共查询到20条相似文献，搜索用时 46 毫秒
1.
土壤动物在农业生态系统中的研究进展 总被引：17，自引：1，他引：17
近些年来随着对生态学的深入研究,人们认识到土壤动物的群落结构、功能以及在生态过程中积极的不可替代的作用,土壤动物逐渐成为生态学研究的热点之一。本文分析评价了国内关于土壤动物的研究进展。同时对国外土壤动物在土壤环境评价、凋落物分解、土壤健康的指示作用、与污染环境的关系、二氧化碳浓度对其的影响、在农业生态系统中的作用、在城市生态系统研究中的作用、在废弃物处理及土壤改良中的应用、在N循环中的作用、湿地土壤动物研究等10个方面的研究动态进行了综述。并提出了对土壤动物研究工作的几点建议。 相似文献
2.
慈溪市土壤系统分类研究 总被引：6，自引：0，他引：6
本文对浙江省慈溪市第二次土壤普查土壤分类系统进行了修订,并建立了慈溪市土壤系统分类,依据浙江省土系建立的原则和要求,初步建立了慈溪市土壤的土族和土系。 相似文献
3.
城市化过程对土壤资源影响研究进展 总被引：2，自引：0，他引：2
世界范围内的快速城市化过程对土壤资源的质与量都产生了深刻影响.作为一种不可再生性自然资源,土壤在我国快速城市化过程中的强烈人为活动影响下发生功能上的转化、弱化甚至消失.城市及其周边地区的土壤景观、各种土壤过程都明显异于传统的土壤质量演变规律.与农业生态系统相比,城市生态系统更加复杂,城市化过程中土壤演变研究的挑战性也更大.深入开展城市化过程中土壤质、量响应及其生态环境效应的系统研究意义重大. 相似文献
4.
土壤时空变化研究的进展与未来 总被引：10，自引：4，他引：6
理解和表征土壤的时空变化是土壤学的基本任务,也是评估和合理发挥土壤功能的重要前提。土壤的时空变化与气候环境变迁、岩石圈风化、地表物质迁移、生物地球化学循环等圈层变化过程相耦合。围绕土壤时空变化研究的新近进展,本文综述并展望了土壤形成和演变过程、土壤形态学、土壤调查、土壤分类、数字土壤制图与土壤退化的发展态势。未来土壤时空变化研究的关键科学问题主要包括:地球表层系统中土壤与环境要素之间的多过程耦合机理与模拟、多尺度土壤-环境关系与模拟、多元土壤信息的融合机理与数据同化。未来重点研究领域将涉及到关键带科学引领的土壤形成和演变研究、多尺度数字土壤制图与时空变化预测、基于多传感器的土壤综合观测原理与技术、完整和详尽的国家和全球土壤资源清单及共享平台建设、区域土壤资源退化机理及其功能恢复。 相似文献
5.
四种土壤管理方式对李园土壤微生物和土壤酶的影响 总被引：11，自引：0，他引：11
通过2003~2004两年的试验发现,刈割覆盖、刈割压埋、畜粪还园三处理纤维分解菌和硅酸盐细菌的数量均明显高于清耕处理(对照),且两种微生物数量均以夏季最多,秋季次之,春季再次,冬季最少。前三处理蔗糖酶、脲酶、过氧化氢酶、纤维分解酶、多酚氧化酶的酶活性都较清耕有显著或极显著提高;各处理酶活性也以夏季最高、秋季次之,春季再次,冬季最低。2004年刈割覆盖、刈割压埋两处理蔗糖酶、脲酶、过氧化氢酶活性较2003年有显著或极显著增加,畜粪还园、清耕两处理三种酶活性两年间差异很小。经相关性分析还发现,纤维分解菌除与脲酶相关性不显著外,它与其余的酶均显著或极显著正相关;硅酸盐细菌与所有的酶均极显著正相关。 相似文献
6.
