不同干扰对城市绿化用地土壤物理性质的影响

为了解压实对城市新建绿地土壤物理性质的影响,以西安植物园新园区为研究对象,依据土壤压实程度的不同以及地表植被的差异进行区域划分,对不同区域内的土壤分层采样,并进行土壤容重、孔隙状况、水分常数等物理性质的测定。结果表明：随着压实程度的增加,土壤各层次间的发生规律发生了改变,土壤出现退化现象。研究区域内的土壤容重偏高,平均值为1.52 g/cm³;土壤总孔隙度、通气孔隙度、土壤含水量、田间持水量、土壤饱和导水率明显偏低,平均值分别为44.71%、12.81%、15.46%、20.77%、20.7 mm/h。土壤容重与总孔隙度、通气孔隙度、田间持水量、自然含水量、饱和导水率之间呈极显著的负相关;通气孔隙度与饱和导水率、自然含水量、田间持水量之间均呈现显著的正相关。压实对各层土壤物理性质的影响表现为表层土>浅层土>深层土,人为践踏产生的压实只影响到表层土壤。     

Auswirkungen differenzierter Bodenbearbeitung auf das Bodengefüge und die Stickstoffdynamik von Lößböden bei viehloser und viehstarker Bewirtschaftung

Effect of different tillage practices on soil structure and nitrogen dynamic in loess soils with and without longterm application of farmyard manure
Field trials were conducted in 1979 and 1980 on two farms with and without longterm application of farmyard manure respectively, to study the effect of different tillage practices (ploughing at low soil moisture in summer and autumn and ploughing at highsoil moisture in autumn) on soil structure and nitrogen dynamic. Soil structure measurements showed great differences between ploughing at low and high soil moisture contents. Ploughing soil at high moisture contents caused a rise in penetrometer resistance as in bulk density and a decrease of macropors as well as in oxygen concentration in top soil and in tillage pan. But little differences were observed between ploughing in summer and autumn at low soil moisture contents.
Ploughing soil at high moisture contents caused a higher soil compaction on the farm without longterm application of farmyard manure compared to the farm with longterm application of farmyard manure.
The differences in soil nitrate content were strongly correlated with soil compaction. Very large differences in soil nitrate content between ploughing at low and high soil moisture contents were always observed in May, when the soil temperature was higher than 15°C These differences in soil nitrate content are due to reduced nitrogen mineralization and an increase of denitrification activity after ploughing at high soil moisture contents.     

相同储藏条件下同年度不同品种小麦品质的变化

选用5个同一生产年度的不同品种小麦,在同一储藏条件下对其容重、水分、面筋吸水量、粘度、降落数值和发芽率等品质指标进行测定,讨论各指标与储藏时间的关系及品种差异对各指标的影响,分析各指标之间的相关性。结果显示:随着储藏时间的延长,小麦容重、水分和粘度的变化趋于稳定,面筋吸水率和发芽率呈降低趋势,降落数值呈增大趋势;不同小麦品种的容重、发芽率变化差异不大;储藏1年后,不同小麦品种的水分、面筋吸水率、降落数值变化差异较大;容重与其它五个指标都存在一定的相关性,这也是选择容重作为小麦等级鉴定的必要性。     

土壤机械压实与甜菜生长研究进展

土壤机械压实是由于机械化作业引起的土壤结构破坏,导致土壤质量下降,已经成为制约农业可持续发展障碍因子之一。笔者阐述了国内外有关土壤机械压实对土壤容重、坚实度、孔隙度、地表水分渗透、土壤含水率等特性的影响,分析了土壤压实后引起的农业机械机组作业阻力增加、油耗上升,以及对甜菜生长的不利影响,造成甜菜产质量下降。提出了在大力发展甜菜生产机械化发展的同时,应切实考虑其负面影响,采取固定到作业、联合作业等技术措施,改善土壤压实情况,确保甜菜可持续生产。     

Drainage and tillage effects on a crosby-kokomo soil association in Ohio IV. Soil physical properties

