河西走廊沙漠化严重,绿洲生态环境脆弱.节水等关键技术的突破与成熟发展为荒漠绿洲生态防护林体系建设及其生态产业发展提供了机遇与挑战.通过立足本地生态和资源优势,增强生态意识,发掘优质资源,加强"卡脖子"技术攻关,改善生态环境,发展特色优势产业,助力乡村振兴,以生态振兴促进农业农村系统性发展.

为了探清干旱荒漠区生物土壤结皮对易漂移性植物种子定居影响及作用机制，以巴丹吉林沙漠南缘结皮前期以及藻类、地衣、藓类阶段结皮为场所，通过人工补充种子与野外长期监测的方法对红砂种子在生物结皮上流失动态、种子宿存微区特征以及种子宿存量与微区面积间的关系等进行研究。结果表明：（1）生物土壤结皮发育过程中，地表枯落物、微坑、龟裂缝、长藓的面积百分比均发生了显著变化，即：枯落物呈现出增大（藻类阶段）—稳定不变（地衣阶段）—减小（藓类阶段）的趋势，微坑、龟裂缝均先增大后减小（峰值在地衣阶段）,长藓持续增大。（2）4个阶段的种子流失速度或定居率两两之间存在显著差异，流失速度大小依次为：结皮前期＞藻类阶段＞藓类阶段＞地衣阶段，定居率大小为：地衣阶段＞藓类阶段＞藻类阶段＞结皮前期。（3）生物土壤结皮上定居的种子仅宿存于枯落物、微坑、龟裂缝、长藓上，这4种微区上定居种子数与其面积之间均存在显著正相关关系，其关系均可用二次项y=ax~2+bx+c（a≠0）表示，等面积微区内的定居种子数大小依次为：龟裂缝＞枯落物＞微坑＞长藓。因此认为，生物土壤结皮对红砂种子定居的影响主要是单位面积上枯落物、龟裂缝、微坑、长藓等微区面积改变引起的。

缺水和水资源不合理利用,造成了我国北方荒漠化扩张,绿洲萎缩.节水技术在农业集约化生产中应用较多,但林业中应用少.筛选因地制宜的节水造林技术,提高造林成活率,是节水林业发展的有效途径.荷兰Groasis保水节水造林技术是由抗老化聚丙烯容器制成的集储水、自然水收集与毛细纤维渗灌供水系统组成的保水节水技术,引进后在造林时一次性储水20 L左右,并利用 自然降水,为苗木持续供水半年至一年,可显著提高苗木成活率和生长量.

In this study, Apocynum venetum and Poacynum hendersonii were used to study the effects of salt stress on seed germination and seedling growth at different concentrations (0, 0.3%, 0.6%, 0.9%, 1.2%, 1.5%, 1.8% and 2.1%) of NaCl. The results showed that with increasing NaCl concentration, germination rate (GR), germination potential (GP), and germination index (GI) of A. venetum and P. hendersonii seeds showed a remarkably decreasing trend, with delayed mean germination time, and inhibited length of germ and radicle. The degree of inhibition on each index was more obvious at higher concentrations (1.5%～2.1%). From the two species, there was no significant difference in germination rate and germination potential at low concentration (P > 0.05), and the effect of high concentration on A. venetum was significantly higher than that of P. hendersonii (P < 0.05). When NaCl concentration was 0.9%, the length of germ P. hendersonii was significantly longer than that of A. venetum, and the other differences were not significant (P > 0.05). At 0.3%, 0.6%, 0.9% and 2.1% the length of radicle P. hendersonii was significantly longer than that of A. venetum, and there was no significant difference in other concentrations (P < 0.05). The relative salt injury rate was higher in A. venetum seed than P. hendersonii, but the difference was not significant (P > 0.05). Thus, the salt tolerance was higher in P. hendersonii than A. venetum. The optimum salt concentration range of A. venetum was 0～1.5%, while the optimum salt concentration range of P. hendersonii was 0～1.8%.

