煤矸石层的充填结构对土壤水分入渗规律的影响研究

摘要：为探讨煤矸石的存在对矿区土壤入渗的影响。采用室内一维定水头垂直入渗试验，对含煤矸石层土柱在3种容重条件下（1.2、1.3、1.4 g/cm3），按其在土柱中厚度（4、8、12 cm）和位置（上层、中层、下层）的不同，进行土壤入渗规律研究。结果表明：⑴煤矸石位于土柱上层时，厚度增加进一步提高了土壤入渗；位于中层时均抑制了入渗；位于下层时对入渗的影响较小。⑵土壤入渗随容重的增大而减小。同一煤矸石容重和厚度，其位置影响入渗的排序为：上层＞下层＞中层。⑶本试验所设厚度对土壤入渗影响不显著，而位置和容重影响极显著。通用公式可更好反映土壤入渗规律。     

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。     

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。     

Dynamic Influence of Sustained Small Rainfall Infiltration on Stability of Unsaturated Soil Slope

Taking the moisture content as main control parameter of shear strength of the soil, we analyze the variational properties of moisture content and shear strength with the change of rainfall time during the small sustained rainfall infiltration, and establish the relationships between total cohesion as well as effective angle of friction and the time of sustained small rainfall infiltration into an unsaturated slope. With the rainfall infiltration, the influence area of slope expands. Through the strength reduction method based on FLAC3D, the dynamic safety factor of slope in different time and the duration time before the failure of the slope are obtained. The results show that the slope critical sliding surface is yet unsaturated during a sustained small rainfall.     

西南黄壤坡耕地保护性耕作的土壤结构效应

设置两种保护性耕作措施,通过6a持续试验,研究了保护性耕作措施对黄壤结构性状的影响,为西南黄壤地区保护性耕作技术应用与发展提供理论依据。[方法]分别用环刀法、干湿筛法测定土壤容重和土壤团聚体组成,土壤机械组成采用MS2000激光粒度分析仪测定,并计算出土壤孔隙度和团聚体破坏率。 [结果]结果表明：(1)垄播沟覆轮耕与免耕秸秆覆盖两种保护性耕作措施均可降低黄壤容重,增加土壤孔隙,且此作用是由表及里的渐进过程,垄播沟覆措施的土壤容重优化作用要优于免耕覆盖,而免耕覆盖对较深层次土壤孔隙状况优化效果更显著。(2)保护性耕作可提高0～20 cm土壤＞0.25mm干筛团聚体含量,水稳性团聚体含量处理之间差异不显著,但0～20cm层含量略大于20～40cm层。(3)保护性耕作可提高土壤团聚体稳定性,降低团聚体破坏率,免耕覆盖措施对提高土壤团聚体稳定性具有更加显著的效果。[结论]该试验证明了保护性耕作对黄壤土容重、孔隙、团聚体等结构性状有一定的改善作用,这种改善作用是一个非常漫长的由表及里的渐进过程,为西南黄壤地区保护性耕作技术应用与发展奠定了坚实的基础。     

Effect of Tillage System on Soil Strength and Bulk Density of Vertisols

Improving the soil environment for seedling emergence and plant growth is possible using a good tillage system. From March 1993 until June 1994, the effect of tillage system and plant residue incorporation practices on the bulk density and the soil strength of the surface layer of a vertisol (very fine, smectitic, thermic, chromic Haploxerert), on a less than 1 % slope, was investigated. The two tillage methods were moldboard (T1) and chisel (T2). The two plant residue incorporation dates were in August (R1) and in October (R2). Results indicated that R1 gave significantly higher bulk density than R2, while the different tillage treatments had no significant effect. Soil strength was significantly lower under T1 and R2 than under the other treatments.     

