Black Soil Area Research Articles

Elevated Risk of Ecological Land and Underlying Factors Associated with Rapid Urbanization and Overprotected Agriculture in Northeast China

Ecological land with considerable ecological value can be regarded as an important indicator in guaranteeing ecosystem function and sustainable development. Generally, the urbanization process has been considered to be the primary factor affecting ecological land use. However, the influence of agricultural development, particularly in a typical farming area, has rarely been studied. In this paper, we present a method to assess the ecological risk of ecological land (ELER) in a black soil area in northeastern China. Furthermore, the underlying factors were detected using the geographically weighted regression model, which took into account conditions of natural elements, the urbanization process, and grain production conditions. The results indicate that ecological land experienced remarkable changes with an evident loss and decline from 1996–2015. The ELER progressively increased in the concentrated farming area and the western agro-pastoral ecotone, and the ecological land in the eastern forest area was always at a high risk level. According to the regression coefficients, the relationships between influence factors and ELER could be better explained by the variables of elevation, slope, proportion of rural residential area, and ratio of cultivated land area to residential area. To summarize, agricultural occupation and urban expansion were verified as the two main causes of ecological land loss, as well as elevated risks. In light of the current situation, measures such as policy adjustment and ecological restoration should be taken to avoid risk and optimize land use.

Effect of soybean roots and a plough pan on the movement of soil water along a profile during rain

The movement of water into soil is the primary driving force in nutrient transport for crops, and the laws governing this movement can be affected by crop roots and plough pans. The main objectives of this study were to monitor the movement of water during rain along a soil profile influenced by soybean roots and a plough pan and to assess whether these factors influenced the efficacy of using the Richards equation to simulate the transport of soil water along a profile associated with a single rain. Experiments and model simulations were carried out. Our results suggested that the soybean field soil may have had preferential flow paths. Soybean stems and leaves transferred rainwater that otherwise would have fallen farther from the central stalk. The transmission of rainwater by the branches and leaves had a larger effect than the interception of rainwater by the branches and leaves. The effect of the root system on the soil particles may increase soil capillary action and ultimately increase saturated hydraulic conductivity. Saturated hydraulic conductivity was higher near the surface than at depth, because the transmission of water by the root system and the effect of large gaps were greater in the soil near the surface. Saturated hydraulic conductivity for both bare land and land covered with soybean plants decreased linearly from depths of 0–15 cm along the soil profile, particularly in the presence of a plough pan. We developed a linear equation to represent the variation in saturated hydraulic conductivity in the 0–15-cm layer in the black soil area of northeastern China. Using our linear model for saturated hydraulic conductivity as a parameter, the Richards equation more accurately simulated soil water transport along a profile influenced by soybean roots and a plough pan in rainy conditions.

Soil Carbon Stock in Non-traditional Black Soils of North Eastern India: Tripura as Example

Tripura state in the north-eastern region (NER) of India, by its geographic location and richness in biodiversity, well supported by complementary climatic factors, more particularly high rainfall for luxuriant phyto-biomass (both above and below ground) in the form of forests and allied sources of vegetation, are known as non-traditional black soil area. Studies conducted on the soils of Tripura indicate that about 18.20 per cent area of the State consists of black soils. The study attempts to identify the important factors responsible for the formation of black soils even in the non-traditional black soil area of the north-eastern region in general and Tripura state in particular. These black soils are deep to very deep and are mostly dominated by smectitic clays. Such soils resembled the Vertisols mapped elsewhere in other parts of the country concerning texture, periodical opening and closing of cracks and subsurface colour but have dissimilarity for slickenside development, wedge-shaped structure and colour on the surface. The CEC of these soils indicate the dominance of low-activity clays (LAC). However, the clay CEC of these soils are more than 30 and it has been extended up to 60, indicating mixed mineralogy and dominance of smectites or hydroxy interlayered smectites in the clay fraction, which holds more nutrient and moisture and thus converts these areas as the granary of the State. Therefore, besides the dominating effect of humid climate with cooler winter months with profuse vegetation, the soil substrate quality (quality and quantity of expanding clay minerals) is of fundamental importance in the sequestration of OC in the soil. The study indicated that within the 0-30 cm soil depth, black soils of Tripura has got the capabilities to store 0.01Pg soil organic carbon stock which is about 20 per cent of the SOC stock of whole Tripura and 0.01 per cent of SOC stock of India. These soils are more fertile, holding more nutrients and moisture and are still in the weathering stage and show the presence of HIS and HIV in their mineralogical makeup. Therefore, the present information will be helpful for developing appropriate land use plans and conservation planning to ensure the green belt in northeastern India in general and Tripura state in particular to protect natural ecosystems.