通过不同渗透势溶液PEG-6000(聚乙二醇)模拟干旱胁迫环境和不同钠盐(NaCl、Na2SO4、NaHCO3、复合钠盐)溶液胁迫环境,对沙蒿种子萌发抗旱性和耐盐性特征进行研究[1].结果表明:干旱胁迫和钠盐胁迫均能显著影响沙蒿种子的萌发;随着PEG和不同钠盐溶液浓度的增加,抗旱指数、发芽指数、发芽率和发芽势等指标均呈显著降低趋势.其中,沙蒿种子萌发PEG溶液浓度的适宜值为5％、临界值为30％、极限值为35％;复合盐溶液在盐碱交互胁迫下,整体降低趋势更为显著.当使用NaCl溶液处理沙蒿种子,溶液浓度在0.2％～0.6％时,平均发芽时间呈不同幅度的缩短趋势,溶液浓度大于0.6％以后,平均发芽时间随着浓度增加有不同幅度的延长趋势[3],说明NaCl溶液胁迫降低了沙蒿种子的活力和发芽的整齐度.相同钠盐溶液浓度处理,对沙蒿种子中萌发盐害作用大致趋势为NaHCO3>NaCl>Na2SO4>复合盐.

黑果枸杞是我国西北干旱地区特有的兼具耐盐碱和抗旱特性的野生灌木,可正常生长于大多植物无法生长的高盐渍化环境中,并发挥其生态效益;此外,黑果枸杞同时具备药用、食用功效,已被应用于饮料、保健品、药品等诸多行业,具有广阔的市场前景.丰富的营养价值、良好的经济价值及潜在的药用价值,使黑果枸杞野生资源受到大规模掠夺性开采,天然分布区环境日益恶劣,植被严重退化甚至死亡,其他伴生植物的生长也受到很大的威胁,野生居群的规模及分布区域呈迅速减小的趋势,其资源远远不能满足市场的需求.对荒漠区黑果枸杞现阶段研究成果进行了综合分析.

Wind-sand flow is determined by the properties of underlying surface,but one of the factors of influencing wind-sand flow is vegetation condition.Multistep sand collecting instrument 100 cm high was installed in different ages of abandoned lands.The characteristics of vegetations in different growth stages and wind-sand flow were measured.The affection vegetation of different growth stages and sand transport rate of wind-sand flow were analyzed.The results showed 1) the vegetation coverage,quantity,species richness and annual sand transport rate exhibited a regular change with the ages of abandoned lands,species quantity,species richness exhibited a significant positive correlation with abandoned age.2) The sand transport rate gradually reduced with the increase of the height,the wind-sand flow was mainly concentrated in the surface within 0-20 cm,the nearer to the top,the smaller varied range was.3) Under the condition of vegetation different growth stages in the same wind speed,the sediment transport rate in vegetation growth peak period was significantly less than the beginning of the growth,at the same time,which was significantly associated with vegetation coverage and the number of herbaceous plants.4) The sand transport rate showed decreasing trend with vegetation increased at different heights,the sand transport rate percentage gradually decreased with the increase of height.5) The shrub species was rare in arid desert area farmland.The impact of herbage on community mainly concentrated in the rainy season,then influenced the sand transport rate of the farmland.The study results would provide scientific basis for plant management measures of the farmland.

不同年代退耕地受土壤水分与植被的影响,地表风沙流输沙量呈规律性变化.以石羊河流域下游民勤治沙站不同年代退耕地为研究对象,用风沙流观测仪测定了不同年代退耕地上0～100 cm的风沙流输沙量,分析了不同年代退耕地风沙流年输沙量等特征.研究结果表明:(1)输沙量总体上表现为随退耕时间的增加而呈增加趋势,退耕时间越长,年输沙量越大,同时输沙量也受周边地貌的影响;(2)不同年代退耕地输沙量随季节呈规律性变化,而且与风速关系密切,输沙量大小与当地风季发生规律相一致;(3)退耕地风沙流输沙量与退耕年代总体上呈二元线性相关关系,相关系数为0.88;(4)通过聚类分析将10个不同年代退耕地风沙流输沙量分为三类,17年为一类,13年为一类,其余退耕年代的为一类.不同年代退耕地因退耕时间的不同,受周边地貌,植被的影响,其风沙流输沙量有很大差异,研究结果为退耕地利用与治理提供了科学依据.