降雨条件下坡积土边坡暂态饱和区形成机理及分布规律

降雨是引起坡积土边坡失稳的最常见外部因素之一。雨水的入渗在引起土体抗剪强度参数降低的同时,还将导致土体重度的增加、基质吸力的降低,最终造成边坡的失稳。开展雨水在边坡内部的渗流过程研究已成为分析边坡在降雨条件下稳定性的前提。基于有限元数值模拟方法,进行了雨水在土体中渗流过程的模拟,着眼于降雨条件下边坡暂态饱和区的形成、分布及消散特征,描述了该过程中边坡内部含水率、基质吸力、水力梯度的变化规律。结果表明：暂态饱和区形成的主要原因是土体中向湿润锋下方渗出的雨水量小于降雨入渗补给量,从而使得土体中的含水率累积升高;暂态饱和区的形成与降雨强度、降雨时间具有十分密切的关系,暂态饱和区形成时间、雨水入渗深度、土体表面体积含水率大小分别与降雨强度存在函数关系;清晰描述了暂态饱和区形成发展消散地下水位升高的全过程,从该过程看,边坡排水措施的设计值得思考。     

土壤容重对高产玉米根系生长的影响及调控研究

不同土壤容重不同,其稳定性也不同。土壤容重的变化会引起土壤调节水、气、热能力的变化,提高土壤的自动调节能力可以使土壤肥力水平得以提高并满足植物对生长因子的持续需求。为研究土壤物理性质对玉米高产稳产的影响机理,以耕地棕壤为试验材料,采用盆栽方法,研究不同容重对玉米根系生长指标的影响,并进一步研究了施用不同有机肥量及模拟不同耕作深度对玉米根系生长的调控效果。结果表明:在设计容重范围内,容重增加,根系生长指标都表现为下降,容重大于1.2 g/m3时,不同处理根系生长指标差异显著;当容重大于1.3 g/cm3时,不同处理根系活力差异显著。施用有机肥对高容重土壤调控效果更好,有机质含量为4%与5%的处理差异减小,低容重土壤在所设计的有机质水平内调控效果也都较好。耕层厚度增加可以提高根系生长参数,但与对照相比,差异不显著。所以,对于紧实结构性较差的土壤,改善其调节能力应该通过增施有机肥的方法,紧实结构较好的土壤考虑使用耕翻的办法。     

放牧对草地土壤含水量与容重及地下生物量的影响

摘要：对滇东北人工草地不同放牧压下土壤含水量、土壤容重和地下生物量的变化进行研究,结果表明：（1）放牧利用对主要影响表层（0-5cm）土壤含水量和土壤容重,表层土壤含水量随着放牧压的增大而减小,土壤容重则以GPI0.76最大,GPI0.57下土壤容重随放牧时间波动较小,说明适度的放牧利用有利于稳定土壤结构;（2）草地植被地下生物量主要分布在0-10cm土层,占0-30cm土层的64-74%,地下生物量随放牧压增加而减少。     

土壤入渗特性影响因素研究综述

土壤入渗特性是评价土壤水源涵养作用和抗侵蚀能力的重要指标,也是模拟土壤侵蚀过程的基本输入变量,受制于许多外在和内在因素的影响。综述了影响土壤入渗特性的主要因素,这些因素主要有土壤理化性质、下垫面性质、降雨强度、水质及水温等。并提出了今后应该加强研究的内容。     

受雨害小麦籽粒物性与吹泡特性相关性分析

小麦经粒径分级和重力分选,吹泡特征值发生了变化。由于粒径较大的籽粒较易受到雨害,影响其品质,粒径分级后,其吹泡特征值变化显著,分级效果明显。再经重力分选后,从分选出口I~V试样的容重依次增大,并且随着容重增加,吹泡特征值出现不同趋势,分选效果有明显差异。籽粒容重与弹性(P)和配置比(P/L)呈显著正相关,与延伸性(L)和延伸能力(G)呈显著负相关性,而与烘焙强度(W)和弹性指数(Ie)的相关性不明显。采用密度的线性模型描述吹泡特性可达到很高的拟合精度。     

