延安新区生态林建设对土壤理化性质的影响

树木定植可以影响土壤理化性质。为明确延安新区不同树种人工生态林对土壤理化性质的影响状况,为合理造林提供依据,以延安新区荒地土壤为对照,研究了人工生态林(松树、柏树)对土壤理化性质,包括含水量、p H值、有机质、铵态氮和硝态氮含量的影响。结果表明:人工林增加了土壤含水量,且随着土壤深度的增加,土壤含水量变化总体呈现出增加的趋势。土壤的p H值总体上是呈弱碱性,松树定植土壤p H值呈现降低趋势,柏树和荒地土壤p H值在不同土层中变化较大。土壤有机质的含量随深度增加呈递减的趋势,不同土层中呈现荒地柏树松树。荒地土壤铵态氮在不同土层中变化不大,柏树土壤中0~15 cm随深度的增加而增加,15~20 cm略有下降;松树土壤在0~10 cm土层基本相同,10~15 cm有所下降,15~20 cm略微上升。硝态氮在不同类型利用方式下变化不一,造成这种差异可能与树种有关。     

采煤沉陷干扰下土壤理化性质的演变——以大柳塔矿采区为例

为了解采煤沉陷影响下土壤理化性质的变化规律,及不同土壤基质对采煤沉陷的反应,在神木县大柳塔矿采区,分别对五个年份的6个沉陷区及其对照区进行土壤理化指标进行了测定并分析。结果表明:随沉陷年限的增加,土壤容重减小,随土层深度的增加沉陷区与对照区容重变化基本一致。土壤粘粒含量随沉陷年限的增加而增加,随土层深度的增加呈由大到小的趋势,土壤砂粒含量变化与之相反。土壤pH值随沉陷年限的增加而降低;有机质、全氮、全磷、全钾含量随沉陷年限的增加而增大;全钾在沉陷1年后显著增大,与有机质、全氮、全磷变化趋势不一致。相对于硬梁地,采煤沉陷对沙地影响较大。沉陷16年的沙地土壤理化性质与对照区基本趋于一致。     

滴灌条件下脱硫石膏对盐碱土改良效果及安全性的影响

为实现燃煤烟气脱硫废弃物再利用,使其能运用于新疆大面积盐碱地改良,在新疆农八师134团盐碱地施用脱硫石膏,研究滴灌条件下脱硫石膏对盐碱土壤理化性质以及土壤重金属含量的影响,评估脱硫石膏改良盐碱土的可行性和安全性。结果表明:盐碱地施用脱硫石膏后土壤容重降低,>0.25mm团聚体数量增加,土壤孔隙度增加;土壤pH值、碱化度和电导率降低,尤其在0-10cm、10-20cm土层改善效果明显;土壤中Na~+、Cl~-含量降低,0-10cm土层较其他土层Na~+含量下降明显,于对照相比下降40.62%,表层土壤中Ca~(2+)、SO_4~(2-)含量增加,有利于降低土壤盐碱危害;施用脱硫石膏对土壤Hg含量没有影响,Cr元素含量下降,各项重金属元素含量均远低于国家环境二级标准,说明施用脱硫石膏不会对土壤造成重金属污染。综上所述,脱硫石膏对盐碱地有一定的改良效果且不会对土壤安全造成威胁。     

黄土区不同退耕年限草地土壤分离速率及其理化性质

以子午岭连家砭林场不同退耕年限草地为研究对象,以撂荒地为对照,通过野外调查和室内测试分析,研究了退耕12 a、18 a、24 a、36 a草地土壤分离速率及其理化性质。结果表明:草地土壤分离速率与同一土层的撂荒地相比明显降低,并随着退耕年限增加而降低。不同退耕年限草地土壤容重、有机质含量、水稳性团聚体含量、根系生物量密度均有不同程度的改变,且表层土壤(0~20 cm)理化性质改善最为显著(P0.05);不同退耕年限草地土壤分离速率与其理化性质均呈显著相关关系(P0.05),但对于不同退耕年限草地,影响土壤分离速率的主导因子不同。     

弃耕地植被恢复过程中土壤理化性质演变趋势研究

通过对安塞纸坊沟流域14块不同弃耕年限的草地土壤理化性质的研究表明:随着弃耕地植被的恢复,土壤容重降低、孔隙度增大、质地改善;土壤有机质含量、CEC、全氮含量、全钾含量、水解氮及速效钾含量逐步提高,土壤盐分含量、土壤pH值有逐步降低的趋势,说明随着植被的恢复,土壤理化性质在不断优化.另外植被生物量与土壤有机质、CEC、全钾、速效钾、全氮及水解氮均呈极显著正相关,与土壤pH值与土壤容重呈极显著负相关,说明土壤与植被具有互动效应.     