玉米秸秆还田量对黑土区农田地面节肢动物群落的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 玉米秸秆还田量对黑土区农田地面节肢动物群落的影响 DOI: 10.5846/stxb201712062198 作者: 作者单位: 内蒙古农业大学,内蒙古农业大学,内蒙古农业大学,内蒙古农业大学,内蒙古农业大学,内蒙古农业大学,扎赉特旗农业技术推广中心,兴安盟土壤肥料和节水农业工作站 作者简介: 通讯作者: 中图分类号: 基金项目: 农业部黑土地保护与利用项目 Impact of quantity of returned corn straw on the cropland ground arthropod community in a black soil area Author: Affiliation: Inner Mongolia Agricultural University,Inner Mongolia Agricultural University,,,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为考察玉米秸秆还田量对黑土区农田地面节肢动物群落的影响，2016年6-9月在内蒙古兴安盟扎赉特旗研究了0（CK）、9000（SR1）、10500（SR2）、12000（SR3）、13500（SR4）kg/hm2 5个梯度对农田地面节肢动物群落影响。结果表明：共捕获地面节肢动物1820只，隶属于16个类群；SR4处理显著提高了地面节肢动物个体数（P < 0.05），SR3处理显著提高了地面节肢动物类群数（P < 0.05）。各处理样地地面节肢动物个体数最高值均出现在8月，类群数则出现在7月；SR4处理显著提高了地面节肢动物多样性指数和丰富度指数（P < 0.05），SR1处理显著提高了地面节肢动物优势度指数（P < 0.05），对照CK的均匀度指数最高（P > 0.05）。相关分析表明：农田地面节肢动物的个体数与土壤有机质呈极显著相关（P < 0.01），与平均入渗率呈显著正相关（P < 0.05），与土壤容重呈显著负相关（P < 0.05）；类群数与土壤温度呈显著正相关（P < 0.05）；丰富度指数与平均入渗率和土壤含水量呈显著正相关（P < 0.05）。主成分分析表明：地面节肢动物的个体数、多样性指数、蟋蟀总科、跳甲科和步甲科5个特征指标对玉米秸秆还田最为敏感，初步认为是衡量黑土区土壤玉米秸秆还田后肥力状况的评价指标。 Abstract:In order to understand the effects of returned corn straw on the cropland ground arthropod community in a black soil area, an experiment with five different amounts of corn straw returned to the field 0 (CK), 9000 (SR1), 10500 (SR2), 12000 (SR3) and 13500 (SR4) kg/hm2 was carried out in Zhalaid Banner of Inner Mongolia from June to September 2016. The results showed that 1820 ground arthropod individuals were captured and these were classified into 16 taxonomic groups. The number of individuals of ground arthropods was significantly increased in SR4 (P < 0.05), and the number of taxonomic groups was significantly increased in SR3 (P > 0.05). The number of individuals of ground arthropods was highest in August, and the number of taxonomic groups of ground arthropods was highest in July. The diversity and richness indexes were highest in SR4 (P < 0.05). The dominance index was highest in SR1 (P < 0.05). The evenness index was highest in CK (P < 0.05). Correlation analysis showed that ground arthropod individuals were not only positively correlated with soil organic matter (P < 0.01), but also with average infiltration rate (P < 0.05), and negatively correlated with soil bulk density (P < 0.05). Soil temperature was obviously correlated with the number of ground arthropod taxonomic groups (P < 0.05). The richness index was obviously correlated with average infiltration rate and soil moisture content (P < 0.05). Principal component analysis (PCA) showed that ground arthropod individuals, the diversity index, and the taxa Grylloidea, Alticinae and Carabidae were most sensitive to the amount of straw returned, and could therefore be considered as evaluation indexes to judge the nutrient status after straw is returned in a black soil area in the future. 参考文献 相似文献 引证文献

One-time root-zone N fertilization increases maize yield, NUE and reduces soil N losses in lime concretion black soil