辽西北沙地流动沙丘土壤水分时空变化特征研究

以辽西北沙地流动沙丘为对象,研究了土壤水分运动的时空变化特征。结果表明：流动沙丘土壤含水率的时间变化与降雨有密切关系,春季土壤含水率较低,为0.1%~3.1%;夏季土壤含水率较高,为2.5%~5.1%;秋季土壤含水率略高于春季,为2.2%~3.6%。土壤含水率垂直变化位为：0~10cm土壤含水率变异程度较大,受降雨和蒸发影响强烈;10cm~80cm变异程度相对小些;80cm~120cm土壤含水率比较稳定。流动沙丘不同部位的土壤含水率受干沙层厚度频繁变化和降雨量影响显著,阴坡底含水率＞阳坡底＞阳坡中＞丘顶＞阴中。     

轮耕对双季稻田耕层土壤养分库容及Cd含量的影响

研究长期不同耕作措施下双季稻田土壤结构、养分及重金属含量的变化规律,对构建稻田合理耕层、提升耕地质量、促进粮食可持续丰产具有重要意义。2005-2014年在湖南醴陵双季稻田设置长期免耕(NT-NT)、长期旋耕(RT-RT)、长期翻耕(CT-CT)、翻免轮耕(CT-NT)和旋免轮耕(RT-NT) 5种耕作方式定位试验,测定并分析不同耕作方式对耕层深度、土壤容重、土壤C、N、P、K养分含量、养分库容量及重金属Cd含量等的影响。结果表明,NT-NT由于长期没有动土,土壤容重较高,而RT-RT、CT-CT、CT-NT和RT-NT均使土壤容重值降到了较理想区间。CT-NT和RT-NT 0~5 cm耕层土壤有机碳、活性有机碳、全氮、碱解氮、有效磷、速效钾和Cd含量均显著低于NT-NT,而高于RT-RT、CT-CT,说明NT-NT在促进土壤养分向表层聚集的同时,也促进了土壤镉向表层聚集,且随着耕作频率的增加土壤表层养分及土壤镉均呈下降趋势。CT-NT和RT-NT 5~10 cm耕层土壤各养分含量均显著高于NT-NT,而10~20 cm耕层土壤各养分含量均低于RT-RT、CT-CT,说明轮耕促进了土壤养分积累并主要向土壤中层聚集。耕层厚度、有效养分总库容量及土壤Cd含量均表现为RT-RT、CT-CT>CT-NT、RT-NT>NT-NT,说明随着耕作频率减少土壤耕层逐渐变浅,有效养分总库容量逐渐变小,土壤总镉、有效镉含量也逐渐降低。本研究表明,长期免耕和长期翻(旋)耕均存在一定弊端,长期免耕虽然降低了土壤镉含量,但同时也降低了土壤养分库容,长期翻(旋)耕虽然增加了土壤养分库容,但同时也增加了土壤镉含量,而合理土壤轮耕既可改善土壤结构,促进土壤养分积累、增加土壤养分库容,又能适当降低土壤镉含量,改善土壤环境。     

衡阳紫色土丘陵坡地植被恢复模式对土壤渗透性的影响

土壤渗透性受制于许多外在与内在的因素,与植被类型、土壤性质等关系密切。为探讨不同植被恢复模式对土壤渗透性能的影响,以裸地为对照,以土壤初渗率、稳渗率、平均渗透率与渗透总量表征土壤渗透性,对衡阳紫色土丘陵4种不同植被恢复模式的渗透性及其与土壤物理性质进行研究。结果表明：（1）4种植被恢复模式的土壤渗透性均优于裸地,各植被恢复模式土壤渗透性能大小依次为：枫香×苦楝＞牡荆×刺槐＞紫薇×糯米条＞狗尾草×狗芽根＞裸地,且初渗率、稳渗率、平均渗透率与渗透总量的关系符合方程：α=0.4865α1+0.4982α2+0.5123α3+0.5202α4（其中,αi为指标的标准化数据）;（2）Horton水分入渗模型拟合的相关系数R2值≥0.775,对所研究的区域的土壤水分入渗过程具有较好的适用性;（3）相关分析表明：土壤渗透性与＞2 mm的土壤组成的百分比、2~0.25 mm土壤组成的百分比、毛管百分比、非毛管百分比和饱和导电率为呈显著或极显著正相关,与土壤容重为呈显著或极显著负相关,与土层深度和＜0.25 mm土壤组成的百分比相关性不明显。     