15 Aeolian Dust Samplers (ADS) were fixed to a 50m high steel tower above the ground at Minqin sand-dust source area in north-western China, dust was collected and treated respectively after each sand-dust storm event and end of the month in a year round. The vertical distribution of dust mass monthly and timely agreed the function of q(h)=a+bexp(-h/c), it showed that the dust particle concentration decays exponentially with the height. The correlation between dust mass and height was reasonably well. a, b and c were Coefficients, mainly driven by wind velocity, a and b positively increased with wind velocity, b was more obvious and sensitive than a, implying that the dust particle concentration decays more rapidly as wind velocity decreases. However, c decreased with wind velocity increasing and negative with a and b. The maximum and mean dust particle size was reduced with the height increase and varied with wind velocity. The standard deviation (sigma(I)) of dust particle size distribution had an increasing tendency with the height from poorly to very poorly sorted; all skewness (Sk(I)) was very positively fine skewed; kurtosis (K-G) had a reduced tendency with the height from very leptokurtic to leptokurtic. It all revealed that dust particles exists from local to remote areas extensively. Minqin is not only a main dust source area but also a main corridor of sand-dust storms in north-western China.

基于静宁沟壑区农户生产经营模式,对干沟乡境内及周边典型的农户系统,采用重点调查与一般调查相结合原则,对当地农户进行随机抽样和系统抽样的方法进行研究.对系统定量评价所应用的综合分析指标主要包括组分优势度和结构优势度以及复合生态系统稳定性指数.结果表明,短期来看,该区域内小农户占调查总户数的47%,中农户占调查总户数的31%,大农户占调查总户数的22%,从而得知调查区域内农户经济水平属于中等略偏低;对不同收入农户的生产经营模式比较可见,大农户家庭以苹果种植为主,其收益较为显著,占全年总收入的62.3%,且家庭总开支比重较小.长期来看,通过产业系统结构稳定性等方面综合分析,农户主要以苹果种植产业为主线,产业结构不够稳定,应改变农户生产系统原有单一经营模式,同时,结合市场需求和网络资源整合利用,促进苹果深加工等工副产业,发展形成复合经营模式,将对静宁丘陵沟壑区小尺度范围生态和经济的可持续发展产生直接并深远的推动作用.

Obj ective]Along the evolution direction from oasis to desert in the Minqin oasis-desert ecotone,the position and function of each species in the community composition among different segments were investigated and analyzed.The results could provide the basis for the regional de-sertification control and ecological restoration.[Method]From oasis to desert (northwest-south-east),line transect method was used to investigate the vegetation types,volume,crown breadth, height and ground diameter,etc.The important value and species diversity index were calculated.[Results]There were 23 species in different sections in the area,belonging to 10 families and 23 genera.There were 6 families 8 species in shrubs and 8 families 15 species in herbs.The largest important value of shrub (153. 48%)was the Nitrariatangutorum in the sandbags area.The Chenopodiaceaedominated herb layer.There were no obvious differences in the diversity of shrub and herb based on important value in the different stages.The H′,D and Dmc of shrub and herb decreased from oasis to desert transition.The Jsw value fluctuated due to individual advantage of Nitrariatangutorum.[Conclusion]In the study area,shrubs regeneration and growth was rela-tively stable.However,community structure was simple and species diversity was low.The growth of clonal plants,to some extent,accelerated the simplification of species diversity.

