemical characteristics within the Qarhan Salt Lake and at different soil depths in the surrounding areas.Here,we selected five sampling sites(S1,S2,S3,S4,and S5)alongside the Qarhan Salt Lake and in the Xidatan segment of the Kunlun Mountains to investigate the relationship among soil salt ion concentrations,soil physical-chemical characteristics,and environmental variables in April 2019.The results indicated that most sites had strongly saline and very strongly saline conditions.The main salt ions present in the soil were Na⁺,K⁺,and Cl^-.Soil nutrients and soil microbial biomass(SMB)were significantly affected by the salinity(P<0.05).Moreover,soil salt ions(Na⁺,K⁺,Ca2+,Mg²⁺,Cl^-,CO₃^2-,SO₄^2-,and HCO₃^-)were positively correlated with electrical conductivity(EC)and soil water content(SWC),but negatively related to altitude and soil depth.Unlike soil salt ions,soil nutrients and SMB were positively correlated with altitude,but negatively related to EC and SWC.Moreover,soil nutrients and SMB were negatively correlated with soil salt ions.In conclusion,soil nutrients and SMB were mainly influenced by salinity,and were related to altitude,soil depth,and SWC in the areas from the Qarhan Salt Lake to the Xidatan segment.These results imply that the soil quality(mainly evaluated by soil physical-chemical characteristics)is mainly influenced by soil salt ions in the areas surrounding the Qarhan Salt Lake.Our results provide an accurate prediction of how the soil salt ions,soil nutrients,and SMB respond to the changes along a salt gradient.The underlying mechanisms controlling the soil salt ion distribution,soil nutrients,and SMB in an extremely arid desert climate playa should be studied in greater detail in the future.     

Land cover change and eco-environmental quality response of different geomorphic units on the Chinese Loess Plateau

Land cover in the Chinese Loess Plateau has undergone dramatic changes since the late 1980s.Revealing the trend in land cover change and eco-environmental quality response of different geomorphic units in this stage is a realistic requirement for promoting sustainable development of the Chinese Loess Plateau.Based on the data of geomorphic units and land cover in 1990,2000,2010 and 2018 of the Chinese Loess Plateau,we studied the trend of land cover change and eco-environmental quality response of different geomorphic units by using a significance index of land cover change,a proportion index of land cover change and an eco-environmental response model.The results indicated that from 1990 to 2018,the areas of forestland and construction land substantially increased,whereas those of cropland,grassland,wetland and unused land considerably decreased.Land cover change exhibited large geomorphic differences,and the main conversion of land cover was from cropland into other land types.Unstable trend of land cover change in the loess tablelands and sandy loess hills declined,whereas the unstable trends in the other geomorphic units enhanced.Eco-environmental quality varied among different geomorphic units.The expansion of construction land and degradation of forestland,grassland and wetland resulted in the deterioration of eco-environmental quality.The conversion of cropland and unused land into forestland and grassland,and the conversion of grassland into forestland were the main factors that drove the improvement of eco-environmental quality.The findings of this study may provide theoretical reference and support decision making for the optimization of land use structure and the improvement of eco-environmental quality on the Chinese Loess Plateau.     

Tectonic geomorphological characteristics for evolution of the Manas Lake

Owing to global climatic changes and human activities,the lakes have changed dramatically in the Junggar Basin of Xinjiang in recent 50 years. Based on the remote sensing images from Beijing Satellite No.1 in 2006 together with the measured topographical data in 1999 and other data since the 1950s,this paper analyzes mainly the features of landforms around the Manas Lake and the changes of feeding sources of the lake. The results are as follows:(1) Tectonic movement brought about the fundamental geomorphological basis for lacustrine evolution,and the Manas Lake is one of small lakes broken up from the Old Manas Lake due to tectonic movement and drought climate; the Manas Lake had existed before the Manas River flowed into it in 1915. The geomorphologic evidences for evolution of the Manas Lake include:(a) Diluvial fans and old channels at the north of the lake indicate that the rivers originating from the north mountains of the Junggar Basin had fed the Old Manas Lake and now still feed the lake as seasonal rivers; (b) The Old Manas Lake was fed by many rivers originating from the mountains,except for the Manas River,from the evidence of small lakes around the Manas Lake,old channels,alluvial fans,etc.; (c) The elevations of the alluvial and diluvial fans are near to the 280 m a.s.l. and all of the small lakes and lacustrine plains are within the range of the 280 m a.s.l.,which may prove that the elevation of the Old Manas Lake was about 280 m a.s.l.; (d) Core analysis of the Manas Lake area also indicates that the Manas Lake has existed since Late Pleistocene epoch. (2) Analysis on the feeding relations between the lakes and the lacustrine evolution shows that human activities are one of main driving forces of the lacustrine evolution in recent 50 years,and it is the precondition of restoring and maintaining the lacutrine wetlands in the study area to satisfy the feeding of the Baiyang and Manas rivers to the Manas Lake.     

农田大面积使用"毒饵站"投药技术灭鼠的操作和体会

近年由于鼠类天敌减少.气候变暖等诸多因素,龙江县鼠情发生日趋严重,直接影响粮食安全生产和人民正常生活.灭鼠工作迫在眉睫.农民对统一灭鼠要求强烈.针对本县实际情况,2007年春季对4个水稻主产乡,开展了春季农田统一灭鼠2万hm2,全部采用"毒饵站"技术,效果显著.     