基于灰色关联法土壤水分垂直入渗影响因素研究

土壤水分入渗过程中主要受压力水头、土壤初始含水率、土壤容重、颗粒级配影响。基于一维垂直土柱积水入渗试验研究这些因素对入渗能力影响的主次关系,利用Green-Ampt与Philip入渗模型得到相应土壤入渗特性参数,采用灰色关联分析法研究四个因素对累积入渗量、饱和导水率、稳定入渗率、湿润锋面吸力、吸渗率的影响程度。结果表明,压力水头、土壤初始含水率、土壤容重、颗粒级配对累积入渗量、入渗率及Green-Ampt与Philip模型中物理参数有显著影响,各处理中饱和导水率与稳定入渗率间误差较小,吸渗率拟合值与利用湿润锋面吸力所得吸渗率计算值间相似程度较高,决定系数R2大于0.85;灰色关联分析结果表明,颗粒级配关联度均值r4最高为0.946 3,土壤容重、初始含水率其次,压力水头影响程度最小（r1=0.562 9）。总而言之,颗粒级配对土壤入渗特性影响起主导作用,该研究成果可为农业灌溉及水资源管理提供理论支撑。     

太行山低山丘陵区不同土地利用条件下土壤容重空间变化特征

通过对太行山低山丘陵区人工立体石榴林工程的调查,结果表明：不同土地利用类型土壤容重值大小依次为：坡谷石榴地（1.16 g/cm3）﹤中坡石榴地（1.27 g/cm3）﹤坡谷台田（1.30 g/cm3）﹤中坡草地（1.32 g/cm3）;中坡位土壤容重值大于坡谷;耕作层（0～20㎝）土壤容重在台田和草地之间以及石榴地之间没有明显差异,坡谷石榴地的土壤容重值最低（1.32 g/cm3 ）,中坡草地的土壤容重最高（1.56 g/cm3）,深层土壤（40～60㎝）的土壤容重在相同坡位没有明显差异。土壤容重随着采样深度增加的总趋势,但坡谷台田和中坡草地土壤容重在10～20㎝土层最低;统计表明0～5cm、10～20cm土壤容重属于中等变异性,其余土层土壤容重属于弱变异性。本文从土地利用类型和坡位来分析土壤容重空间变化特征,对于其它影响因子的影响有待于进一步的研究。     

Cropping system effects of maize on infiltration,runoff and erosion on loess soils in South-Limbourg (The Netherlands): A comparison of two rainfall events

Two natural rainfall events are compared to evaluate the effects of three cropping systems of silage maize on soil moisture content, infiltration, runoff and erosion. Both rainfall events took place in early summer. One was a low intensity event with 27.6 mm of rain in 9 hours, and the other a high intensity event with 33.4 mm in 42 minutes. Cropping systems were:

• 1.(I) a spring tilled system (conventional),
• 2.(II) an autumn and spring tilled system with summer barley as spring cover crop, and
• 3.(III) an autumn tilled system with winter rye as winter cover crop and direct drilling of silage maize.

During the low intensity event, soil moisture content of the top 5 cm rose to field capacity on all three cropping systems. No runoff was generated. During the high intensity event, soil moisture content rose to field capacity on the two spring tilled cropping systems but was only slightly raised in the direct drill system, in spite of 17.7 mm of infiltrated rain. Runoff coefficients of the high intensity event were 41.7% (conventional system), 14.9% (autumn and spring tilled system) and 47.0% (direct drill system). The direct drill system showed a severely slaked soil surface in early summer, caused by winter rain.The response to rainfall of soil moisture content is ascribed to:

• 1.(I) a predominance of matrix infiltration on all cropping systems during the low intensity event and on the spring tilled systems during the high intensity event, and
• 2.(II) a predominance of infiltration via continuous macropores, open to the surface (of biologic origin), by-passing the soil matrix, on the direct drill system during the high intensity event.