我国土壤退化发生广、发展快,后果严重,很多问题亟待解决,加大其研究力度势在必行。显而易见,人们对土壤特性与土壤退化过程了解得越详细,对土壤退化的评估与防治也会越好。因此迫切需要建立大量土壤退化时间序列来明确土壤退化过程中时间因素的作用并帮助人们正确理解和认识土壤退化与人为作用之间的关系。为了得到可靠的结果,土壤退化时间序列的建立需包括起始土壤相似性判定与退化土壤绝对或相对年龄的验证两个重要过程。本文详细论述了土壤退化时间序列的构建过程及应注意的问题,并探讨了土壤时间序列在我国土壤退化研究中的意义,旨在为土壤退化时间序列的正确建立与应用提供较为详尽的参考。 相似文献
7.
分形理论在土壤肥力研究中的应用与前景 总被引：3，自引：2，他引：1
分形理论的提出对于定量描述复杂的、高度不规则的系统特征与机理提供了方法.本文从土壤腐殖质、土壤微生物、土壤团聚体等方面回顾了分形理论在土壤肥力研究中的主要结果:土壤腐殖质胶体在不同条件下形成不同分形特征的聚合物;同一种微生物可能形成具有不同分形特征的结构;土壤中的有机无机胶体在不同条件下凝聚成不同的团聚体,从而形成不同的土壤结构并对其肥力功能产生影响.我们认为分形理论在探索土壤的形成过程和肥力功能上将具有重要的应用前景:如团粒结构体的形成可能是由土壤胶体分形凝聚而成;土壤中的活性有机质有逐渐老化的现象,可能和腐殖质胶体由结构疏松的分形结构向普通团聚体过渡的过程有关;土壤微生物在不同微环境下具有不同的分形特征,可以推测在各种土壤过程(包括物理、化学以及生物化学过程)中它们的功能也可能是不一样的.此外,土壤结构的开放程度决定孔隙、水分以及空气的分布,从而决定了微生物的生存空间.所以土壤结构体对微生物空间分布的影响也是将来该领域值得研究的内容之一. 相似文献
8.
湖南省典型农田土壤养分现状及近30年变化趋势 总被引：3，自引：0，他引：3
通过文献资料分析及实地调查和采样,对比研究了湖南省典型农田土壤的肥力状况及近30年变化趋势.结果表明:湖南省典型农田当前0 ～ 20 cm 和20 ～ 100 cm土壤有机质平均含量为30.43 g/kg和11.91g/kg,全氮平均含量为1.79 g/kg和0.82 g/kg,全磷平均含量为0.56 g/kg和0.44 g/kg,全钾平均含量为17.13 g/kg和17.17 g/kg.与第二次土壤普查结果比较:除20 ～ 100 cm土壤层次有机质和碱解氮含量呈下降趋势外,其他层次有机质、全氮、全磷、全钾、碱解氮、速效磷、速效钾等土壤养分指标呈显著增加趋势.0～20 cm土壤有酸化趋势. 相似文献
9.
10.
Carbon dioxide emissions after application of tillage systems for a dark red latosol in southern Brazil 总被引：3，自引：0，他引：3
Soil tillage may influence CO2 emissions in agricultural systems. Agricultural soils are managed in several ways in Brazil, ranging from no tillage to intensive land preparation. The objective of this study was to determine the effect of common soil tillage treatments (disk harrow, reversible disk plow, rotary tiller and chisel plow tillage systems) on the intermediate CO2 emissions of a dark red latosol, located in southern Brazil. Different tillage systems produced significant differences in the CO2 emissions, and the results indicate that the chisel plow produced the highest soil carbon loss during the 15 days period after tillage treatments were performed. Emissions to the atmosphere increased as much as 74 g CO2 m−2, at the end of a 2-week period, in the plot where the chisel plow treatment was applied, in comparison to the non-disturbed plot. The results indicate that the total increase on the intermediate term soil CO2 emissions due to tillage treatments in southern Brazil is comparable to that reported for the more humid and cooler regions. 相似文献
11.