放牧对荒漠灌丛草地土壤团聚体组成及其稳定性的影响

以内蒙古阿拉善盟荒漠草地为研究对象,分析了不同放牧强度对土壤理化性质、团聚体组成、养分含量及其稳定性的影响.结果表明:与轻度放牧相比,重度放牧使0～5 cm、5～10 cm和10～20 cm土层土壤有机C和全N含量显著降低,土壤容重显著增加;各土层中土壤团聚体以0.053～0.25 mm粒径为主,放牧强度的增加造成土壤...     

连作年限对土壤理化性质及酶活性的影响

以新疆北疆博乐市精河县托托乡连作5年、10年、15年、20年和30年的棉田土壤为研究对象,应用Pearson相关分析方法对不同连作年限棉田土壤基本理化性状及酶活性进行了分析。结果表明:棉花连作对土壤理化性质及酶活性有较大影响,土壤pH、有机质、全氮与四种土壤酶相关性较好,是影响酶活性的重要因子;随着连作年限增加,过氧化氢酶、蔗糖酶活性增强,磷酸酶、脲酶活性降低;不同种土壤酶随土层厚度的增加酶活性逐渐降低,并在三个土层中存在显著差异;棉田连作对土壤理化性质及酶活性的影响有利也有弊,在评价土壤肥力状况方面,某些土壤酶可以作为土壤生化过程强度的较好指标。     

华家岭防护林带土壤理化特性研究

采用实地调查取样与室内常规分析相结合的研究方法,对华家岭防护林带的土壤理化性质进行了测定和分析。结果表明:林分类型和林龄会影响土壤理化性质,表现为:云杉纯林土壤物理性质明显优于油松、杨树纯林;各林分土壤速效N、K,全量N、P、K及土壤有机质平均含量均为云杉纯林﹥杨树纯林﹥油松纯林,土壤速效P平均含量为云杉纯林﹥油松纯林﹥杨树纯林;随林龄的增加,云杉林的平均毛管孔隙度有所改善,土壤的通气性和透水性逐步提高,涵养水源能力有所增强。除速效P、全量K外,云杉林的各项土壤化学指标随林龄的增加均有不同程度的提高。     

二甲基二硫的生物活性评价及对土壤养分的影响

采用室内生物活性测定方法,评价二甲基二硫(dimethyl disulfide,DMDS)对土壤病原线虫和土传病原菌的毒力,比较不同浓度药剂处理对土壤理化性质和土壤呼吸的影响,为探究DMDS作为新型土壤熏蒸剂提供切实可行性的依据。结果表明:DMDS熏蒸对土传病原线虫和镰刀菌属的LD_(50)分别为4.743 mg/kg和1.513 mg/kg,可见DMDS对病原线虫和镰刀菌有良好的生物活性。对土壤理化性质进行数据分析发现:DMDS能显著增加土壤铵态氮含量,抑制硝化作用过程,减少NO~-_3-N的产生,提高植物可吸收态氮素水平。DMDS处理的土壤有机质含量和电导率均显著高于对照土壤,而土壤pH和速效钾含量较对照均有降低。此外,熏蒸土壤中有效磷含量较对照减少,但两者无显著差异。对DMDS熏蒸后土壤进行底物诱导呼吸试验,表明DMDS能够在试验初期抑制土壤微生物生物量。本试验结果可为指导DMDS的科学使用提供理论依据及对土壤微生物活性的影响作出科学评价。     

