Stoichiometric features of C,N, and P in soil and litter of Tamarix cones and their relationship with environmental factors in the Taklimakan Desert,China

Journal of Soils and Sediments - The main objectives of this study were to explore the soil and litter carbon (C), nitrogen (N), and phosphorus (P) stoichiometric features in the Tamarix cones...     

罗布泊钾盐矿区绿化施工与管护技术

罗布泊钾盐矿区绿化工程项目区位于素有"绿化禁区"之称的罗布泊腹地,该工程克服了极端干旱、高温、多风大风、盐土和盐尘等诸多不利环境因素,采用了适宜的盐土改良措施和管护技术,让"死亡之海"出现了人工绿色,同时改善了矿区的办公环境,为极端环境下的绿化工程提供了成功案例。     

“一喷三防”施药时间对小麦病虫害的防治效果

为准确掌握"一喷三防"施药时间对小麦主要病虫害的防治效果,选择小麦抽穗前(4月22日)、小麦抽穗约20%(4月27日)、小麦抽穗约70%(4月30日)和小麦扬花末期(5月9日)4个时期,以w=4.5%高效氯氰菊酯乳油300mL/hm2、w=15%三唑酮可湿性粉剂1 200g/hm2、KH2PO41 500g/hm2 3种溶液的混合液为供试药剂,以穗期不施药为对照进行田间试验,研究"一喷三防"不同施药时间对当地4种小麦穗期主要病虫害(小麦条锈病、小麦赤霉病、小麦蚜虫和小麦吸浆虫)的防治效果。结果表明,不同施药时间,小麦主要病虫害的防治效果和保产效果不同。在以蚜虫为小麦穗期主要害虫,且喷药1次的情况下,从保产效果来看,"一喷三防"的最佳喷药时间为小麦抽穗约70%时,其次为小麦抽穗约20%时。喷药时间过早或过晚,保产效果均明显下降。     

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.     

人工防护林作用下风沙土成土过程的研究进展

人工防护林是防风固沙,有效防治沙漠化的重要措施之一。在沙漠地区建立人工防护林,可以有效防止土壤侵蚀,促进土壤有机质及粘粒积累,促使地表结皮形成,不仅对流沙起到了固定作用,而且促进了风沙土的成土过程。本文结合植物－土壤相互作用理论,分别从植物地上部分对养分的阻滞和聚集,以及减少土壤表面蒸发;地下部分的固沙和物质的分解与营养补给等方面综述了生物防护林在风沙土成土过程中的作用。同时,从以往的研究发现,在风沙土成土过程中,土壤机械组成变细,比重和容重减小;土壤剖面结构分异显著,分层增加;土壤含水量和养分显著聚集;土壤微生物数量和种类增加,活性增强,酶活性也大幅度提高。总之,随着沙漠生物防护林的建造,林下风沙土性质发生了明显的改良作用,逐渐发展成固定风沙土。这说明人工防护林和风沙土的成土过程是协同发展的,这不仅有利于沙漠防护林的可持续管护,也有利于沙漠化的防治和退化生态系统的恢复与重建。     

低温胁迫对甜瓜嫁接苗抗逆生理指标的研究

本试验以"圣砧一号"、"世纪星"、"新土佐"、"黑籽南瓜"为砧木,分别与薄皮甜瓜"玉美人"进行嫁接,采用靠接法,组成四个砧穗复合体,分别以自根"玉美人"甜瓜、"圣砧一号"、"世纪星"、"新土佐"、"黑籽南瓜"砧木作对照,共9个处理,在嫁接苗成活后,生长发育正常时,利用人工气候箱,对9个处理分别进行2 h、4h、6 h、8 h、12 h(小时)不同时间的低温处理.低温处理温度为3℃,以15℃为对照.结果表明:各处理之间,以嫁接"圣砧一号"和嫁接的"世纪星"处理在低温下脯氨酸积累较多,嫁接苗次之,自根甜瓜苗酶活性最低.表明嫁接能提高甜瓜幼苗的抗冷性,表现为低温胁迫后嫁接苗的脯氨酸(Pro)含量高,在各个处理中,以嫁接"圣砧一号"和嫁接的"世纪星"处理脯氨酸积累较多,说明耐冷性强于其他处理.适合生产中大面积推广.     

