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1.
在7m/s、15m/s和20m/s的实验风速下,对不同浓度土壤凝结剂处理的沙障模型进行风洞吹蚀实验。实验结果表明:抗风蚀强度以40%浓度处理最强,20%最弱,但30%浓度防风蚀效果较为实用。在乌兰布和沙漠东北缘绿洲边缘的流动沙丘,采用较为适用的30%浓度的土壤凝结剂进行1m×1m,1.5m×1.5m,2m×2m等3种不同规格沙障喷洒实验,通过对风速、粗糙度、风沙流结构特征值,以及沙障的蚀积状况进行调查,其结果表明,各种规格的沙障中,1m×1m的沙障性能最好,1.5m×15m次之,2m×2m最差。沙丘不同部位沙障的抗蚀力不同,迎风坡受损程度和风蚀率最高。 相似文献
2.
为了探究可降解沙障铺设5 a后土壤粒度及有机质含量特征,采集库布齐沙漠东南缘铺设5 a后不同规格(0.5 m×0.5 m,1 m×1 m和2 m×2 m)、不同坡位(坡底、坡中、坡顶)的PLA沙障内近地表层(0—3 cm)土壤样品,通过激光粒度仪测试并分析了土壤粒度、有机质含量的变化情况及二者的相关性。结果表明:(1)PLA沙障内主要以细砂和粗砂为主,随着铺设规格的增加细砂含量逐渐增加,2 m×2 m(80.66%)>1 m×1 m(75.8%)>0.5 m×0.5 m(45.15%),每种规格坡顶处细砂含量最高分别为23.39%,31.73%,41.17%,坡中粗砂含量最高分别为44.91%,36.42%,42.88%。(2)障格内分选性均变差,峰态偏离正态分布,沉积物颗粒频率分布曲线部分波段变窄,表层颗粒逐渐细粒化。(3)土壤有机质含量表现出1 m×1 m>0.5 m×0.5 m>CK>2 m×2 m的规律; 3种规格有机质含量均表现为坡底>坡中>坡顶; 且极细砂与有机质含量呈现显著正相关,与中砂呈现显著负相关。上述结果说明,对于本研究区内,铺设5 a后1m×1m规格PLA沙障防护效益更优,且1 m×1 m规格和坡底处有利于有机质的积累,极细砂和中砂是有机质积累的关键粒级。 相似文献
3.
沙柳沙障防风效益模拟试验研究 总被引：2，自引：0，他引：2
研究设定了2组试验,用沙柳柳条人工插成方格沙障,一组方格沙障高度1 m,规格分别为4 m×4 m,5 m×5m,6 m×6 m;另外一组方格沙障高度1.5 m,规格分别为6 m×6 m,7.5 m×7.5m,9 m×9 m。测定了每种规格沙障的地表粗糙度,防风效益。试验结果表明:在宽高比相同的情况下,1 m高的沙柳沙障的粗糙度大于1.5 m高的沙障,防风效益也好于1.5 m高的沙障;而在沙障高度一定的情况下,随着沙障面积的增大,沙障的防风效益在逐渐减弱。 相似文献
4.
[目的]分析不同铺设规格生物基可降解聚乳酸(PLA)沙障障格内风蚀稳定凹曲面形态特征、断面轮廓及蚀积效应等指标,为聚乳酸沙袋沙障规格优选提供理论依据。[方法]以内蒙古自治区吉兰泰盐湖周边流动沙垄铺设的0.5 m×0.5 m,1 m×1 m,1.5 m×1.5 m和2 m×2 m规格的聚乳酸沙袋沙障为研究对象,待风季后测量障格内稳定凹曲面蚀积形态,绘制凹曲面形态图并计算蚀积参数等。[结果] 4种规格沙障障格内均能形成稳定的凹曲面,且呈四周高中间低的整体格局。0.5 m×0.5 m,1 m×1 m,1.5 m×1.5 m和2 m×2 m障格内的净堆积强度分别为17.29,7.09,0.61,-8.2 g/cm~2。[结论]障格内稳定的凹曲面形成前,0.5 m×0.5 m和1 m×1 m障格内以堆积为主;1.5 m×1.5 m障格内风蚀堆积近乎平衡;2 m×2 m障格内部在布设初期呈风蚀状态,但稳定凹曲面形成后,仍可控制地表风蚀。 相似文献
5.