Excess N-fertilizer application and inappropriate fertilization methods have led to low N use efficiency (NUE) and high N leaching. A field experiment was performed in a typical lime concretion black soil area to compare N application methods: split surface broadcasting (SSB) and one-time root-zone fertilization (RZF) on grain yield, NUE, the fate of 15N urea and soil N loss during the 2015 and 2016 maize growing seasons. Each application method was tested at N rates of 135 and 180 kg N ha−1, and a control (CK) with no N fertilizer. The RZF treatment remarkably increased grain yield by 7.0% compared with SSB treatment under 180 kg N ha−1, and significantly increased N derived from fertilizer by 28.5%. The residual 15N in the 0–80 cm soil layer was 40.6–47.6% after harvest, 61.8–70.9% of which was retained in 0–20 cm. The RZF remarkably increased the 15N recovery in maize by 28.7%, while significantly decreased the potential N losses by 30.2% compared with SSB in both seasons. In conclusion, one-time RZF of urea is recommended for obtaining high yields, increasing NUE, and minimizing N losses in maize, which deserves more attention for developing and applying in the future.

A Review on Trends in Ground Improvement Techniques

Abstract Ground improvement is frequently known as an innovative technique of the amendment of soil in foundation to deliver better effectiveness under design and/or operational loading conditions at the several construction sites. Ground improvement changes soil characteristics there by allowing different types of construction procedures. An enhancement of soft ground deposits near the coastal areas, black and delta soil areas of the country has been the contest for infrastructural development. Rapid urban and industrial growth demands more land for further development. In order to meet this demand, reclamation and utilization of inappropriate and environmentally affected lands have been taken up. These inoperative lands for construction have been reformed to useful ones by accepting one or more ground improvement techniques. A wide range of techniques have been employed for the load settlement response of weak soil deposits. The field of ground improvement technique is rapidly expanding. It requires lots of investigation and monitoring some of the field problems related to compaction characteristics and feasibility of construction material. The present paper gives the overview and concept of recent major ground improvement techniques and discusses their practical applications. Keywords: Compaction, monitoring, ground improvement, environmentally, construction Cite this Article Siddarth Singh. A Review on Trends in Ground Improvement Techniques. Journal of Geotechnical Engineering . 2018; 5(1): 18–22p.

The functions of soil water and heat transfer to the environment and associated response mechanisms under different snow cover conditions

This study investigates the response mechanisms between soil water-heat transfer and environmental factors during freeze-thaw periods and establishes soil water-heat transfer functions in a cold region. Based on field-measured values of soil temperature and liquid-phase water content collected at an automatic weather station in the black soil area of the Songnen plain, the influence of the cumulative negative temperature on the soil freezing depth was analyzed under different snow cover conditions. A gray correlation analysis method was used to screen the environmental factors and determine those with the most influence on changes in soil water-heat transfer processes. Then, soil water-heat transfer functions were established between the selected environmental factors and soil temperature, the liquid-phase soil water content. The results showed that during the freezing and thawing period, snow cover hindered the effects of the cumulative temperature on the thickness of the frozen soil layer. Additionally, the time of occurrence of the maximum freezing depth under natural snow (NS), compacted snow (CS) and thickened snow (TS) treatments was delayed 7, 12 and 20 days, respectively, compared with that under bare land (BL). The correlation between atmospheric temperature, total radiation and soil temperature was relatively high, and this effect decreased with the increasing of snow cover. The main driving factors of variations in the liquid-phase water content were ambient humidity and saturated vapor pressure, and the effects of these factors decreased with increasing soil depth and snow cover thickness, similarly. In the active frozen layer, the correlation coefficients of the soil water-heat transfer functions were relatively high, and the function model can be tested by the significance (P < 0.05) test. However, the R2 values of functions below the active layer were relatively low, and the soil water-heat transfer in the area below the active layer was less affected by the environment. This study reveals the characteristics of energy transfer and mass transfer in a composite system of atmospheric factors and frozen soil under snow cover conditions. It provides a reference for accurate forecasting and the efficient utilization of soil water and heat resources in cold and arid regions.

