云南红壤坡耕地的水土流失及其综合治理

在云南19.5°红壤坡耕地上设置水土流失综合治理试验样方,观测水土流失控制效果。结果表明,各观测样方的地表径流量、土壤流失和养分流失按照裸地(CK1)>传统单作玉米区(CK2)>植物篱玉米秸秆覆盖区>植物篱麻袋覆盖区>植物篱牧草活覆盖区依次降低。2004年较2003年降雨和径流明显增加,各处理土壤养分流失的增幅显著低于土壤流失的增幅;土壤养分流失与施肥量显著正相关;植物篱 覆盖区的养分利用率比传统单作玉米区极显著提高,养分利用率与施肥量负相关。植物篱麻袋覆盖区和植物篱牧草活覆盖区,地表径流减少22.7%~34.0%,土壤流失减少27.1%~67.6%,养分流失减少36.8%~77.8%,养分利用率提高27.9%~45.2%;保持水、土、肥和提高养分利用率的效果都优于植物篱秸秆覆盖区。     

东北黑土区植物篱土壤入渗性能研究

[目的]对东北黑土区植物篱种植模式的土壤渗透性进行研究,为黑土区坡耕地水土流失治理提供科学依据。[方法]通过小区试验开展研究。[结果]植物篱模式能够减小土壤容重,提高土壤孔隙度,显著增加土壤的入渗能力,进而减少水土流失;篱带部位的入渗能力大大高于篱间部位,不同品种植物篱渗透性能排序为:黑豆果短梗刺五加桑树,植物篱土壤入渗受地面坡度影响,小坡度的土壤入渗率高于大坡度。[结论]植物篱作为一种水土保持新措施,具有改善土壤结构,增加土壤入渗,减少地表径流,防治水土流失的作用,应在黑土区开展广泛的研究与推广。     

元谋干热河谷旱坡地复合生态农业模式效益研究初评

对元谋干热河谷区4种旱坡地生态农业模式进行连续2a的定位监测,研究各种模式的生态、经济和社会效益。结果表明:与对照模式罗望子+自然草被相比,建立的4种模式均有一定的培肥、改土效果,其中,以豆科牧草为主的罗望子+木豆、罗望子+木豆+柱花草、罗望子+木豆+绿肥3种模式的效果明显优于以禾本科牧草为主的罗望子+象草模式;4种模式均能在旱季提高土壤含水量,明显改善局地小气候;同时,产生良好的经济和社会效益。     

王东沟小流域土壤养分变化研究

通过2002年长武县王东沟小流域土壤养分测定，结合1982年长武县土壤普查中王东沟小流域养分普查数据及1993年CERN对王东沟小流域土壤养分普查数据进行分析，土壤有机质含量已经达到全国中等肥力水平，碱解氮，速效磷，速效钾的含量呈上升的趋势，但是氮磷养分比例不协调，成为限制农业生产的重要因素，该区域的土壤培肥途径是调整种植结构，增加养地作物的种植面积，增施有机肥，科学施用化肥。     

耐盐牧草籽粒苋对河西走廊草甸盐土改土培肥效应

在河西走廊草甸盐土上种植耐盐牧草籽粒苋,脱盐改土培肥效应十分明显。种植籽粒苋3~4年与CK比较,0~20 cm耕层全盐含量降低4.85~6.33 g kg-1,脱盐率达61.86~80.73%,pH降低0.35~0.40,土壤容重降低0.13~0.20gcm-3;总孔度增大4.91~7.55%,>0.25mm团粒结构增加18.51%~25.87%,自然含水量增加64.89~80.42g kg-1,土壤有机质、速效N、P、K亦随之增加。种植籽粒苋3年耕层全盐含量降到2.99g kg-1时,开垦后种植小麦、玉米、甜菜产量分别为5.96、11.25、56.36 t hm2。不同处理间的差异显著性经LSR检验达到显著和极显著水平。     