咸水灌溉对沙漠防护林植物根系分布及风沙土演变的影响

以塔克拉玛干沙漠公路沿线防护林植物及土壤为研究对象,综合研究咸水灌溉对植物根系及风沙土演变的作用。结果表明,柽柳的根系较深,达到200 cm,而梭梭和沙拐枣根系为100~150 cm。林地表层土壤出现显著的土壤盐分(8 m S cm-1)和养分聚集现象。但在植物根系分布最多的40~60 cm的土壤层中并没有出现土壤盐渍化现象(1.0 m S cm-1)。防护林地土壤养分含量显著高于流沙地,且土壤的黏粒和粉粒以及土壤团聚体和团聚体稳定性均显著增加。综上所述,地下咸水灌溉并未对植物的正常生长产生盐害或毒害,同时有利于沙漠风沙土的演变。     

Growth and sustainability of Suaeda salsa in the Lop Nur,China

Extremely saline soils are very harsh environments for the growth and survival of most plant species, however, halophytes can grow well. The underlying mechanism of halophyte to resist high saline is not well understood by us. This study was conducted at the potash mine near the Lop Nur, China, where the effects of the halophyte Suaeda salsa L. on the saline-alkaline soils and its growth and sustainability were investigated. Four plots(in which the salt encrustation layers were removed), with different soil treatments were evaluated:(1) undisturbed soil, with no additional treatment(T1);(2) the slag soil zone, in which a 40-cm layer of slag was placed on the undisturbed soil surface(T2);(3) slag+sandy soil, in which a 20-cm layer of slag was placed in the lower layer and 20 cm of sandy soil, taken from an area about 70 km away from Lop Nur potash mine, where Tamarix species were growing, was placed in the upper layer(T3); and(4) a 40-cm sandy soil layer taken from the area where Tamarix species were growing was placed on undisturbed soil(T4). Soil nutrient contents increased in the four treatments, but salt content only decreased in the T1 treatment. Salt content in the T4 treatment increased over the two-year period, which may be partly attributed to salt deposition from wind-blown dust within the mine and salt accumulation within the surface soil(0–20 cm) in response to high evaporative demands. The S. salsa plants exhibited greater improvements in growth under the T4 treatment than under the T1, T2, and T3 treatments, which demonstrated that low levels of salinity are beneficial for the growth of this species. The T1 treatment was sustainable because of its low cost and superior soil improvement characteristics. Therefore, S. salsa plants not only reduced soil salinity and increased soil nutrient levels, but also ameliorated the plant growth environment, which would be beneficial for both the ecological restoration of the Lop Nur area and similar areas throughout the world.     

塔克拉玛干沙漠腹地人工植被及土壤CNP的化学计量特征

生态化学计量学是研究生态过程和生态作用中化学元素平衡的科学。极端环境中进行植物叶片与土壤中营养元素含量及变化研究,对于揭示植物对营养元素的需要和当地土壤的养分供给能力,以及植物对环境的适应与反馈能力具有十分重要的意义。以塔克拉玛干沙漠腹地塔中植物园生长良好的25种人工植被及其生境为研究对象,运用方差分析、相关分析综合研究植物叶片及土壤的化学计量特征及其相互关系。结果显示:塔克拉玛干沙漠腹地25种人工植被叶片C、N、P的平均含量分别为(386.7±46.6)、(24.7±8.1)和(1.8±0.78) mg/g;叶片C:N、C:P及 N:P分别为(17.5±6.7)、(249.2±102.8)、(15.0±5.6)。其中豆科植物N含量极显著高于非豆科植物(P<0.001)。不同生活型植物的C、N、P含量均存在显著差异,C、N、P含量在3种生活型的大小顺序为草本>灌木>乔木。C:N和N:P在不同生活型植物间不存在显著差异(P>0.05),而乔木和灌木的C:P显著高于草本植物(P< 0.05)。相关分析表明植物的叶片C:N、C:P都与相应的N、P含量呈现极显著负相关性(P<0.001),而叶片N含量与P含量的变化并不相关(P> 0.05)。土壤C、N、P养分元素含量远低于全国的平均水平,尤其是N含量(<0.2 mg/g);土壤C与N存在着极显著的正相关关系(P<0.01),而C与P、N与P间的相关性并不显著(P>0.05)。以上研究结果表明,受极端环境的限制,塔克拉玛干沙漠人工植被植物对养分元素的利用效率显著低于全国陆地植物的平均水平,不同科和不同生活型功能群植物对环境的适应能力显著不同,表现出显著的养分适应策略差异性。     

塔克拉玛干沙漠腹地参考作物蒸散量与蒸发皿蒸发量的对比分析

利用2005-2010年塔克拉玛干沙漠腹地气象资料计算了极端干旱区塔克拉玛干沙漠腹地参考作物蒸散量(ET0),并与气象站蒸发皿蒸发量(Ep)进行了对比分析及影响因素的灰色关联度排序。结果表明:极端干旱区ET0最大值出现于7月,最小值则出现在1月;Ep最大值分别出现在6月,最小值出现在12月。灰色关联分析表明,在年时间尺度上与ET0关系最为紧密的气象因子是Umean,其次是Tmax,而影响Ep气象因子最为紧密的气象因子是Tmax,其次是Umean;在春、夏、秋、冬四个季节尺度上夏季对影响ET0和Ep的气象因子差异最大。ET0与Ep在春、秋、冬三个季节都成极显著关系,而在夏季呈显著线性关系,因此在不同时间尺度上二者可以进行互相替换。