Responses of accumulation-loss patterns for soil organic carbon and its fractions to tillage and water erosion in black soil area

Tillage and water erosion have been recognized as the main factors causing degradation in soil organic carbon (SOC) pools of black soil. To further explore the response of SOC and its fractions to different driving forces of erosion (tillage and water), geostatistical methods were used to analyze spatial patterns of SOC and its three fractions at a typical sloping farmland based on tillage and water erosion rates calculated by local models. The results showed that tillage erosion and deposition rates changed according to the slope positions, decreasing in the order: upper-slope > lower-slope > middle-slope > toe-slope and toe-slope > lower-slope > middle-slope > upper-slope, respectively; while the order of water erosion rates decreased in the order: lower-slope > toe-slope > middle-slope > upper-slope. Tillage and water erosion cooperatively triggered intense soil loss in the lower-slope areas with steep slope gradient. Tillage erosion could affect C cycling through the whole slope at different levels, although the rate of tillage erosion (0.02-7.02 t·hm-2·a-1) was far less than that of water erosion (5.96-101.17 t·hm-2·a-1) in black soil area. However, water erosion only played a major role in controlling C dynamics in the runoff-concentrated lower slope area. Affected by water erosion and tillage erosion-deposition disturbance, the concentrations of SOC, particulate organic carbon and dissolved organic carbon in depositional areas were higher than in erosional areas, however, microbial biomass carbon showed an opposite trend. Tillage erosion dominated SOC dynamic by depleting particulate organic carbon.

Gully erosion regionalization of black soil area in northeastern China

Gully erosion is the frequent and main form of soil erosion in the black soil area of the northeastern China, which is one of the most important commodity grain production bases in China. It is encroaching upon the fertile farmland there. Regionalization of gully erosion can reveal the spatial distribution and regularity of the development of gully erosion. Based on the eco-geographical regional background features of the black soil area, this study combined the regionalization with influencing factors of the development of gully erosion. GIS spatial analysis, geostatistical analysis, spatial statistics, reclassification, debris polygon processing and map algebra methods were employed. As a result, the black soil area was divided into 12 subregions. The field survey data on type, length, volume and other characteristics indicators of gully erosion were used to calibrate the results. Then the features of every subregion, such as where the gully erosion is, how serious it is, and why it happens and develops, were expounded. The result is not only an essential prerequisite for gully erosion surveys and monitoring, but also an important basis for gully erosion prevention.