Bulk density, soil structure, penetrometer resistance, and moisture retention characteristics were examined for the Crosby-Kokomo Association near Columbus, Ohio. The soils are classified as fine mixed, mesic, Aeric Ochraqualf and fine, mixed, mesic, Typic Argiaquoll, respectively. Effects of four tillage methods were studied with and without subsurface drainage. Tillage methods were: no-till, raised beds, ridge till and moldboard plow. The tillage treatments were laid out according to a Randomized Block Design with three replicates on each drainage site.Soil samples obtained in August, 1987 to 50 cm depth in 10 cm increments, were analyzed for aggregate size distribution, and moisture retention characteristics. In addition, surface (0–10 cm and 10–20 cm depths) core samples were obtained in July 1989 for measurement of soil bulk density, and moisture retention characteristics. Penetrometer resistance and soil moisture content for the surface layers were also measured in July 1989.The mean weight diameter (MWD) was higher for undrained than drained treatment, 2.94 mm vs. 2.49 mm, respectively. Neither drainage nor tillage treatments had a significant effect on soil bulk density measured about 8 weeks after sowing. Penetrometer resistance was lower, and surface soil moisture content was higher in the undrained compared with the drained treatment. Soil moisture retention at all suctions and plant-available soil moisture reserves were more in undrained than drained soil. Differences in soil moisture retention among drainage treatments are attributed more to organic matter induced differences in pore size distribution than to total porosity. For these soils in central Ohio, drainage had a more significant effect on soil physical properties than tillage operations performed in the fall and/or spring.     

Effect of Ten Successive Rollings on Soil Physical Properties and Yield of Groundnut (var. TMV 3) in a Very Permeable Sandy Soil in Southern India

Trial in a farmer's holding, which was sandy containing 80-90 per cent of fine and coarse sand fraction, was conducted to evaluate the effect of ten successive rollings by 400 kg stone roller (1 meter width) on the soil physical properties and yield of groundnut (var. TMV 3). By rolling, the bulk density was increased from 1.50 g/cc to 1.63 g/cc in the 20-30 cm layer; Hydraulic conductivity was reduced from 36.7 cm/h to 17.3 cm/ h in the same subsoil layer (53 per cent over control) which resulted in higher moisture retension capacity of the soil, the increase being 51.5 per cent over control in the 30-40 cm layer. The final dry pod yield increase was 19 per cent over control. The effect of compaction was seen at the post-harvest soils also, in that the increase in bulk density, decrease in hydraulic conductivity were observed. The variations were more effective at 10-20 cm laver.     

小麦水分含量对容重及硬度的影响

容重是国内外粮食定等及评价粮食工艺品质的主要指标,小麦籽粒硬度是国内外小麦市场分类和定价的重要依据之一,通过改变小麦水分含量,判定其对小麦容重及硬度的影响。结果表明,在一定的水分范围之内,小麦容重与水分含量呈负相关,小麦籽粒硬度与水分含量呈正相关。     

Transport of Anion Towards Root as Influenced by Soil Compaction

This experiment was conducted in metal container of 2 liters capacity in the glass house to find out the effect of different bulk densities on the movement of non-adsorbed anion (Cl) towards the root. It is inferred from the study that at low moisture content, compaction to a certain degree can increase movement of nutrients to the root due to increase in moisture content per unit volume of soil, further increase in compaction may however affect nutrient availability to the roots. This has a far greater significance in No₃ movement. But from the salinity point of view, plant roots in soil containing salt will be exposed to a much higher salt concentration than that may be obtained from the analysis of the bulk soil.     

机械碾压对新建城市绿地土壤理化性质的影响

为了揭示机械碾压对城市绿地土壤的影响,为城市植被栽植及土壤科学管理提供参考,以在建的西安植物园新园区为例,对机械碾压前后园区土壤理化性质和养分特征进行了研究与分析。结果表明：碾压后土壤容重升高,孔隙度普遍降低,0~30、30~60、60~100 cm土壤容重分别高出碾压前4.20%、14.60%、20.70%;碾压后土壤pH升高;碾压后,土壤表层速效氮含量普遍升高,提高了287%,表层土壤速效磷含量提高了20.30%,表层土壤速效钾含量提高了12.10%,碾压前后表层土壤有机质含量变化不大。碾压破坏了土壤结构,导致土壤容重增加,土壤pH升高,改变了土壤养分分布。针对以上问题及植物园建设的复杂性,须采取精准的土壤改良措施并长期监测碾压对植物生长的影响。     

土壤机械压实及其对作物生长的影响

在生产中农业机械替代人畜力从事农业生产劳动是必然的趋势。随着农业机械化水平的快速提高,土壤机械压实问题越来越突出。通过分析土壤机械压应力传递模型,以及土壤压实后土壤容重、坚实度增加,孔隙度、含水量降低,土壤的渗透性变差等土壤质量恶化现象,发现土壤压实可导致土壤质量下降,抑制作物的根系生长发育,对作物吸收土壤中的水分、养分产生不利影响。可造成玉米减产9.5%～14.4%,小麦减产4.0%～20.0%,大豆减产3.8%～13.4%,甜菜根产量降低5.81%～24.13%,含糖率降低0.49～0.81oZ。因此,在农业生产中必须要重视土壤压实问题,采取切实可行的技术措施,减轻农业机械化作业对土壤造成的负面影响,促进作物生长,提高农艺综合效益。     

