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土壤压实指标在城市土壤评价中的应用与比较 总被引：21，自引：2，他引：19
通过测定南京市不同土地利用下的52个样点的紧实度、容重和孔隙度3个压实指标来反映城市土壤的压实程度。结果表明,南京市大多数土壤存在不同程度的压实,部分压实严重,可能限制植物的生长。不同压实指标在反映土壤压实程度上基本一致,它们之间具有极显著的相关性,可以相互转换。但紧实度指标受到土壤含水量的显著影响。在同一质地或质地相近的土壤,容重和孔隙度可以很好地反映土壤的压实程度。与总孔隙度和毛管孔隙度相比,通气孔隙度在反映土壤压实时更为敏感。所以在进行城市土壤压实状况评价时,可以选择不同的土壤压实程度指标,但就方法的实用性和可靠性来说,容重比紧实度和孔隙度指标一般更方便可靠。 相似文献
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大中小型拖拉机压实对土壤坚实度和大豆产量的影响 总被引：4，自引：3，他引：1
探讨农业机械压实对土壤坚实度和产量的影响规律，对改善作物生产环境、促进农业机械化向质量型转变具有重要意义。以东北典型黑土区耕地土壤为研究对象，依照随机区组试验原理，选择大、中、小3种型号拖拉机进行6种压实处理，同型拖拉机相同压实次数试验重复3次，采用PV6.08型贯穿阻力仪测量压实轮辙截面土壤坚实度。试验结果表明：土壤坚实度随压实次数增加而逐渐递增，3种拖拉机压实测试截面浅层均出现明显压实核，且压实核内土壤坚实度随压实次数增加而逐渐增大，CASE-210型拖拉机压实对表层土壤坚实度影响程度和范围最大，压实12次时压实核处土壤坚实度达4.0 MPa，JD-280型拖拉机对深层土壤压实影响程度和范围最大，在65~80 cm的土壤深层坚实度的峰值达3.2 MPa；拖拉机压实均导致大豆产量降低，CASE-210、JD-904和JD-280拖拉机压实12次时大豆产量分别降低了21.24%、18.15%和12.38%。 相似文献
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城市功能区、植被类型和利用年限对土壤压实的影响 总被引：7，自引：2，他引：5
土地利用会对土壤压实产生影响。本文通过对南京市不同功能区、植被类型和利用年限的土壤进行调查研究,了解这些利用情况对土壤压实的影响程度。结果表明:城郊菜地土壤没有被压实,而城区土壤存在不同程度的压实退化现象;城区内部只有公园土壤与道路绿化带土壤之间的通气孔隙度指标差异显著,其他功能区土壤之间压实指标差异不显著。所以,就压实状况而言,城区内并不存在所谓的功能区之间的差异。植被类型和利用年限对城市土壤的压实都有显著的影响。蔬菜地土壤与自然土壤体积质量和孔隙度相近,为无压实土壤,城区除了树下灌木土壤无压实外,其他植被类型下的土壤均有不同程度的压实退化现象,草坪和裸地土壤压实最为严重。从利用年限看,利用时间少于5年的新土压实程度远远大于利用时间在20年以上老土的压实程度。土壤压实严重与城市建设时的机械压实和草坪建成后的人为践踏密切相关,利用较久的老土壤压实较轻,主要是在无进一步人为践踏情况下,植被生长后根系和土壤生物活动有一定的修复作用。乔木和灌木搭配的修复效果最好。 相似文献
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土壤阻力连续测试设备研制 总被引：2，自引：1，他引：1
为解决目前点采样方法获取的土壤压实信息少和信息获取速度慢的不足,该文研制了可快速连续测量土壤阻力（水平方向）以反映土壤压实程度的测试系统。系统包括机械部分、传感器和信息采集3部分。测试系统由拖拉机牵引,工作时连续测试速度1 m/s,土壤阻力信息采样频率为300 Hz,采样数据处理后与GPS定位数据对应存储。实验室试验表明,系统平均测试精度达93.4%。田间试验显示,测试系统性能可靠稳定,具有连续快速获取土壤压实程度信息并反映土壤压实程度空间分布的能力。定义的土壤阻力指数TRI 可以反映土壤的压实程度。 相似文献
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基于修正介电常数模型的煤矿区复垦土壤压实评价 总被引：1，自引：0，他引：1
模拟复垦机械对试验区土壤进行不同程度的压实,在探地雷达获取土壤介电常数的基础上,检验并修正了4种经典复合介电常数模型,并结合野外试验对修正后的模型通用性进行了验证。结果表明,土壤介电常数与土壤压实指标(土壤紧实度、容重、孔隙率等)相关系数89%,可以表征土壤压实状况;原有复合介电常数模型虽然存在误差不能直接使用,但模型计算值与实测值相关系数0.99,修正后二者拟合误差1%;在野外试验中,基于修正后的介电常数模型反算的土壤压实指标(容重、孔隙率)与实验室测量值误差率5%,通用性较好。表明在科学布设测线以保证探地雷达准确获取土壤介电常数的前提下,可以通过修正后的复合介电常数模型对煤矿区复垦土壤压实状况进行全面客观的评价。 相似文献
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前期含水量对机械压实土壤结构特征的影响 总被引：5，自引：0，他引：5
使用美国MT865履带式拖拉机对东北典型黑土区耕地土壤进行1,3,8,13次的积累压实试验,通过对土壤硬度、广义土壤结构指数的测定及计算·并结合土壤三相的二维三系图对比分析了不同前期含水量条件下土壤机械压实特征.结果表明:由于表层0-10 cm含水量的不同.相对高含水量的土壤剖面受机械压实的影响范围 较低含水量时深10 cm,且各个层次的土壤硬度增量的变化趋势也相对低含水量时滞后10 cm,从初次碾压开始就体现了积累压实作用,在其压实影响范围内硬度与对照相比提高了22.58%～753.85%;而低含水量的土壤则具有相对较强的抗机械压实的能力,同时发现,在土壤承受能力范围内,适当的压实可以有效调节土壤三相,改善土壤结构;秸秆还田不仅具有传统的蓄水保墒、培肥改土的效用,还可以缓解作业机械对土壤的压实. 相似文献
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黄淮海旱作区土壤压实度空间分布特征及其影响因素 总被引：2，自引：2，他引：0
为探究旱作区农田不同层次土壤压实度特征,基于2017年采集的255个土壤样品,运用Mann-Kendall突变检验法、地统计学和冗余分析等方法,探究黄淮海旱作区耕作层和压实层空间分布特征,分析不同层次的土壤压实度的空间变异特性及影响因素,并提出了最佳土壤压实度范围。研究结果表明:旱作区耕作层和压实层厚度均呈现由北向南递增的趋势,耕作层最大厚度可达22.50 cm,最低仅有10.21 cm;压实层厚度最大可达17.50 cm,最小值也达到7.50 cm。从不同层次来看,耕作层和压实层的压实度具有空间分布一致性,耕作层压实度高值区主要分布在河南省东部、安徽北部及河北北部地区,最大值可达87.68%以上,低值区则主要集中在山东西北部以及河北南部地区。和压实层压实度相比,耕作层压实度是影响粮食产量的主要因素,且在70%～80%时获得较高产量。分析表明,土壤压实度受到年降水量、平均气温、土壤自然属性等环境因子和机械耕作等人为因素综合作用的影响。研究结果可为黄淮海农田土壤压实情况的改善及管理措施的科学制定提供理论支撑。 相似文献
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机械压实过程中复垦土壤紧实度影响因素的模拟分析 总被引：13，自引：7，他引：6