秸秆还田对耕作黑土中小型土壤动物群落的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 秸秆还田对耕作黑土中小型土壤动物群落的影响 DOI: 10.5846/stxb201511202350 作者: 作者单位: 哈尔滨师范大学地理科学学院,哈尔滨师范大学 地理科学学院,哈尔滨师范大学地理科学学院,哈尔滨师范大学地理科学学院,哈尔滨师范大学地理科学学院,哈尔滨师范大学地理科学学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41371072，41471037）；黑龙江省普通本科高等学校青年创新人才培养计划（UNPYSCT-2015054）；哈尔滨师范大学校青年学术骨干项目（10XQXG08） Effect of straw-returning management on meso-micro soil fauna in a cultivated black soil area Author: Affiliation: College of Geographical Science,Harbin Normal University,Key Laboratory of Ｒemote Sensing Monitoring of Geographic Environment,College of Heilongjiang Province,,,College of Geographical Science,Harbin Normal University,Key Laboratory of Ｒemote Sensing Monitoring of Geographic Environment,College of Heilongjiang Province,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为了考察秸秆还田对耕作黑土中土壤动物群落结构的影响，2009年到2011年在黑龙江省海伦市进行了定点实验，调查了样地A（17 kg秸秆+含高浓度催腐剂还田）、样地B（8.5 kg秸秆+含低浓度催腐剂还田）、样地C（对照样地），样地D（8.5 kg秸秆还田），样地E（17 kg秸秆还田）的中小型土壤动物群落结构。共获取中小型土壤动物21779只，分别隶属于58个类群。其中，甲螨亚目、姬跳虫科、棘跳虫科与驼跳科4个类群土壤动物在本地区是最适应环境变化的土壤动物类群。土壤动物群落结构分析表明，对照样地C中土壤动物密度最高（46591.67只/m2），土壤动物类群最多（17.17），土壤动物优势度指数最大（0.37），样地D中土壤动物丰富度指数最多（2.63），样地A中土壤动物多样性指数最高（1.72），样地B中土壤动物均匀性最高（0.64）。同时，各样地土壤动物基本都具有表聚性，样地A中土壤动物更趋于生存于上层土壤。综合比较分析表明，样地A秸秆还田方式相对来说最利于土壤动物生存。主成分分析表明，不同秸秆还田方式对土壤动物密度、甲螨亚目动物类群、节跳虫科类群、前气门亚目类群影响较大，是耕作黑土中对秸秆还田方式反应敏感的土壤动物指标，今后可以作为考察耕作黑土秸秆还田肥力效应的评价指标。另外，CAA分析表明：受土壤环境因子影响较大的土壤动物类群多为研究区域内优势类群与常见类群，土壤动物的密度与土壤中有机质、有机碳、碳氮比与全磷的含量关系最为密切。 Abstract:Crop straw is an important material basis for nutrient cycling in agro-ecosystems. Straw returning is a method in which straw is applied to the soil to improve soil properties, and is used for accelerating immature soil development in cultivated land and improving soil fertility. Soil fauna is an important component of the ecosystem, and is involved in the straw decomposition process, improving the decomposition of organic matter and promoting nutrient absorption by plants. Therefore, research on the ecology of soil fauna and sustainable utilization of cultivated soil, including black soil, has been widely conducted. Understanding the correlation between soil fauna and straw returning will provide a scientific basis for the protection of the soil fauna community and sustainable utilization management of tillage ecosystems in black soil areas. To investigate the effect of straw returning on meso-micro soil fauna communities in cultivated black soil, field experiments were carried out in Hai-lun, Heilongjiang Province from 2009 to 2011. The experiments were conducted in five selected plots:Plot A:17 kg corn straw returning and high concentrations of microbial inoculants; Plot B:8.5 kg corn straw returning and low concentrations of microbial inoculants; Plot C:control; Plot D:8.5 kg corn straw returning; and Plot E:17 kg corn straw returning. A total of 21,779 individuals, belonging to 58 groups, were extracted and identified in the plots. Among them, Oribatida, Hypogastruridae, Onychiuridae, and Cyphoderidae were most suitable to understand environmental changes in the study area. Analysis of the soil fauna community structure showed that the density, group number, and Simpson Dominance Index of soil fauna were highest in the control Plot C (46,591.67 ind/m2, 17.17, 0.37, respectively). The soil fauna richness index was highest in Plot D (2.63); the diversity index was highest in Plot A (1.72); and the evenness index was highest in Plot B (0.64). Meanwhile, the soil fauna was characterized by surface accumulation in the experimental plots. The group numbers of dominant soil fauna in Plot A in all soil layers were lower than those in other plots, and soil fauna was more dominant in the upper layer of the soil. Together, the method of straw returning in Plot A was the most productive for soil fauna. In addition, the results of a Principal Component Analysis (PCA) indicated that different methods of straw returning had a considerable effect on soil fauna density. Oribatida, Isotomidae, and Prostigmata were sensitive soil fauna that responded to different methods of straw returning, and could therefore be considered as an evaluating index to investigate the fertility effect of straw returning in cultivated black soil in the future. The results of the Canonical Correspondence Analysis (CCA) indicated that the dominant and common groups of soil fauna were considerably influenced by the soil environment, and the density of soil fauna was closely associated with organic matter, organic carbon, the carbon to nitrogen ratio, and total phosphorus in the soil. 参考文献 相似文献 引证文献

Site-specific management zone of field scale based on remote sensing image in a black soil area

Site-specific management zone of field scale based on remote sensing image in a black soil area

Effects of Combined Application of Nitrogen and Potassiumon on Yield and Nutrient Accumulation of Wheat in Huaibei Lime Concretion Black Soil Area, China

Effects of Combined Application of Nitrogen and Potassiumon on Yield and Nutrient Accumulation of Wheat in Huaibei Lime Concretion Black Soil Area, China

Die Wiedergeburt der Ethnologie aus dem Geist des Atheismus. Zur Erforschung des „zeitgenössischen Sektierertums“ im Rahmen von Chruščevs antireligiöser Kampagne

In the summer of 1959, researchers belonging to the Academy of Sciences began to conduct fieldwork in Russia’s Central Black Soil Area. They dedicated themselves to an issue that was for various reasons quite sensitive: “religious sectarianism”. In the context of the anti-religious campaign launched by Nikita Khrushchev, this research was, on the one hand, intended to scientifically underpin state propaganda. On the other hand, the research team headed by the ethnographer and specialist of religion, Aleksandr Klibanov, had to deal with the problem of how - as atheists on a state mission - to attain reliable information from their interview partners. As members of “sects”, the latter were regarded as potentially “subversive” and thus subject to persecution. In the field, the researchers thus developed forms of participant observation whose results were greatly appreciated by the state, but methodologically criticized as extremely questionable and unworthy of Party and Komsomol members. In this article, an exploration is made of the interplay between the various State, Party and scientific institutions as well as the interaction between Moscow and the regions where the research was conducted. This allows to identify important elements in the political framework of scientific work and methodological self-reflection within Soviet ethnography during the Thaw period.