浅谈南阳林业货场检疫工作方法

南阳市地处河南省西南部、南接湖北、西连陕西,是豫、鄂、陕三省交汇地带。南阳市货场是焦枝与宁西铁路的交通枢纽。每天都有大量的森林植物及其产品在这里交易和流通,是重要的物质集散地。同时也带来了危险性病虫传播蔓延的极大的隐患,因此,搞好货场检疫,保护林业发展,显得十分紧迫和重要。     

BAS 765 UA H防除玉米田杂草的效果

BAS 765 UA H对玉米田杂草辣子草、铁苋菜、凹头苋、自生油菜、碎米莎草等防效优良,低剂量对马唐防效稍差.BAS 765 UA H的速效性较好,一般药后7 d可显效.对玉米安全.从防效和经济效益综合考虑,田间施用量为1 000～1 500 ml/hm2,若田间马唐较多,施用量应提高到1 500～2 000 ml/hm2.     

环丙醇类制剂对雄性布氏田鼠的不育作用

紫外(UV)辐射作用于"病菌一植物"病害系统影响植物病害的发生发展,主要包括两个方面一是UV辐射对植物病原菌孢子的萌发、芽管伸长、菌丝生长等光生物学效应,不同种属的菌种对UV辐射存在不同的响应机制;二是寄主植物从形态、生理生化等方面对UV作出响应,导致植物的抗病性发生变化.研究证实,中、短波UV辐射可抑制病菌孢子萌发,减少病害的发病率;长波UV辐射对病菌孢子的萌发有诱导作用,可提高病害发病率.根据UV辐射水平、病菌侵染程度及植物抗性品种等因素的影响,UV辐射对不同植物病害系统也存在不同的作用机制.该文作者就近年来国内外有关辐射对植物病害影响的研究进展进行综述.     

几种茉莉害虫的为害与防治

茉莉在我国约有一千七百年的栽培历史。茉莉花是制作花茶的主要原料,我国茉莉花茶的生产、销售量要占花茶总量的80%以上,产区辽阔,产量最大,销路最广。茉莉害虫是影响茉莉花生产的主要因素之一。为此,自20世纪70年代开始,我们就对江西主要茶区大面积栽培(以露地为主,其次是盆栽)的茉莉害虫的为害与防治作了一些调查研究,现将初步结果报道如下。     

对我国《集装箱熏蒸规程》的修改建议

本文结合一线熏蒸工作的实际,对我国现行SN／T1124－2002《集装箱熏蒸规程》进行了剖析,着重就集装箱气密性检测、箱内熏蒸气体浓度快速均匀分布和熏蒸气体浓度检测方面的技术方法问题进行了研究,提出了建设性的改进意见,以更好地保证熏蒸处理的有效性。     

农药分装登记

PD20081773-F00-0140山东省绿士农药有限公司(山东省齐河经济开发区金能大道北首251100 0534-5756113)硫磺·多菌灵/50%/可湿性粉剂/多菌灵、硫磺/2009.03.11至2010.03.11/低毒PD20083974-F00-0146山东省绿士农药有限公司(山东省齐河经济开发区金能大道北首251100 0534-5756113)噁霜·锰锌//可湿性粉剂/噁霜灵、代森锰锌/2009.03.11至2010.03.11/低毒     

两种化合物联合诱导黄瓜对炭疽病的抗病性研究初报

通过用草酸钾和硫酸亚铁2种化合物的8种组合方式,诱导黄瓜对炭疽病的抗病性,证明用两种化合物分别独立诱导和联合诱导均有一定的诱导效应,但联合诱导比独立诱导所获得的诱导效应明显增强.其中,首次用草酸钾诱导,间隔3 d后再用硫酸亚铁进行第2次诱导,所获得的诱导效应最高.田间试验达较好的防治效果.     

中国土壤学会第十一届全国会员代表大会暨第七届海峡两岸土壤肥料学术交流研讨会2008年9月24～27日在北京召开

土壤资源是人类的生存平台和粮食生产基地,其重要性不言而喻.我国人均耕地、林地、牧草地数量均远远低于世界人均数量,并且整体质量偏低、退化沙化现象较为严重,加之近年城市化的扩张,非农占用耕地大量增加,土壤资源与社会发展之间的矛盾日益突出.     

疏花蒺藜在阜新的分布、危害及防控措施

疏花蒺藜草(Cenchrus pakaciflorus Benth.)俗名草蒺藜、草狗子,为禾本科1年生草本植物。原产于北美洲及热带沿海地区的沙质土壤上,现在辽西的锦州、朝阳及阜新均有分布。疏花蒺藜草适应能力强,繁殖迅速,极易传播,在严重侵染地区人畜难行,     

广东口岸首次截获葡萄腊实蝇

2007年1月和3月广州机场出入境检验检疫局分别截获来自尼日利亚旅客携带的金叶树（Chrysophyllum sp）果实,经实验室检查发现有实蝇幼虫为害,进一步室内培养羽化出成虫,经广东检验检疫技术中心植检室有关专家鉴定为一种重要的检疫性害虫葡萄腊实蝇（Ceratitis （Pardalas-pis） ditissimma （Miuuro））,为全国口岸首次截获。     

不同缓冲液对烟草环斑病毒胶体金免疫层析试纸条测试的影响

烟草环斑病毒(Tobacco ringspot virus,TRSV)为豇豆花叶病毒科(Comoviridae)线虫传病毒属(Nepovirus)的典型成员.TRSV寄主范围广泛,可为害54科246种草本和木本植物,在许多重要农作物如大豆、烟草上为害严重.