机械碾压造成的土壤压实是土地复垦中面临的主要问题之一,影响土壤压实程度的因素很多,除土壤自身的因素以外,还包括压实机械、压实次数以及土层厚度等。该文基于统计学的理论,采用2×5×4的混合试验设计并建立模拟实验区,使用重锤模拟分析了2种压实机械、不同压实次数(1、3、5、7、9次)和不同土层厚度(0~10cm、10~20cm、20~30cm、30~40 cm)上土壤紧实度的变化情况,并在SPSS中进行变量的方差分析和多重比较,试图找到机械压实过程中影响土壤紧实度的因素及其变化水平。结果表明:增加压实机械的承重轮面积能够有效降低对土壤的压实作用;压实机械、土层厚度和压实次数都是影响土壤紧实度的显著性因素且各因素的贡献率(97%)远高于随机误差;自卸汽车在第5次压实之后就已经使上层土壤紧实度达到最大值,而履带式推土机需要压实7次,土地复垦中应尽量选择履带型机械,碾压次数控制在5~7之内;机械压实的过程中,各土层厚度之间土壤紧实度的大小关系并不是一成不变的,中间层次(10~30 cm)的土壤由于同时受到来自上下2个方向的作用力,紧实度相对较高;不同次数的压实对土壤紧实度的影响深度和程度不同,在一定范围内,随着压实次数的增加,单次压实对土壤紧实度的影响逐渐减小。 相似文献
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Vesna Zupanc Gerhard Kammerer Helena Gr
man Igor &#x;antavec Rozalija Cveji&#x; Marina Pintar 《Land Degradation \u0026amp; Development》2016,27(2):406-415
Hydropower plants on the lower river Sava, Slovenia, were developed without sealing the underground upstream. As a consequence, without the countermeasures of elevating and recultivating, the agricultural land on the river banks would be inundated because of the water‐table increase of the river. To remedy this, the fields were elevated and recultivated. The goal of this study was to assess soil quality and production potential after land raising and recultivation and to answer the question whether it is possible to recover soil quality and crop yield after large‐scale mass manipulation, such as land raising. After recultivation and after the second year of land reuse for the two cultures grass–clover mixture and corn on two sites, Middle Pijavsko and Lower Pijavsko, soil physical and chemical characteristics and crop yields were evaluated. Mixing of topsoil with the second horizon during removal and during backfill with filling material resulted in uneven soil fertility, plant growth and decreased yield. Driving on the refilled second layer with heavy machinery caused soil compaction in the Middle Pijavsko in spite of favourable soil texture (loam, 38·7% sand). On the areas with very high sand content (over 55%) and low clay content (10%), soil compaction was not as severe or persistent. Recultivation measures restored the agricultural land almost to the production potential prior to powerplant construction. Immediate intensive land use (corn) showed less favourable effect on soil characteristics. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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滇东南石漠化山地不同植被恢复模式下土壤地力变化和水土流失状况研究 总被引：2，自引：1，他引：1
通过对滇东南石漠化山地不同植被恢复模式下土壤的理化性质进行定点观测和地力变化及水土流失状况的分析,结果表明:封山育林地土壤的肥力较佳,其次是耕地土壤,这是由于封山育林地土壤多年来进行封山育林,耕地土壤进行了平衡施肥;3年后人工林地土壤的理化性质有很大改善,土壤肥力有很大提高,这是退耕还林的结果;从水土流失状况来看,耕地是产流产沙、固体和液体养分流失最严重的类型,人工林地水土流失最低,说明退耕还林和封山育林有利于石漠化山地土壤肥力的改善和水土保持功能的提高。 相似文献
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Protecting soil structure against compaction—proposed solutions to safeguard agricultural soils To safeguard the ecological soil functions and the functions linked to human activities, measures against harmful changes to the soil are required, in line with the precautionary principle. The German Federal Soil Protection Act sets obligations for precaution in agricultural land use and, if harmful changes to the soil are foreseeable, measures for averting a danger. The results of a research project of the Federal Environmental Agency show that it is possible to describe an impairment of the soil structure, using methods of