The presence of continuous, vertical macropores on the direct drill system explains its surprisingly high infiltration capacity, considering its strongly slaked appearance. The smooth soil surface of the direct drill cropping system may have delayed infiltration during the flooded stage of the high intensity event by not providing vent points for the escape of soil air. Soil loss from the direct drill system during the high intensity event was only 15.6% of that from the conventional system. This is ascribed to low detachment rates of soil material by drop impact and/or overland flow, due to the presence of winter rye remains and, especially, the relatively high soil surface shear strength of the direct drill cropping system in early summer.     

不同耕作方式对土壤水分蓄持能力的影响

为了改善北京地区农田土壤结构,提高土壤蓄水保墒能力,提升农田生产能力,增加作物产量,本项目自2009年开始在北京市延庆县保护性耕作试验田开展农田深松效果研究,对比分析了免耕和免耕+深松2种技术模式对土壤容重、含水率、水分入渗率的影响。结果表明,与免耕处理相比,免耕+深松技术模式0~30 cm图土层内,土壤容重降低了约3.4%,稳定入渗率提高了62.5%,在0~100 cm土层内平均质量含水量增加5.9%,因此深松可提高土壤蓄水保墒能力,有助于农作物的生长。     

The Effect of Different Soybean Tillage Systems on Infiltrability and Erosion Susceptibility of an Oxisol in Paraná, Brazil

Measurements of infiltrability were carried out during the soybean vegetation period in three different tillage systems on an Oxisol, with the aim of estimating relative erosion susceptibility. The tillage systems studied were conventional tillage (disc plow), minimum tillage (chisel plow) and no-tillage. Infiltration was determined as the difference between rainfall applied with a portable rainfall simulator and runoff collected from mini-plots.
During all growth stages of the soybeans, infiltrability under no-tillage was higher than under conventional tillage. Minimum tillage took an intermediate position. Lowest overall infiltrability and consequently, highest relative erosion susceptibility was observed in the early growth stage after planting, in a wet year, when the degree of soil cover was also lowest. Infiltrability was mainly affected by degree of surface seal development as a result of natural rainfall energy the soil surface had received prior to measurements, as well as degree of soil cover. Highly significant correlations were found between the calculated sum of erosivity indices one month before measurement and the total infiltration. Differences in bulk density and macroporosity had hardly any effect on infiltrability.
The better performance of no-tillage in controlling erosion observed in Brazil can thus be explained by the higher degree of soil cover in comparison to the other tillage systems studied.     

吉林省西部盐碱地5种林分类型土壤改良效果研究

为揭示吉林省西部盐碱地不同林分类型的土壤改良效果,以松原市乾安县分布的柽柳林、黑杨林、油松林、黑杨白榆混交林及枸杞林5种典型林分为研究对象,未造林地作为对照,通过野外调查与室内分析相结合,对各林分0~30 cm土层深度的土壤理化性质进行分析。结果表明：5种林分对土壤理化性质均有一定程度的改善,与未造林地相比,5种林分均表现为土容重减小,孔隙度增加,土壤渗透性能得到改善。各林分对0~10 cm表层盐碱土pH有明显的降低作用,与对照相比降低了3.69%~7.50%。林地土壤养分含量与未造林地相比有显著提升,各土层深度林地土壤有机质、全氮、水解氮、全磷、有效磷、全钾、速效钾含量均大于未造林地,土壤养分主要集中于0~20 cm土层深度,呈表聚现象。通过主成分分析法对14个土壤改良评价指标进行综合评价,其综合得分由大到小依次为：枸杞(43.81)>柽柳(40.79)>黑杨白榆混交林(40.33)>黑杨(39.31)>油松(39.03)>未造林地(33.55)。结果表明5种人工林均能够改善土壤理化性质,在吉林省西部地区通过植被恢复进行盐碱地改良时,可考虑枸杞与柽柳为优选树种。