Gyrgy Vrallya 《Land Degradation \u0026amp; Development》1989,1(3):171-188
Soil degradation is usually a complex process in which several features of soil deterioration can be recognized. Soil degradation may lead to the loss of land or soil; limitations to normal soil functions; decrease of soil fertility and ‘productive capacity’. The main soil degradation process are: (1) soil erosion by water and wind; (2) Development of extreme soil reaction (acidification; salinization/alkalization); (3) physical degradation (structural destruction; compaction; extreme moisture regime); (4) biological degradation; (5) unfavourable changes in the nutrient regime; (6) decrease of buffering capacity (leading to pollution, toxicity). Soil degradation is not an unavoidable consequence of intensive agriculture and social development. Most of the processes and their unfavourable consequences can be controlled, prevented, eliminated, or at least moderated. A rational strategy of efficient soil degradation control should be based on a system involving the following (consecutive) steps: (a) registration of facts and consequences; (b) analysis of reasons, processes, influencing factors and their mechanisms; (c) determination of the theoretical, real, rational and economic possibilities for control; (d) prediction of the potential impacts of these control alternatives; (e) elaboration and extension of technologies for the optimum alternatives. The present status of soil degradation processes in Hungary is briefly summarized in this paper and the possibilities for control are reviewed, with special regard to soil erosion, salinization/alkalization, acidification and physical degradation (compaction, structure destruction). Based on detailed and comprehensive information on soils (thematic maps of various scales; computerized geographical soil information system) the potential future development of various soil degradation processes is forecast and technologies are elaborated and recommended for use in Hungarian agriculture to prevent soil degradation. 相似文献
12.
Soil organic carbon (SOC), microbial biomass carbon (MBC), their ratio (MBC/SOC) which is also known as microbial quotient, soil respiration, dehydrogenase and phosphatase activities were evaluated in a long-term (31 years) field experiment involving fertility treatments (manure and inorganic fertilizers) and a maize (Zea mays L.)-wheat (Triticum aestivum L.)-cowpea (Vigna unguiculata L.) rotation at the Indian Agricultural Research Institute near New Delhi, India. Applying farmyard manure (FYM) plus NPK fertilizer significantly increased SOC (4.5-7.5 g kg−1), microbial biomass (124-291 mg kg−1) and microbial quotient from 2.88 to 3.87. Soil respiration, dehydrogenase and phosphatase activities were also increased by FYM applications. The MBC response to FYM+100% NPK compared to 100% NPK (193 vs. 291 mg kg−1) was much greater than that for soil respiration (6.24 vs. 6.93 μl O2 g−1 h−1) indicating a considerable portion of MBC in FYM plots was inactive. Dehydrogenase activity increased slightly as NPK rates were increased from 50% to 100%, but excessive fertilization (150% NPK) decreased it. Acid phosphatase activity (31.1 vs. 51.8 μg PNP g−1 h−1) was much lower than alkali phosphatase activity (289 vs. 366 μg PNP g−1 h−1) in all treatments. Phosphatase activity was influenced more by season or crop (e.g. tilling wheat residue) than fertilizer treatment, although both MBC and phosphatase activity were increased with optimum or balanced fertilization. SOC, MBC, soil respiration and acid phosphatase activity in control (no NPK, no manure) treatment was lower than uncultivated reference soil, and soil respiration was limiting at N alone or NP alone treatments. 相似文献
13.
Knowledge on anisotropy of saturated hydraulic conductivity can improve the understanding of transport phenomena in soil. We hypothesized that saturated hydraulic conductivity (Ks) in the upper part of the root zone of an agricultural sandy loam soil was anisotropic at different soil depths and times after tillage. Ks was measured on undisturbed 100 cm3 core samples taken in the horizontal and vertical directions in up to four soil layers (Surf: surface layer (0–5 cm); Top: topsoil (10–15 cm); Trans: transition layer between topsoil and subsoil; Sub: subsoil (40–60 cm)) 1, 8 and 32 months, respectively, after mouldboard ploughing and drilling. The ratio between estimated geometric mean values for Ks in the vertical and the horizontal directions (Kms,v/Kms,h) was used to test the hypotheses. A total of 669 soil samples were analysed.Kms,v/Kms,h varied with time after tillage and between soil layers. One month after ploughing, Kms,v/Kms,h was <0.23 (P = 0.975) in the Trans layer with an average value of 0.084, i.e. Kms,h was 12 times larger than Kms,v. Anisotropy could not be documented in this layer 8 or 32 months after ploughing, i.e. Kms,v/Kms,h was not significantly different from 1.0. For the Surf and Top layers 32 months after ploughing, Kms,v/Kms,h was in the intervals 1.4–50 and 3.1–77, respectively, (P = 0.95) with average values of 8.4 and 15, respectively. Thus, Kms,v was 8.4 respectively 15 times larger than Kms,h in the two layers. Anisotropy was not found in these layers 1 or 8 months after tillage. Strong anisotropy was found in the Sub layer with Kms,v/Kms,h averaging to 14 and 32, respectively, 8 and 32 months after tillage. Kms,v and Kms,h generally decreased with time in the Surf, Top and Trans layers, except in the vertical direction in the Top layer between 8 and 32 months after ploughing, and in the Trans layer between 1 and 8 months after ploughing. Overall, the geometric means of Ks varied between 10−4.0 and 10−7.1 m s−1.The results may reflect systematic effects of soil settlement and drying/wetting phenomena coupled with biological activity and the existence of stable, vertically oriented biopores in the subsoil. It appears to be necessary to consider anisotropy of Ks and its variation in the analysis and modelling of water flow and chemical transport in agricultural soils, particularly to explain heterogeneous flow phenomena at the plot and field scales. 相似文献
14.