饲用型牧草东科“巨谷”改土培肥效应研究

在河西走廊盐土上种植饲用型牧草东科"巨谷",改土培肥效果明显。种植巨谷3年与CK比较,0～20cm土层中自然含水量增加99.72g kg-1、土壤贮水量增加171.78m3 hm-2、>0.25mm团粒结构增加22.64%、总孔度增加13.64%、毛管孔度增加8.05%、土壤容重降低0.23g cm3;pH由8.03降到7.79,全盐含量降低3.70 g kg-1,脱盐率达到70.34%;土壤有机质增加2.98 g kg-1、速效N、P、K分别增加14.74mg kg-1、2.26mg kg-1、37.26 mg kg-1。种植巨谷3年,平均株高265.25cm,茎粗3.80cm,单株鲜重1165.62g,单株干重384.65g,鲜草产量78.68t hm-2,干草产量25.96t hm-2,产值7300元hm-2。     

坡耕地植物篱在水土保持中的应用

 坡耕地植物篱种植模式是一种坡耕地可持续利用技术。结合已有研究成果,对坡耕地植物篱研究现状、效益等作了系统介绍。植物篱种植模式对改善土壤物理性质、提高土壤养分、减小坡耕地水土流失、防止土壤退化、促进农作物生长、增加作物产量、提供饲料、薪柴等方面具有良好的作用和效果,植物篱在坡耕地资源可持续利用中具有显著的生态效益和经济效益。对目前坡耕地植物篱认识上的问题及需要深入开展的工作进行了讨论,以促进我国植物篱技术和坡耕地整治的研究与发展。     

黄土丘陵区坡耕地土地退化研究

通过对人工种植黄花草木樨样地的监测，根据土壤养分含量的变化研究了改良退化土壤的效果。在种植黄花草木樨后，除了土壤全钾和速效磷含量下降以外，土壤有机质、水解性氮、全氮、全磷、速效钾养分含量皆明显增加。磷、钾下降的原因与黄花草木樨生长发育过程的需肥特性有关。在黄花草木樨生长发育过程中，应该注意追施磷、钾肥，可达到“以磷增氮”，“以钾促氮”的目的。实践表明，种植黄花草木樨这一技术具有改良土壤，培肥地力的作用，它是干旱、半干旱地区改良退化土壤的一种优良牧草。     

深耕培肥改良瘠薄黑土理化性质及提高大豆产量的研究

为明确深耕培肥对瘠薄黑土的改土效果,采用大田对比方法,以依安地区黑土为供试土壤,开展深耕培肥对瘠薄黑土土壤理化性质影响及对大豆产量的调查研究。结果表明:深耕培肥可以有效降低10~30 cm土层土壤容重、硬度,提高土壤通气性,容重第1年和第2年分别下降0.09 g cm~(-3)和0.05 g cm~(-3),通气系数分别提高为34.01×10~(-5) cm s~(-1)和10.89×10~(-5) cm s~(-1),10 cm以下土层土壤硬度与对照相比呈明显下降趋势;同时,深耕培肥后20~30 cm土层有效磷含量显著提高,两年增加幅度为15.05~16.23 mg kg~(-1);深耕培肥可以提高土壤速效钾含量,增加幅度为10.19~10.38 mg kg~(-1);并且深耕培肥提高了大豆产量,两年平均提高大豆产量达9.61%。     

不同草种治理模式对长汀县强度水土流失区的恢复效果分析

对比分析福建省长汀县强度水土流失区2种不同草种治理模式的生物多样性和土壤理化性质,评价不同草种治理模式的恢复效果。结果表明:草种治理模式极大地增加了长汀县强度水土流失区的生物多样性,改善了土壤物理性质,提高了土壤养分含量,特别是土壤的速效养分和有机质含量。草种治理模式中,以种植类芦草种的治理模式比以种植百喜草草种的治理模式效果更显著。     

Transformation of the Bryansk Paleosol in Microdepressions in the Center of the East European Forest-Steppe during the Maximum of Valdai Glaciation and in the Holocene

Eurasian Soil Science - Recent and Late Pleistocene soils of the central forest-steppe in the East European Plain have been studied. The main objective of the work is to reveal changes in the...     