[目的] 明确机械沙障铺设对风沙区地表可蚀性特征的影响,为防沙工程中沙障的合理应用提供理论依据。[方法] 采取库布齐沙漠北缘迎风坡不同年限铺设的生物基可降解聚乳酸（PLA）沙袋沙障、沙柳沙障和芦苇沙障不同坡位的土壤样品,分析了地表0—20 cm深度土壤有机质含量、土壤粒径组成和土壤可蚀性K值。[结果] ①沙障铺设后利于土壤有机质含量增加,其中2 m×2 m沙柳沙障对土壤有机质的积累效果最好,且迎风坡上部土壤有机质含量相对较少。②沙障铺设使得障格内黏粒、粉粒和细砂含量增加,随设障年限的增加其呈增加趋势;土壤0—20 cm范围内均以细砂为主。③铺设机械沙障可降低土壤可蚀性,各立地条件下沙丘下部障格内土壤抗蚀性最好;3种机械沙障中沙柳沙障抗蚀性较高;随设障年限增加障格内土壤抗蚀性增强,设障4 a后,2 m×2 m铺设规格障格内的土壤受侵蚀风险较小;土壤可蚀性K值与土壤有机质含量呈极显著（p<0.01）负相关。[结论] 沙障铺设使土壤有机质含量增加,利于细粒物质的积累,增强土壤抗蚀性,是治理流动沙丘有效的风蚀防治措施。建议在库布齐沙漠北缘铺设机械沙障时,可采用迎风坡上部铺设1 m×1 m的生物基可降解聚乳酸（PLA）沙袋沙障,中部铺设2 m×2 m的沙柳沙障,下部铺设2 m×2 m的生物基可降解聚乳酸（PLA）沙袋沙障的模式。 相似文献
6.
为了探究PLA沙障对乌珠穆沁沙地沙化治理的效果,以方格状铺设不同规格(方格边长0.5 m×0.5 m, 1 m×1 m, 2 m×2 m和3 m×3 m)PLA沙障,以不同规格沙障影响的风蚀特征为研究对象,裸沙地设置对照(CK),采用美国HOBO便携式风速采集仪观测距地表10,20,50,100,200 cm高度的风速,同时使用自动旋转集沙仪收集近地表0—30 cm高度输沙量,分析了防风效能、固沙效益和风沙流挟沙粒径的变化特征。结果表明：(1) PLA沙障规格小于3 m×3 m时,风速廓线呈“S”型变化趋势;PLA沙障平均的地表粗糙度为0.64 cm, CK的平均粗糙度为0.51 cm,粗糙度提高了25.48%。(2)铺设PLA沙障后输沙量降低了38.72%～75.69%;PLA沙障输沙率随高度呈现良好的指数关系(R2>0.77);1 m×1 m和2 m×2 m沙障的固沙效益高于其他2种规格沙障,3 m×3 m规格的固沙效益最低,基本接近CK。(3)乌珠穆沁沙地风蚀物颗粒大小介于2～500μm,且大部分颗粒为100～250μm的细沙;铺设PLA沙障后,障格内... 相似文献
7.
为了解新材料聚酯纤维(PLA)沙障对沙丘土壤硬度的影响,通过测定铺设PLA沙障沙丘表层的土壤硬度,并以铺设麦草沙障沙丘及裸沙丘为对照,对比研究各种规格、迎风坡、坡顶及背风坡土壤硬度的差异。结果表明:铺设PLA沙障沙丘表层土壤硬度显著高于麦草沙障沙丘(P<0.001),且2者土壤硬度均显著高于未铺设沙障的裸沙丘(P<0.001);2 m×2 m和1 m×1 m PLA沙障土壤硬度比较接近,均显著小于3 m×3m规格的(P<0.01),而麦草沙障3种规格的土壤硬度差异较小;2种沙障所在沙丘不同部位土壤硬度变化趋势相似,均是迎风坡的最大,坡顶次之,背风坡的最小;PLA沙障及麦草沙障单个障格内的土壤硬度分布都是不均匀的,并且二者的土壤硬度分布规律存在差异。 相似文献
8.