红火蚁入侵对荔枝园土壤性理化质的影响

对红火蚁Solenopsis invicta Buren荔枝园发生区土壤理化性质进行了研究,结果表明:3类红火蚁不同发生区之间、红火蚁蚁巢4个不同方位之间以及距红火蚁蚁巢中心不同距离之间的土壤各项理化性质均有显著的差异(p<0.01)。从对照区、轻度发生区到重度发生区土壤粘粒变得越来越细,酸性逐渐升高。土壤有机质、碱解N、有效P的含量在轻、重度发生区较对照区分别下降了29.0%与39.9%、42.1%与53.6%、43.3%与52.6%,但速效K的含量在轻、重度发生区较对照区则分别升高了8.5%与34.0%。此外,在红火蚁发生区,蚁巢上的土壤理化性质与蚁巢以外的土壤理化性质明显不同(p<0.01)。蚁巢上的土壤明显比蚁巢以外的土壤酸性强。土壤有机质、碱解N、有效P的含量在蚁巢上明显最小,但土壤速效K的含量在蚁巢上明显最高。蚁巢不同方位上土壤的理化性质相对差异较小,红火蚁在荔枝园的分布存在一定的空间随机性。     

人工植被下风沙土演变研究综述

在流沙上建立了人工植被可以促进风沙土的成土发育。本文概述了人工植被风沙土与流沙的理化性质,微物,土壤酶的差异及其演变趋势。     

Effect of sand-fixing vegetation on the hydrological regulation function of sand dunes and its practical significance

Soil water content is a key controlling factor for vegetation restoration in sand dunes. The deep seepage and lateral migration of water in dunes affect the recharge process of deep soil water and groundwater in sand dune ecosystems. To determine the influence of vegetation on the hydrological regulation function of sand dunes, we examined the deep seepage and lateral migration of dune water with different vegetation coverages during the growing season in the Horqin Sandy Land, China. The results showed that the deep seepage and lateral migration of water decreased with the increase in vegetation coverage on the dunes. The accumulated deep seepage water of mobile dunes (vegetation coverage<5%) and dunes with vegetation coverage of 18.03%, 27.12%, and 50.65% accounted for 56.53%, 51.82%, 18.98%, and 0.26%, respectively, of the rainfall in the same period. The accumulated lateral migration of water in these dunes accounted for 12.39%, 6.33%, 2.23%, and 7.61% of the rainfall in the same period. The direction and position of the dune slope affected the soil water deep seepage and lateral migration process. The amounts of deep seepage and lateral migration of water on the windward slope were lower than those on the leeward slope. The amounts of deep seepage and lateral migration of water showed a decreasing trend from the bottom to the middle and to the top of the dune slope. According to the above results, during the construction of sand-control projects in sandy regions, we suggest that a certain area of mobile dunes (>13.75%) should be retained as a water resource reservoir to maintain the water balance of artificial fixed dune ecosystems. These findings provide reliable evidence for the accurate assessment of water resources within the sand dune ecosystem and guide the construction of desertification control projects.     

科尔沁沙地坨甸交错区土壤水分的空间变异规律

科尔沁沙地沙丘-草甸相间地区,地貌形态多样、土地利用类型众多,从而导致土壤水分空间分布的复杂性。通过对科尔沁沙地典型沙丘-草甸相间地区的调查取样与试验分析,运用统计学理论和方法,研究土壤水分的空间变异性及其空间分布规律。结果表明：水平方向上,土壤水分总体表现为草甸地大于沙丘地,过渡带介于两者之间。就草甸地而言,植物生长越好,其土壤水分越高,保水持水性能也越好;沙丘地则与之相反,植被最稀疏的流动沙丘,其土壤含水量大于半流动半固定沙丘与固定沙丘,且有良好的储水条件。垂向上,高覆盖草甸、低覆盖草甸和农田（草甸）土壤含水量在地表下0～40 cm波动最大,40～160 cm随深度增加而递增;流动沙丘、半流动沙丘和固定沙丘土壤含水量随深度增加呈微弱加大趋势。林地、撂荒地、农田（沙丘）变化程度居中。从空间分布看,研究区中东部土壤水分偏大,且向南北两侧区域递减。     

库布齐沙漠穿沙公路沙害综合防治技术

库布齐穿沙公路修建在库布齐沙漠高大的流动沙丘区 ,风沙流侵袭与沙丘整体前移埋压公路是主要沙害形式。现有防沙措施是沙障保护下的人工植被及天然植被相结合的综合防护体系 ,固沙及阻沙效益明显。目前要解决的是尽快形成公路两侧稳定的植被群落 ,以保证公路的长期畅通     