J. Paz-Ferreiro C. Trasar-Cepeda M. C. Leirós S. Seoane F. Gil-Sotres 《Biology and Fertility of Soils》2009,45(7):711-722
Although soil biochemical properties are considered to be good indicators of changes in soil quality, few studies have been made of the changes in biochemical properties brought about by anthropogenic disturbance of grassland ecosystems. In the present study, several biochemical properties were analysed in 31 grassland soils subjected to a high level of management, and the values obtained were compared with known values corresponding to native grasslands from the same region (Galicia, NW Spain). The 31 managed grasslands were divided into two groups (re-sown grasslands and improved grasslands) according to their management and past land use. The biochemical properties studied were: labile carbon, microbial biomass carbon, microbial respiration, metabolic quotient, net nitrogen mineralisation and the activities of dehydrogenase, catalase, phosphodiesterase, phosphomonoesterase, casein hydrolysing proteases, benzoyl arginamide (BAA)-hydrolysing proteases, urease, cellulase, ß-glucosidase, invertase and arylsulphatase. Managed grasslands exhibited lower values of soil biochemical properties than native grasslands. Three biochemical equilibrium equations were used to compare soil quality in managed and native grasslands. One of the equations did not show any significant difference between the groups of grassland soils considered. In contrast, two of the equations showed similar soil quality for improved and native grasslands, while re-sown grasslands exhibited a loss of soil quality when compared to native grassland soils. 相似文献
15.
关于耕地土壤污染调查与评价的若干问题探讨 总被引：10，自引：1，他引：10
土壤污染调查与评价是土壤环境研究和管理的重要内容,一直受到各国政府及相关部门的关注。尽管如此,至今有关土壤污染调查与评价的基本认识还相当欠缺。本文基于近20年来作者对相关方面的研究体会与思考,分别从耕地土壤污染调查的全面性、污染评价指标、污染超标率以及土壤环境质量等级划分等几个问题加以探讨,以期为今后更好地开展我国耕地土壤污染调查与评价工作提供参考。 相似文献
16.
Adaptation of soil quality indices and application to three tillage systems in southern Illinois 总被引：2，自引：0，他引：2
Sustainability of agricultural management systems has become an issue of wide public concern and international debate. One result is that soil quality assessment has been suggested as a tool for evaluating sustainability of soil and crop management practices. Our objective was to adapt a soil quality index to assess the effects of three long-term tillage systems on sloping Grantsburg silt loam soil. Soil quality was evaluated using a framework that included three soil functions: (1) resist erosion (water relations), (2) provide plant nutrients (nutrient relations), and (3) provide a favorable root environment (rooting relations). A score for each of these functions was computed using measurements (indicators) that were normalized with one of the three (more is better, optimum, or worse) scoring functions. Six different indices were developed from a basic framework. Modifications included changing the weighting factors, threshold limits, or type of scoring function applied to indicators, and the addition of air-filled and water storage porosity to the nutrient and rooting relations functions. Changing threshold limits and the type of scoring function used for surface residue improved the correlation between water relations and soil loss. The addition of porosity indicators increased the sensitivity of nutrient and rooting relations functions to yield and cone index, respectively, and resulted in a better correlation between porosity indicators and plant population. Computing soil quality indices helped to combine different soil properties and processes into a simple tool that explained changes in complex soil properties in response to different tillage practices. This supports previous studies suggesting that computing soil quality indices and functions could be useful for selecting management practices to maintain or improve soil quality. Our results demonstrated that adjusting threshold limits for local conditions can make the function ratings more or less sensitive to the management practices being evaluated. 相似文献
17.