本研究通过调查民勤青土湖地区,不同年代退耕的盐碱化土地上植被的组成、结构、数量等群落学特征,旨在探索盐碱化退耕地上植被的演替规律.结果表明:盐碱化退耕地上首先入侵的是大量多年生草本植物和1年生草本植物,以后逐渐向灌木群落类型过度,直到形成相对稳定的灌木、半灌木群落.退耕初期以耐盐性草本植物占优势,随着退耕时间的延长,草本植物逐渐消减,群落向灌木类型发展,形成以黑果枸杞或黄毛头为主的单优群落,在部分区段形成黑果枸杞和黄毛头为共优种的群落类型.退耕初期物种丰富度、Simpson指数较高,随着退耕时间的延长,物种丰富度和Simpson指数均降低,最终达到相对稳定的状态;优势种群的生态优势度随退耕时间的变长而提高,反映了盐碱化退耕地上群落向单一化类型演替的趋势.由黑果枸杞或黄毛头为优势种形成的灌木群落是民勤盐碱化退耕地上形成的2种比较稳定的群落类型,其优势种(黑果枸杞、黄毛头)的密度分别为23100株hm2和31500株hm2.

Transpiration of plants has been one of the important issues of concern in plant physiological ecology and agricultural and forest science and related fields.In order to study the plant density by natural thinning and water nutrition area and water consumption of plant communitie in the natural state.This paper choice of several typical plant communities in the desert,and 4 years plots observations data are applied,and analyzed the characteristics of the water balance on plant communities that naturally sparse density,water nutrition area and water consumption of Artemisia arenaria,Ephedra przewalskii and Haloxylon ammodendron under the conditions of natural precipitation.The results showed as follows: natural sparse density of natural Artemisia arenaria and natural Ephedra przewalskii and artificial Haloxylon ammodendron is relatively stable in local.Water consumption of adult Haloxylon ammodendron forest is close with others in the same area with the 1.4 m water table in lysimeter and at 3 a seedlings.The density Haloxylon ammodendron is smaller than the others,with precipitation and transpiration,evaporation of the projection results.Under experimental conditions,the water consumption of a single plant does not mean the average water consumption of individuals in community.Water consumption of plant was studied in its natural state is more real than in the experimental conditions to a conclusion.Meaningful research is transpiration water consumption in the plant close to the wilting time,in respect of plant transpiration.Meaningful research is transpiration in plants close to the wilting time,in respect of plant transpiration,and not a few specific values,under certain water conditions.Artemisia arenaria,Ephedra przewalskii and Haloxylon ammodendron rely dieback to adapt to drought in rainfall is relatively low in the year.Some annual herbs will exit the community in the year is less precipitation,but they will enter the community in the the year in more precipitation.Artemisia arenaria will thrive when autumn rainfall is sufficient.However,the majority of seedlings of Artemisia arenaria natural death due to drought and winter difficult.Thus density of Artemisia arenaria,Ephedra przewalskii and Haloxylon ammodendron is relatively stable after natural thinning.

Regeneration experiments of degraded artificial Haloxylon ammodendron forest were conducted.It found that crust treatment can be modified to increase the depth of water infiltration in forest land,reduce the run-off,and increase the soil moisture.These effects have regeneration function for degraded Haloxylon ammodendron.In the three regenerated measures,including 100% crust-removed,50% crust-removed,100% broken crust,the optimal effect for soil moisture storge effect is 100% crust-removed and 50% crust-removed;the existence of the crust could easily lead to runoff;the soil crust breaking could prevent runoff and increase soil water infiltration;while precipitation is small,moisture changes mainly in the 0-20 cm soil layer;while precipitation is large,100% crust-removed and 50% crust-removed have significant strengthen effect.

Based on the analyses for agricultural production, status of land and water resources, regionalimited agricultural land resources, water shortages, single crop species, simple industrial structure, and small crop planting area severely restricted the development of regional ecological agriculture in the project area. In order to improve the ecological environment in oasis edge, develop the new cultivated agricultural oasis, improve land use efficiency, promote water-saving eco-agriculture, and increase regional economic benefits, some countermeasures were involved. They include trying to increase the planting area of economic plants and water-saving crops, developing quality forage and film mulching planting area, and expanding aquaculture. These countermeasures improved regional industrial planting structure, existing agricultural farming technology, ecological environment in oasis edge, and land use efficiency, enhanced soil fertility and received significant economic benefits, which would play the demonstration roles in the development of ecological agriculture and regional sustainable development of agriculture in the oasis edge.