Effects of different plantation types on soil properties after vegetation restoration in an alpine sandy land on the Tibetan Plateau,China

Large areas of Artemisia ordosica Krasch., Caragana korshinskii Kom., and Caragana intermedia Kuang and H. C. Fu plantations were established on moving sand dunes in the Gonghe Basin(northeastern Tibetan Plateau) for vegetation restoration. Elevating our understanding of the changes in soil characteristics after the establishment of different plantation types can be useful in the context of combating desertification. To assess the effects of these plantation types on the restoration of sandy land, we measured soil physical-chemical properties at four depths(0–5, 5–10, 10–20, and 20–50 cm) in each of the three plantation types and also in non-vegetated moving sand dunes(as control sites). Generally, the establishment of A. ordosica, C. korshinskii and C. intermedia plantations on sand dunes has greatly ameliorated soil quality in the Gonghe Basin. Specifically, relative to the moving sand dunes, shrub plantation has increased the silt and clay contents, total porosity and water holding capacity, soil organic matter, total nitrogen, total phosphorus and total potassium contents. The calculated soil quality index suggested that in the Gonghe Basin, C. intermedia is the best choice for soil amelioration. In all the three plantation types, soil amelioration mainly occurred in the shallow depths.     

科尔沁沙地乌兰敖都地区荒漠化动态监测

利用科尔沁沙地乌兰敖都荒漠化试验站的监测资料,从植被、土壤、水分、气象和沙尘暴等方面分析了乌兰敖都地区的荒漠化发展动态.结果表明:近10年内气温有暖温化趋势,但灾害天气没有明显增加;流动沙丘侵蚀最严重,沙丘平均移动速率为2.2 m/a;人工植被发展良好,但原生草场的可持续发展能力有所下降;地下水位没有明显下降趋势.目前,科尔沁沙地乌兰敖都地区土地荒漠化呈逆转趋势,整体环境有所改善.     

不同植被覆盖度沙垄土壤化学性质的空间分异

为了研究温带固定半固定沙漠土壤化学性质与地表植被的关系,本文以古尔班通古特沙漠西南缘莫索湾地区沙漠–绿洲过渡带为研究区,分别选取植被覆盖度为10%和15%的半固定沙垄及植被盖度为30%的固定沙垄。采集了各沙垄不同地貌部位的土壤样品,室内测试了土壤pH、电导率、有机质、全氮和全磷等指标。结果表明：① 随着植被覆盖度下降,沙垄西坡、坡顶和东坡,土壤pH、电导率、有机质、全氮和全磷呈逐渐降低趋势;② 不同地貌部位的分布格局各沙垄表现不一致,沙垄A和沙垄B的 pH、电导率、有机质、全氮和全磷含量最大值均出现在垄间地,其他部位之间没有明显的规律,沙垄C 的pH和电导率最大值出现在垄间地,而土壤养分含量于坡顶部位富集;③ 各沙垄不同土层土壤性质分布规律相对一致,土壤pH、电导率随着土层深度的增加呈上升的趋势,而土壤养分随着土层深度的增加而降低;④ 土壤化学性质空间分布异质性与植被的分布格局密切相关,相互影响,当植被覆盖度较高时,生物作用起主导作用,当植被覆盖度较低时,风蚀、地形等非生物因素作用加强,影响生物作用,植被对土壤颗粒和养分的拦截及富集作用逐渐减弱或消失。     

Spatial heterogeneity of soil water content in the reversion process of desertification in arid areas