18.
用土壤温度估算表层土壤导温率与热通量的研究 总被引：10，自引：0，他引：10
对比研究了6种用土壤湿度计算表层土壤导温率的方法结果表明，振幅法、相位法、反正切法、对数法虽需较少观测值，计算简单，但结果却不太稳定；谐波法计算过程虽较复杂，但导温度的估算值较稳定，是最可靠的方法之一。利用计算的土壤导温率估算近地表土壤热通量，结果与由温度积分法决定的土壤热通量值非常一致。 相似文献
19.
Changes in some physical properties of a clay soil in Central Italy following the passage of rubber tracked and wheeled tractors of medium power 总被引：1，自引：0，他引：1
M. Pagliai A. Marsili P. Servadio N. Vignozzi S. Pellegrini 《Soil & Tillage Research》2003,73(1-2):119-129
The aim of this study was to evaluate the compacting effect of rubber tracked tractors in comparison to that of the traditional wheeled tractors. Macroporosity, pore shape and size distribution, bulk density, penetration resistance and saturated hydraulic conductivity were analysed in a clay soil (Vertic Cambisol) near Rome (Italy) following one and four passes on the same track of rubber tracked and wheeled tractors of medium power. The soil structure attributes were evaluated by characterising porosity by means of image analysis of soil thin sections prepared from undisturbed samples. Macroporosity decreased in the 0–10 cm layer of compacted soil, particularly after four tractor passes, due to a large reduction in the proportion of elongated pores and in their vertical continuity. The rubber tracked tractor had a more pronounced compaction effect in the surface layer (0–10 cm) than the wheeled tractor both after one and four passes; the latter treatment producing the lowest soil porosity. The same trend was observed for hydraulic conductivity, which showed a highly significant correlation with elongated pores. In the 10–20 cm layer the porosity was significantly decreased following traffic, apart from in the soil under one pass of the rubber tracked tractor. Again in this layer, the lowest values of porosity were found in soil after four passes of the rubber tracked tractor. Single and multiple passes made by the two tractors induced different effects regarding soil penetration resistance and bulk density. Increment ratio of penetration resistance after tractor passes with respect to the control was: 12.5 and 49.9% with the wheeled and 34.4 and 39.8% with the tracked after one and four passes, respectively. Increment ratio of dry bulk density values after tractor passes with respect to the control was 7.9 and 11.7% with the wheeled and 7.5 and 8.3% with the tracked after one and four passes, respectively. The tractor passes transformed the initial subangular blocky structure into a massive structure with sometimes a platy structure in the upper few centimetres. The results indicated that soil compaction following traffic with the rubber tracked tractor was generally the more pronounced. However the compacting effect of this tractor after one pass seemed to be limited to the surface layer only. 相似文献
20.
Renato Levi-Minzi Alessandro Saviozzi Roberto Cardelli Riccardo Riffaldi 《Archives of Agronomy and Soil Science》2013,59(3):279-288
Fourteen agricultural soils from various areas of Tuscany were characterized by a range of measurements indicative of soil biological activity. The objective of our research was to identify soil parameters suitable as indicators for evaluating their quality. In general, enzyme activities were found to vary widely, with the highest activity for each enzyme being distributed among only five of the 14 soils studied. The narrowest range (14-fold) in enzyme activities for the various soils was observed for catalase and the widest range (577-fold) for g -glucosidase. Biomass C and, among the measured enzyme activities, amylase, were well correlated with total organic carbon, total N, cation and anion exchange capacity. Positive correlations were found between the maximum water holding capacity and dehydrogenase, amylase, biomass C, FDA hydrolytic activity, the biological index of fertility and the enzyme activity number, so showing that soil moisture may play an important role in affecting soil biological characteristics. No significant correlations were observed among the soil enzymes themselves. The FDA hydrolytic activity appeared to be the index most related with the other biological characteristics tested in this study and, for this reason, can be considered the most effective index for putting in evidence relationships existing between the different biological characteristics in the soils investigated. 相似文献