Changes in the structure of the rhizosphere complex of actinomycetes in the ontogenesis of winter rye

Changes in the taxonomic structure of actinomycetes in the rhizosphere of winter rye (Secale cereale L.) growing on acid soddy-podzolic soil were studied. During the first stages of ontogenesis of winter rye, the rhizosphere complex of mycelial prokaryotes was characterized by a relatively level generic structure (with respect to the indices of abundance and frequency of particular genera), low values of the species diversity, and low domination frequency of the species from the Streptomyces genus. The numbers and species diversity of the streptomycetes increased during the further growth of the winter rye, so that streptomycetes became a dominant group in the complex of the rhizosphere actinomycetes. According to the two-way ANOVA, the population density of the Micromonospora and the Streptosporangium genera in the rhizosphere was mainly dictated by the winter rye variety, whereas the population density of the streptomycetes depended on the particular stage of the winter rye development. The differences between the actinomycetal complexes characteristic of different varieties of winter rye at the early stages of its development was leveled by the end of the winter rye growth.     

Evolution of forest pedogenesis in the south of the forest-steppe of the Central Russian Upland in the Late Holocene

The Late Holocene stage of forest pedogenesis has been studied on the interfluves along river valleys in the forest-steppe zone of the Central Russian Upland. The development of gray forest soils from the former chernozems as a result of the Late Holocene advance of forest vegetation over steppes is discussed. It is argued that the climatic conditions of the Subatlantic period were unstable, so that multiple alternation of forest and steppe vegetation communities took place. This specified a complex character of soil evolution upon contrasting substitution of forest pedogenesis for steppe pedogenesis. On the interfluves near the natural drainage network (balkas, ravines, and steep slopes of river valleys), the climate-driven dynamics of forest and steppe vegetation with corresponding changes in the character of pedogenesis could take place during the entire Holocene, which is reflected in a lower thickness of humus profiles and deeper leaching of carbonates from chernozems of the Early Iron Age in comparison with their analogues formed under steppe cenoses in central parts of the interfluves. Two variants of the evolution of gray forest soils can be suggested: the pulsating evolution typical of balkas and interfluves near river valleys and the continuous progressive evolution typical of automorphic (plakor) positions in central parts of the interfluves.     

Accumulation of chemical elements in the raised peatbogs of the subtaiga Trans-Urals in the Holocene

The results of studying the variability of the geochemical parameters of the layers of the Sartamskii upland peatbog in the south of Tyumen oblast based on the radiocarbon time scale are given. Four basic types of peat and stages of peat deposits formation in the Holocene are distinguished: the organomineral layer of the sediments in a paleolake (up to 5065 ± 60 years ago), the low moor layer (4300–4900 years ago), the transitional layer (3100–4300 years ago), and the high moor peat (250–3100 years ago). The upper peat layer (last 200–300 years) significantly differs from its main portion; in particular, it is characterized by an increased ash content and the accumulation of a number of elements. The relationship between the various characteristics of the deposit is analyzed using principal component analysis, and the conditions of the formation of the peat deposit in different time periods are estimated, including the climatic conditions (in relative units). The anthropogenic signal of the accumulation of some elements in wetland systems is identified.     

论图书馆数字馆藏资源建设中亟待解决的问题

论述数字馆藏的产生、概念和特点,分析数字馆藏资源建设中存在的问题,探讨数字馆藏资源建设中应采取的策略。     

Variations in the composition of the sap of zea mays with the increase in osmotic pressure of the nutritive solution

The alterations are studied which are produced in the content of mineral elements and organic fractions of sap with the increase in the osmotic pressure of the nutritive solution at levels of 2.0; 3.5 and 5.0 atm., obtained through the addition to the nutritive solution either of magnesium sulphate or PEG‐4000.

Through the effect of the osmotic pressure, the transformations are modified of the nitrogen and mineral phosphorus at organic fractions experience a series of modifications which produce different values in the Nm%TSN and Pm%TSP ratios with respect to control. Through action of the specific effect of magnesium sulphate, the reducing sugars concentrations in sap having an important increase.     