soil analysis. But this as a sole information would not qualify for the identification of harmful changes to the soil in the context of the Soil Protection Act, which requires an assessment of the severity of disruption of soil functions and the respective subject of protection. This would make additional soil investigations on site mandatory. Approaches in agricultural engineering and soil physics have introduced procedures to preserve the soil structure, in accordance with the precautionary principle. But these procedures have different goals and different ranges of application and hence offer partial solutions to safeguard against soil compaction. The assessment model of “trafficability by measuring the rut depth” provides information about the compaction status of the soil under applied conditions for farming gear, without providing detailed information about affected soil layers. The soil‐physical model of classifying soils into “risk classes for harmful soil compaction” focuses on the relationship between topsoil compaction and crop yields. The soil‐physical models “precompression stress” and “loading ratio” provide information for the assessment of subsoil compaction and a prognosis of a possible impairment of the soil structure at the water content of field capacity. It is necessary to validate the individual models with additional regional data about soil structure before a final assessment of the prognoses is made. 相似文献
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Infiltration capacity is an important variable for understanding and predicting a range of soil processes. This study investigated for different slope positions the effects of forest conversion to cultivation and grazing on soil infiltration capacity. Infiltration capacity was measured in the field in each land use type using a double‐ring infiltrometer. A total of 108 soil samples (3 slope positions × 3 land use types × 4 soil profiles × 3 soil depths) were collected to determine the variables that affect infiltration capacity viz. particle size distribution, organic carbon content, dry bulk density and soil moisture content. The results showed that in the cultivated and grazed land compared with forest, infiltration capacity and soil moisture content were 70 and 45% smaller respectively, and dry bulk density was 13–20% larger. Changes in soil structure caused by surface soil compaction because of tillage and animal trampling coupled with a smaller soil organic carbon content, are likely to be the principal factors causing the decline in infiltration capacity and soil moisture content after conversion of forest to cultivation and grazing. 相似文献
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The influence of different types of urban land use on soil microbial biomass and functional diversity in Beijing,China 总被引：1，自引：0，他引：1