新疆连作棉田耕层土壤理化指标研究

以新疆长期连作棉田为研究对象,通过田间调查、取样测定的方法,研究新疆连作棉田不同产量水平条件下土壤理化指标变化特征。结果表明：随着棉花产量增加棉田耕层深度、犁底层厚度均呈增加趋势,但不同产量水平差异未达显著水平。土壤紧实度、土壤容重和土壤含盐量则呈下降趋势,其中高产田土壤紧实度在10-46cm显著低于中、低产田,而高产田耕层土壤容重和土壤含盐量显著低于中、低产田,但高产田土壤粘粒较中、低产田有所提高,而一定比例的粘粒有利于提高土壤保水性。高产田耕层土壤有机质、速效氮含量较高,表现为高产田>中产田>低产田,而速效磷、速效钾无显著差异。从产量构成因素来看,单株铃数是影响产量的主要因素,其次是单铃重,衣分无明显变化。     

深翻耕作对连作滴灌棉田土壤含水率及含盐量影响的研究

探讨播前不同翻耕深度对连作滴灌棉田土壤容重、土壤含水率、土壤含盐量的影响。针对典型的连作滴灌棉田,于播前设置20、40和60 cm的3个不同深度翻耕处理,于生育期测定各处理不同土壤剖面的上述内容,研究其变化。（1）土壤容重随翻耕深度增加而下降,其中表层土壤容重降幅大于深层土壤容重;（2）3种深翻处理下土壤剖面含水率均为0~20 cm＞20~40 cm＞40~60 cm,随翻耕深度增加,0~20 cm土壤含水率呈上升趋势,20~40 cm土壤含水率变幅不大,40~60 cm土壤含水率则显著下降;（3）灌水后,深翻20 cm的土壤含盐量为0~20 cm＞20~40 cm＞40~60 cm,但随翻耕深度的增加,0~20 cm土壤含盐量呈下降趋势,20~40 m和40~60 cm的土壤含盐量迅速上升趋势,至深翻60 cm时,土壤含盐量则为40~60 cm＞20~40 cm＞0~20 cm。对连作滴灌棉田播前进行60 cm的超常深翻,可有效降低耕层土壤容重,提高0~20 cm表层土壤含水率,降低含盐量,从而利于作物生长。     

农田机械化耕作与甜菜生长

近年来随着农业机械化水平的快速提高,土壤机械压实问题越来越突出。通过分析土壤机械压实对土壤容重、坚实度、孔隙度、地表水分渗透、土壤含水率等特性的影响,阐述了土壤压实后引起的农业机械机组作业阻力增加、油耗上升,以及对甜菜生长的不利影响,造成甜菜减产。在促进农业机械化发展的同时,应切实考虑其负面影响,采取切实的措施,改善土壤压实情况,确保甜菜可持续生产。     

土壤容重的修订方法研究

为了自动土壤水分观测资料更准确、更好地服务于实际应用以及应用于科学研究,从理论上分析自动土壤水分观测与人工实测值存在误差的原因及修正办法,通过公式 ,用每次计算的土壤容重的平均值代表修正的土壤容重,分析评估用修正的土壤容重计算土壤重量含水率的可行性。结果表明：土壤容重修正公式可靠,利用自动观测土壤水分含水量以及土壤容重修正公式来计算土壤重量含水率可行,理论上可以取消逢八观测,也为自动土壤水分观测资料的实际应用、为两年一度的自动传感器评估提供一种指导方法。     

草原露天矿区重构土壤典型物理性质与生物量的关系

以内蒙古锡林郭勒盟胜利矿区一号露天煤矿为例,将南、北排土场复垦地作为研究对象,以未损毁地作为对照,采用方差分析和Pearson相关性分析的方法,研究复垦地重构土壤典型物理性质（土壤容重、土壤含水率）与植被地上生物量的关系,以期为草原矿区土壤重构与植被重建提供实践支撑。结果表明：（1）复垦地土壤容重与含水率相关性强度略低于未损毁地,复垦时间越长重构土壤容重与含水率的负相关性越显著;（2）复垦地植被生物量的均值都高于未损毁地,复垦后的土壤环境因子促进了排土场生态系统的重建;（3）在0~10 cm土层,土壤容重与含水率呈负相关性,生物量与容重相关性极弱或无相关,但生物量与含水率呈强的显著正相关关系,说明表层土壤含水率是影响植被生物量的重要因子。     

The effect of grass roots on shear strength variations with moisture content

This study investigated the relationship between vane shear strength and moisture content for root-free and root-permeated sandy clay loam and clay soils, with a view to determining the effect of root density on the relationship. The results indicate that for both root-free and root-permeated soils, shear strength increases exponentially with decreasing moisture content. As expected, increases in root density considerably increase the magnitude of shear strength at all moisture contents investigated. In all cases, roots increased the magnitude of the shear strength of the clay soils much more than the sandy clay loam soils. Relative to the root-free soils, the roots increased shear strength in both soils by at least 500%. In the clay soils a higher relative increase of up to 850% is achieved in samples with a root density of 1.80 g cm⁻³. Also, relative to root-free soils, root permeated soils were found to exhibit a higher rate of shear strength increase with soil drying. This, it is suggested, is because of the higher shading effect of the shoots of the root-permeated samples leading to a slower rate of soil drying than in the root-free samples.     