Seasonal changes in the communities of microorganisms and algae in the litters of tree plantations in the steppe zone

Specific structural and dynamic parameters of communities from various ecological and trophic groups of microorganisms and algae in the litter of artificial tree stands were studied using the example of the Staro-Berdyansky Forest in the steppe zone of Ukraine. The composition of the communities was shown to vary by seasons and depend on the forest-forming woody species. In spring, in all the litters, the maximal number of actinomycetes and aminotrophs was recorded; in the leaf litter, the number of phosphate-mobilizing organisms was also the largest. In summer, the development of cellulolytic organisms, ammonifiers, and nitrogen-fixers was intensified; in autumn, the number of micromycetes and oligotrophic organisms decreased. The composition of dominants, the species richness of algae and their abundance also varied by seasons. Representatives of the Chlorophyta division predominated. The highest species richness of algae was characteristic of the spring litter samples, and their number, for the spring and autumn ones. The positive correlation was established between the numbers of micromycetes and oligotrophs, micromycetes and algae. The negative correlation was found between the numbers of micromycetes and actinomycetes, cellulose-decompose bacteria and algae in the litters.     

Changes in the physical properties of soils in the Kamennaya Steppe under the impact of shelterbelts

The physical properties of ordinary chernozems and meadow-chernozemic soils under different land management practices (maple, larch, birch, and pine sections of the shelterbelts; continuous (since 1959) fallow; and arable field (since 1952)) were studied in the Kamennaya Steppe. The soils had favorable physicochemical properties, light clayey texture, and high microaggregation independently from the type of land management. The long-term impact of the shelterbelts improved the soil structure in the upper part of the humus horizon: the content of agronomically valuable aggregates increased, the content of coarse aggregates (>10 mm) decreased, the aggregation coefficient increased by 3.7–4.3 times, and the water stability of the aggregates became by 8–12% higher. The soils under the shelterbelts were characterized by minimum values of the bulk density and solid phase density and by maximum values of the total, active, and air porosities. At the same time, no considerable differences between water reserves in the studied range of soils were detected. The ratio of the optimum productive water range to the active (productive) water range (OPWR/AWR) within the upper soil meter varied from 0.42–0.44 to 0.45–0.54. This points to changes in the character of perched water: the content of intra-aggregate capillary-perched water decreases, and content of film perched water increases down the soil profile.     

近50年博斯腾湖水位变化特征分析

以干旱区博斯腾湖为研究对象,依据博斯腾湖1956—2012年期间的水位监测数据,采用小波分析及MannKendall(M-K)趋势检验等统计学方法,揭示了近50a博斯腾湖水位变化趋势及规律。结果显示:博斯腾湖1956—2012年水位变化分为3个阶段下降(1956—1987年)—上升(1988—2002年)—下降(2003—2012年),其中1956—1987年水位下降了3.39m;1988—2002年上升了3.7m;2003—2012年再次下降了3.21m。水位总体上呈现出显著的下降趋势,且通过了α=0.05时的显著性检验。就其周期性变化规律而言,博斯腾湖水位存在18a的主周期,而38a的周期由于水位资料序列有限难以确定,需要更长的资料序列进行分析验证。     

Quality of used-snow discharged in the ST-Lawrence river,in the region of the Montreal Harbor

Snow disposal creates problems each year in Montreal. Snow dumping in water courses is favored due to both esthetic and economic considerations. Used snow must be considered as a potential pollutant. Its impact on the aquatic receiving environment is not well known. With river dumping in progress, snow samples were collected at 3 sites: Concorde Bridge, and at piers 30 and 52 in Montreal Harbor. Analysis of 28 routine parameters demonstrated that the quality of snow ultimately dumped in the river varies considerably according to its sources and the time it remains in the streets. Used-snow from residential areas was shown to be less polluted than the snow from commercial areas. Furthermore, from the total number of sampled districts, used-snow dumped at pier 30 appears to be relatively more polluted as it originated from downtown areas where vehicle circulation is more dense. Heavy metals in particles sizes between 0.45 and 63 μm represented more than 70% of the measured suspended solids which reflects the risk of bioaccumulation via benthic organisms. Principal component analysis of present data suggests that with analysis of chlorides, suspended solids and Pb alone, it is possible to approximately determine the quality of used-snow.