Soil microbes in urban ecosystems are affected by a variety of abiotic and biotic factors resulting from changes in land use. However, the influence of different types of land use on soil microbial properties and soil quality in urban areas remains largely unknown. Here, by comparing five types of land use: natural forest, park, agriculture, street green and roadside trees, we examined the effects of different land uses on soil microbial biomass and microbial functional diversity in Beijing, China. We found that soil properties varied with land uses in urban environments. Compared to natural forest, soil nutrients under the other four types of urban land use were markedly depleted, and accumulation of Cu, Zn, Pb and Cd was apparent. Importantly, under these four types of land use, there was less microbial biomass, but it had greater functional diversity, particularly in the roadside‐tree soils. Furthermore, there were significant correlations between the microbial characteristics and physicochemical properties, such as organic matter, total nitrogen and total phosphorus (P < 0.05), suggesting that lack of nutrients was the major reason for the decrease in microbial biomass. In addition, the larger C/N ratio, Ni concentration and pool of organic matter together with a higher pH contributed to the increase in microbial functional diversity in urban soils. We concluded that different land uses have indirect effects on soil microbial biomass and microbial community functional diversity through their influence on soil physicochemical properties, especially nutrient availability and heavy metal content. 相似文献
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T. Batey 《Soil Use and Management》2009,25(4):335-345
Soil compaction is an important component of the land degradation syndrome which is an issue for soil management throughout the world. It is a long standing phenomenon not only associated with agriculture but also with forest harvesting, amenity land use, pipeline installation, land restoration and wildlife trampling. This review concentrates on the impact of soil compaction on practical soil management issues, an area not previously reviewed. It discusses in the context of the current situation, the causes, identification, effects and alleviation of compaction. The principal causes are when compressive forces derived from wheels, tillage machinery and from the trampling of animals, act on compressible soil. Compact soils can also be found under natural conditions without human or animal involvement. Compaction alters many soil properties and adverse effects are mostly linked to a reduction in permeability to air, water and roots. Many methods can be used to measure the changes. In practical situations, the use of visual and tactile methods directly in the field is recommended. The worst problems tend to occur when root crops and vegetables are harvested from soils at or wetter than field capacity. As discussed by a farmer, the effects on crop uniformity and quality (as well as a reduction in yield) can be marked. By contrast, rendzinas and other calcareous soils growing mainly cereals are comparatively free of compaction problems. The effect of a given level of compaction is related to both weather and climate; where soil moisture deficits are large, a restriction in root depth may have severe effects but the same level of compaction may have a negligible effect where moisture deficits are small. Topsoil compaction in sloping landscapes enhances runoff and may induce erosion particularly along wheeltracks, with consequent off‐farm environmental impacts. Indirect effects of compaction include denitrification which is likely to lead to nitrogen deficiency in crops. The effects of heavy tractors and harvesters can to some extent be compensated for by a reduction in tyre pressures although there is concern that deep‐seated compaction may occur. Techniques for loosening compaction up to depths of 45 cm are well established but to correct deeper problems presents difficulties. Several authors recommend that monitoring of soil physical conditions, including compaction, should be part of routine soil management. 相似文献