Evaluation of the changes in some soil properties as related to various ameliorative managements

Alternatives for improving the soil water properties of clay surface water logged soils are presented. Investigation were carried out on a strongly leached chernozem using two types of drainage systems: drainage only and drainage with water accumulating. The soil is initially treated by deep loosening and providing mole drainage. This treatment improved the bulk density, porosity and water permeability.After deep loosening down to 70–75 cm, soil compaction on the entire profile changes linearly with the time. By the end of the fourth year only in the uppermost horizon the bulk density of the loosened soil reaches its initial value. During the first few years after the deep loosening the coefficient of filtration in the soil profile remained greater than 0.2–0.3 m/day. These values are acceptable from a practical point of view as regards soil aeration and soil water storage.Mole drainage carried out at 55–65 cm was successful. There was no compaction of the soil profile except for the zone around the mole channel.     

深圳城市绿地土壤孔隙状况与水分特征研究

为了了解深受人为活动强烈影响的城市绿地的土壤物理特性,为充分发挥其增进植物生长、涵养水源和保护城市生态环境等功能提供管理依据,以深圳城市绿地土壤为研究对象,调查分析了土壤容重、孔隙状况、土壤水分常数和水分入渗特征等物理特性。结果表明：深圳城市绿地土壤的容重较高,平均值为1.56 g/cm3。土壤总孔隙度、毛管孔隙度、通气孔隙度较小,平均值分别为41.06%、39.78%、1.27%。土壤水分入渗率变幅很大,土壤初始入渗率为0~8.47 mm/min,稳定入渗率为0~5.90 mm/min。城市公园绿地、道路绿地土壤的容重显著高于城郊菜地土壤,而土壤孔隙度、最大持水量、毛管持水量和田间持水量显著低于城郊菜地土壤;表层0~10 cm的土壤容重、最大持水量、毛管持水量和田间持水量显著低于10~20 cm土壤,土壤孔隙度显著高于10~20 cm土壤。城市绿地土壤容重与孔隙度、田间持水量、最大持水量、初始入渗率及稳定入渗率均呈显著的负相关。     

Genotypic Variation in Root Systems of Chickpea (Cicer arietinum L.) across Environments

Root systems of various chickpea genotypes were studied over time and in diverse environments, – varying in soil bulk density, phosphorus (P) levels and moisture regimes. In a pot study comparing a range of chickpea genotypes, ICC 4958 and ICCV 94916‐4 produced higher root length density (RLD) and root dry weight (RDW), which were better expressed under P stress conditions. In two field experiments in soils of intermediate and high soil bulk densities, ICC 4958 also had greater RLD and RDW, particularly under soil moisture stress conditions. The expression of greater rooting ability of ICC 4958 under a wide range of environmental conditions confirms its suitability as a parent for genetically enhancing drought resistance and P acquisition ability. The superiority of ICC 4958 over other genotypes was for root proliferation expressed through RLD. Thus, the variation in RLD can be the most relevant root trait that reflects chickpea's potential for soil moisture or P acquisition.     

基于模糊数学法的新建绿地土壤物理性能评价

城市绿地土壤的物理性能影响着城市生态系统的运行,为了研究城市绿地建设过程中不同层次土壤的物理性能,以西安植物园新区为典型案例,选取容重、总孔隙度、毛管孔隙度、非毛管孔隙度、田间持水量、自然含水量等六个指标,结合模糊数学法以及SPSS19.0与Excel软件对各层土壤的物理性能(Q)进行评价。结果显示,西安植物园新区表层土壤(0-25cm)、浅层土壤(25-50cm)、中层土壤(50-70 cm)、深层土壤(70-90cm)的Q值分别为21.69、61.24、71.19、66.89;分别处于极差水平、较差水平、良好水平、较差水平。平均Q值为55.25,处于较差水平。表层土壤与浅层土壤Q值过低的原因在于重型机械的重复碾压,碾压力对中层土的影响较小。随着土层深度的增加,深层土壤的Q值相对中层有所下降。各影响因子的权重比较显示,土壤容重是影响各层土壤物理性能优劣的重要因素,但随着土层的加深,土壤容重的权重逐渐降低。自然含水量的权重随着土层的加呈现逐步上升的趋势。