Comparison of sampling schemes for the spatial prediction of soil organic matter in a typical black soil region in China

Data on the spatial distribution of soil organic matter (SOM) are important for the spatio-temporal modeling of soil organic carbon dynamics and soil carbon sequestration potential estimates. A total of 175 topsoil samples (0–20 cm) were collected from a typical black soil area in central Hailun County in northeastern China. Seven sampling design schemes, ordinary kriging (OK), and regression kriging (RK) were applied to the re-sampled SOM data for predicting the spatial distribution of SOM. The results showed that single sampling designs, such as simple random, stratified random (STR), and conditional Latin hypercube (CLH), produced poor estimates of SOM, while hybrid sampling designs, such as uniform distribution of point pairs for variogram estimation combined with spatial coverage, STR combined with spatial coverage (STRC), and CLH combined with spatial coverage (CLHC), had a higher predicting accuracy when the sample size was relatively small (≤262). For square grid sampling, a higher predicting accuracy could be achieved only when the sample size was sufficiently large (i.e., ≥402). The inclusion of prior knowledge or SOM-related secondary data in the sampling design and the trade-off between the even and uneven distribution of sampling points are especially important for designing a small-size sampling scheme. Moreover, although the SOM-predicting accuracy of RK was not as good as OK in this study, increasing the sample size may improve the predicting accuracy of SOM. Therefore, the optimal sampling design and spatial predicting method are both important for the predictive mapping of SOM spatial distribution in this area.

Three Decades of Geosynthetics in India

With the recent emphasis on infrastructure development, geosynthetics in India have received a tremendous boost. Apart from the consistent use in pavements of the east-west and north-south corridors and golden quadrilateral of the NHDP projects being executed by the NHAI, reinforced soil walls in urban flyover approaches have become common, due to their distinct advantages over conventional reinforced concrete walls. These apart, the use of high strength geotextiles and geocell mattresses for foundation of high embankments on soft soils has also proven to be feasible even in black cotton soil areas. Increasing emphasis is being given to the development and use of natural fibre (particularly, jute and coir) geotextiles for civil engineering applications. The paper traces many of these developments and summarizes the key issues to be taken note of for utilizing the vast potential geosynthetics offer, in India's march to development.

The Research Progress of Agricultural Non-Point Source Pollution in the Black Soil Area of Northeast China

A large area of agricultural non-point source pollution which was caused by higher input of fertilizer and pesticide, lower availability of fertilizer, soil erosion and serious destruction of ecological balance in black soil region of northeast China has attracted the national attention and raised the relevant scholars’concern. This paper mainly summarizes the research on mechanism exploration, quantitative of pollution load and model simulation and controlling measure of the black earth region of northeast conducted by domestic scholars, which based on the instruction of general situation of agricultural non-point source pollution in black soil region of northeast China, and then put forward the shortcomings in the present study and direction of future development.

Quantifying yield gaps in wheat production in Russia

Crop yields must increase substantially to meet the increasing demands for agricultural products. Crop yield increases are particularly important for Russia because low crop yields prevail across Russia’s widespread and fertile land resources. However, reliable data are lacking regarding the spatial distribution of potential yields in Russia, which can be used to determine yield gaps. We used a crop growth model to determine the yield potentials and yield gaps of winter and spring wheat at the provincial level across European Russia. We modeled the annual yield potentials from 1995 to 2006 with optimal nitrogen supplies for both rainfed and irrigated conditions. Overall, the results suggest yield gaps of 1.51–2.10 t ha−1, or 44–52% of the yield potential under rainfed conditions. Under irrigated conditions, yield gaps of 3.14–3.30 t ha−1, or 62–63% of the yield potential, were observed. However, recurring droughts cause large fluctuations in yield potentials under rainfed conditions, even when the nitrogen supply is optimal, particularly in the highly fertile black soil areas of southern European Russia. The highest yield gaps (up to 4 t ha−1) under irrigated conditions were detected in the steppe areas in southeastern European Russia along the border of Kazakhstan. Improving the nutrient and water supply and using crop breeds that are adapted to the frequent drought conditions are important for reducing yield gaps in European Russia. Our regional assessment helps inform policy and agricultural investors and prioritize research that aims to increase crop production in this important region for global agricultural markets.