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坡耕地严重的水土流失是导致黄土高原土壤质量退化与生态环境恶化的重要原因。采用模拟降雨的方法研究了翻耕与压实对休闲黄绵土坡耕地水分转化与产流产沙特征的影响。结果表明，(1)与压实相比，土壤翻耕导致入渗率下降40%～60%，产流强度增加1至3倍，降雨向土壤水分的转化率降低50％以上。(2)翻耕条件下流失径流的平均含沙量增加近70％，坡地产沙量增加3倍，径流流失量增加1倍，因此对坡地实行免耕休闲可以有效减轻水土流失、遏制坡地土壤质量退化的态势。(3)降雨过程中，随着产流时间的延长，坡地产沙量呈加速增加的趋势，而且增加速度显著快于坡面径流，因此采取适当措施延长初始产流时间、减少产流量以及提高降雨向土壤水分的转化率均可有效减少坡地土壤流失量。 相似文献
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Structural disruption of arable soils under laboratory conditions causes minor respiration increases 
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下载免费PDF全文 Previous field studies in N Europe have shown that the impact of soil tillage on soil respiration is mostly indirect, caused by altered distribution of plant residues in soil affecting decomposition of residues. Tillage operations alter soil moisture and temperature conditions in soil, which control decomposition dynamics. Experiments under laboratory conditions allow indirect effects of altered residue decomposition to be distinguished from direct effects of mechanical disruption, i.e., the increased exposure of substrates within aggregates and micropores upon tillage. This study examined the effects of physical disruption of soils with different soil texture, land‐use history, and soil organic C content on soil respiration under controlled abiotic conditions. Undisturbed soil samples from 7 sites (arable land and grassland) were incubated at 20°C and three different water potentials (–1, –10, and –30 kPa). Soil respiration was measured before and after physical disruption with laboratory homogenizer, using an automated respiration apparatus. Soil organic C, water content, and bulk density explained 67% of the variation in base respiration. In half of the disrupted samples, bulk density was re‐adjusted by re‐compaction to conditions prevailing before disruption. Disruption and re‐compaction generally resulted in higher respiration flushes than disruption alone. Respiration peaks increased with water content. However, total C losses were small and corresponded to < 0.1 Mg C ha?1. Overall, physical soil disruption increased decomposition of soil organic matter only marginally and temporarily. It would be difficult to detect an effect of tillage on soil organic matter decomposition under field conditions. 相似文献
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两种利用类型煤矸山复垦重构土壤贮水特性研究 总被引：6，自引：0，他引：6
土壤贮水能力是复垦地植被恢复和生态重建的基础。因此开展煤矸山复垦重构土壤贮水能力研究对于指导煤矸山植被复垦具有重要意义。以长治王庄煤矸山复垦6 a的林地（SL）和草地（GL）为对象,分析了2种利用类型煤矸山复垦重构土壤1 m土层贮水状况。结果表明:（1）复垦林地（SL）和复垦草地（GL）土壤容重分别较普通林草地（CK）高12.7%和19.0%（p > 0.01）。两种复垦地土壤容重的剖面变化有别于普通农地,并且其差异主要体现在60 cm以上土层。（2）SL样地和GL样地土壤总孔隙度分别较CK样地低20.5%和30.9%,非毛管孔隙度分别较CK低80.0%和74.9%,而土壤毛管孔隙度分别较CK样地高14.1%和2.4%,因此,两种复垦地土壤饱和贮水量和非毛管贮水量明显低于普通农地,但毛管贮水量高于普通农地。（3）SL样地和GL样地1 m土层土壤平均含水量和总贮水量分别较CK样地高7.8%,12.3%和23.5%,34.9%,但两种复垦地与普通农地1 m土层含水量和贮水量的差异在60—100 cm最大。 相似文献