纤维材料沙袋沙障是一种新兴的固沙材料,具有施工运输方便,可重复利用等优点。通过在古兰泰铺设纤维沙袋沙障,分析了1m×1m不同孔隙度(15%,25%,35%)三种规格对风速廓线、输沙量、粗糙度等的影响。得出了低立式纤维材料沙袋沙障具有明显的防风固沙效应,三种规格沙障对风沙流结构的影响不同,35%规格对风的削弱作用最强;三种规格都具有明显的控制风蚀基准面作用,其中15%规格的对风蚀基准面的控制最稳定;由于沙袋的特殊性,其障内地表曲面不同于一般格状沙障的稳定凹曲面,与风向有一定的相关性。 相似文献
9.
沙袋沙障凹曲面特性研究 总被引：4，自引：3，他引：1
按不同规格,不同坡位,对设置一年后、总面积近25 000 m2的沙袋沙障内凹曲面特性进行了调查研究.结果表明,沙障规格和设置部位对沙障凹曲面的特征均有显著影响.通过3种规格的对比,1 m×1m规格沙袋沙障更利于稳定凹曲面的形成;3个坡位相比,坡顶处形成的凹曲面较为稳定.不同规格及不同坡位沙障凹曲面的N-S和W-E两个走向垂直剖面轮廓曲线都基本符合一元二次函数,且N-S剖面较W-E剖面陡,表明凹曲面特性受风力及风向影响较大.沙袋沙障稳定凹曲面的障间蚀积系数在1/10左右.障内植物对凹曲面形态特征影响较大,植物具有明显的灌丛堆效应,可进一步增强沙丘的稳定性.大规格的沙障若一定时间内无植被生长,会导致沙障很快失去防护作用. 相似文献
10.
聚乳酸纤维沙障对表层土壤含水量的影响 总被引：1，自引：0，他引：1
在乌兰布和沙漠西南缘选择大小、走向相近的裸沙丘分别铺设聚乳酸纤维( PLA)沙障与麦草沙障,设计规格为1m×1m、2m×2m、3m×3m.从2008年开始连续3年对2种沙障不同规格、不同坡位表层土壤含水量进行测定,同时以未铺设任何沙障的裸沙丘作为对照,比较新型材料PLA沙障与传统沙障麦草沙障对表层土壤含水量的长时间影响.结果表明:1)PLA沙障与麦草沙障以及裸沙丘含水量都随年份的增加而增加,2类沙障含水量增长幅度明显优于裸沙丘;2)就沙障规格而言,长时间保持土壤水分,效果最好的是PLA沙障2m×2m规格:3)在0～10 cm深度,PLA沙障土壤含水量表现为迎风坡＞背风坡＞坡顶,麦草沙障与PLA沙障相反;4)在10～20 cm深度,PLA沙障土壤含水量表现为坡顶＞迎风坡＞背风坡,麦草沙障同样与PLA沙障相反. 相似文献
11.
低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响 总被引：2，自引：2，他引：0
【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。 相似文献
12.
Aleš Lebeda Ivana Doležalová Eva Křístková Barbora Mieslerová 《Genetic Resources and Crop Evolution》2001,48(2):153-164
Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions. 相似文献
13.
Kyle Devey Michael Mucalo Gordon Rajendram Joseph Lane 《Communications in Soil Science and Plant Analysis》2015,46(4):72-80
Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing. 相似文献
14.
Thomas Larsen Jesper Luxhøi Jakob Magid Lars Stoumann Jensen Paul Henning Krogh 《Biology and Fertility of Soils》2007,44(1):59-68
We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization
and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition
with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the
decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots
with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass,
soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration,
N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially
(<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation
in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils,
indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but
the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation
for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community
performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea. 相似文献
15.
《中国生态农业学报》2014,(6)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
16.
《中国生态农业学报》2014,(7)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
17.
《中国生态农业学报》2014,(8)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
18.
I.L. Boyd 《Biological conservation》2010,143(7):1664-1674
“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options. 相似文献
19.
Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage 总被引：1，自引：0，他引：1
Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate. 相似文献
20.
M.A. Callaham Jr. J.M. BlairT.C. Todd D.J. KitchenM.R. Whiles 《Soil biology & biochemistry》2003,35(8):1079-1093
The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils. 相似文献