Sandy soils in arid,rain-fed environments have low and limited water content,which is a principal factor limiting vegetation development,and a key constraint controlling the structure and functions of the ecological systems in arid areas.The spatial heterogeneity of soil water content is a major soil property,and a focus of soil science and hydrology.On the southern edge of the Tengger Desert,sample plots were selected from mobile sand dunes in desertified lands that had been enclosed for 5,15 and 25 years,respectively.This study explored the dynamic and spatial heterogeneity of soil water content in these different layers of soil that were also in the reversion process of desertification.The results showed that the soil water content of the mobile sand dunes was highest when in the initial stages of the reversion process of desertification,while the soil water content in the 0-20 cm,20-40 cm and 40-60 cm layers of soil was 1.769%,3.011%,and 2.967% respectively,presenting a restoring tendency after 25 years of enclosure.There were significant differences,as a whole,in the soil water content among different restoration stages and different soil layers,respectively.Changes in soil water content,in different soil layers,at different restoration stages,exhibited exponential or spherical patterns.The spatial distribution of soil water content exhibited a mosaic patch pattern with obvious spatial heterogeneity.The ratio of the heterogeneity of spatial autocorrelation to gross spatial heterogeneity was greater than 50%.The gross spatial heterogeneity of the 0-20 cm layer of soil improved gradually,while those of the 20-40 cm and 40-60 cm layers improved initially,then weakened in the reversion process of desertification.This study revealed that restoration with sand-binding vegetation reduced soil water content,and increased its spatial heterogeneity in arid areas.However,after 25 years of vegetation-soil system restoration,the soil water content started to increase and its spatial heterogeneity started to weaken.These results will further benefit the understanding of the ecological mechanism between soil water and sand-binding vegetation.     

不同植被覆盖度沙垄土壤化学性质的空间分异

为了研究温带固定半固定沙漠土壤化学性质与地表植被的关系,本文以古尔班通古特沙漠西南缘莫索湾地区沙漠-绿洲过渡带为研究区,分别选取植被覆盖度为10%和15%的半固定沙垄及植被覆盖度为30%的固定沙垄。采集了各沙垄不同地貌部位的土壤样品,室内测试了土壤pH、电导率、有机质、全氮和全磷等指标。结果表明:①随着植被覆盖度下降,沙垄西坡、坡顶和东坡,土壤pH、电导率、有机质、全氮和全磷呈逐渐降低趋势;②不同地貌部位的分布格局各沙垄表现不一致,沙垄A和沙垄B的pH、电导率、有机质、全氮和全磷含量最大值均出现在垄间地,其他部位之间没有明显的规律,沙垄C的pH和电导率最大值出现在垄间地,而土壤养分含量在坡顶部位富集;③各沙垄不同土层土壤性质分布规律相对一致,土壤pH、电导率随着土层深度的增加呈上升的趋势,而土壤养分随着土层深度的增加而降低;④土壤化学性质空间分布异质性与植被的分布格局密切相关,相互影响,当植被覆盖度较高时,生物作用起主导作用,当植被覆盖度较低时,风蚀、地形等非生物因素作用加强,影响生物作用,植被对土壤颗粒和养分的拦截及富集作用逐渐减弱或消失。     

Biological soil crust distribution in Artemisia ordosica communities along a grazing pressure gradient in Mu Us Sandy Land,Northern China

This study investigated the distribution pattern of biological soil crust (BSC) in Artemisia ordosica communities in Mu Us Sandy Land. Three experimental sites were selected according to grazing pressure gradient. In each experimental site, the total vegetation cover, A. ordosica cover, BSC cover, litter-fall cover, BSC degree of fragmentation, BSC thickness and soil properties were investigated in both fixed and semi-fixed sand dunes and simultaneously analyzed in the laboratory. The results showed that at the same grazing pressure, BSC cover and composition were significantly affected by the fixation degree of sand dunes. In addition, BSC cover in the fixed sand dunes was 83.74% on average, whereas it is proportionally dominated by 28% mosses, 21% lichens, and 51% algae. Meanwhile, BSC cover in the semi-fixed sand dunes was 23.54% on average, which is proportionally dominated by 6.3% mosses, 2.5% lichens, and 91.2% algae. Fine sand, organic matter, and total nitrogen (N) contents in the fixed sand dunes were all significantly higher than those in the semi-fixed sand dunes. Litter-fall cover decreased along the grazing pressure gradient, whereas BSC fragmentation degree increased. Fine sand content decreased along with the increase of grazing pressure, whereas medium sand content increased in both fixed and semi-fixed dunes. The organic matter and total N contents in the no grazing site were significantly higher than those in light and normal grazing sites. However, there were no significant differences between the light and normal grazing sites. In addition, there were also no significant differences in BSC thickness between the light and normal grazing sites in the fixed sand dunes. However, a significant decrease was observed in both BSC cover and thickness in the normal grazing site. The BSC in the semi-fixed dunes was more sensitive to disturbance.