Research on the Evaluation and Forecast of Spatio-Temporal Variability of Soil Fertility in Black Soil Area of SongLiao Plain

Research on the Evaluation and Forecast of Spatio-Temporal Variability of Soil Fertility in Black Soil Area of SongLiao Plain

Temporal variations of ecological security with soil and water loss stress in black soil region of northeast China: a case study on Baiquan County

The deterioration of ecological situation with serious soil and water loss in black soil region of northeast China has attracted more attention due to its significant role on food security of China. To investigate the temporal characteristics of ecological status in typical black soil areas, Baiquan County is selected. Based on the model of Press-Status-Response (P-S-R), indicators are established and the ecological security situations with soil and water loss of Baiquan County are evaluated for the years of 1979, 1990, 2000 and 2005. The results show that the ecological insecurity indicator changes from 0.701 to 0.435 from 1979 to 2005, with a decrease of 37.9% for Baiquan County. And the contributions of physical and human factors to the temporal variations of the ecological security are discussed in detail. Moreover, several problems are recognized to be the potential threats to the ecological security in Baiquan county, including reduction of the effective thickness, excessive application of the fertilizer and low efficiency of the agricultural irrigation system. It is found that effective soil and water loss control actions have made great contribution to the improvement of the ecological security in Baiquan county. All these results and discussions are very helpful for the further investigation on the quantitative relationship between soil and water loss and ecological security in black soil region of northeast China.

Community structure of soybean plant growth-promoting rhizobacteria in the black soil region of Northeast China

为明确东北黑土区大豆根际促生菌的群落组成, 选择内蒙古自治区鄂温克族自治旗、黑龙江省海伦市、黑龙江省克山县和黑龙江省农垦红兴隆农场 4 个采样点, 分析了大豆根际自生固氮菌、解磷菌、溶磷菌和硅酸盐细菌的群落组成, 解析了促生菌种与地域之间的对应关系。 结果表明: 东北黑土区的大豆根际土壤中存在大量促生菌, 自生固氮菌达到 104 cfu·g^?1, 溶磷菌和解磷菌达到 105 cfu·g^?1, 硅酸盐细菌达到 103 cfu·g^?1; 分离得到具有自生固氮能力的菌株 5 株, 溶磷菌 6 株, 解磷菌 7 株, 硅酸盐细菌 4 株; 自生固氮菌多样性指数在 0.94~1.60 之间, 溶磷菌多样性指数在 0.83~1.52 之间, 解磷菌的多样性指数在 1.07~1.67 之间, 硅酸盐细菌多样性指数在 0.52~0.96 之间, 4 个取样点大豆根际促生菌的多样性指数均大于 2。 采用对应分析确定了不同地区的典型促生菌, 内蒙古鄂温克族自治旗的特征种为自生固氮菌 LLN8 (<i>Azotobacter beijerinckia indica</i>), 黑龙江省海伦市的特征种为溶磷菌 DHS13 (<i>Micrococcus</i>), 黑龙江省克山县的特征种为溶磷菌 DHS19 (<i>Pseudomo-nas</i>), 黑龙江省红兴隆农场的特征种为自生固氮菌 LLN1 (<i>A. chrooco-ccum</i>)和溶磷菌 DHS5 (<i>Azotobacter</i>)。同 时明确了 LLN2 (<i>A. azomonas</i>)、LLN6 (<i>Bacillus mucilaginosus</i>)、DHS9 (<i>Arthrobacter</i>)、DHSO2 (<i>Pseudomonas</i>)、DHSO14 (<i>Erwinia</i>)、DHSO17 (<i>Corynebacterium</i>)和 LSJ21 (<i>Bacillus</i>)在东北黑土区大豆根际分布较为广泛, 这些菌株为研发中国东北黑土区大豆专用型复合生物肥料提供了基础条件。