The impact of vegetative cover type on runoff and soil erosion under different land uses

The effects of different vegetation types on runoff generation and soil erosion were investigated. The study was conducted at the Southern part of West Bank, about 10 Km north-west of Hebron city, during 2005, 2006 and 2007. Five treatments were implemented; forests planted with P. halepensis (F), natural vegetation dominated by S. spinosum (W.S), natural vegetation where S. spinosum was removed (W/o.S), cultivated land (C), and deforestation (Df). Three types of data were estimated in each plot: runoff after each rainfall event, sedimentation at the end of the rainy season, and chemical and physical soil properties. The obtained results indicate that there are significant and important differences in runoff generation and sediment production with respect to the different types of vegetative cover. Forest and natural vegetation dominated by S. spinosum treatments exhibited the lowest amounts of runoff, with averages of 2.02 and 1.08 mm, respectively, in comparison to other treatments. The removal of S. spinosum significantly increased the total amount of runoff and sedimentation compared to the forest and S. spinosum treatments. In addition, runoff significantly increased (4.03 mm) for the Df treatment compared to that of the forest site. The greatest amount of sedimentation was observed in cultivated land and with deforestation.     

宁南山区不同土地利用方式土壤酶活性特征研究

试验研究不同土地利用方式土壤酶活性特征结果表明,天然草地表层土壤酶活性较高,灌木林地和人工草地次之,果园和农地较低;20~40cm土层果园和农地土壤酶活性稍高;天然草地和灌木林地对土壤酶活性改良效果显著,而果园和农地则较差;土壤蔗糖酶活性在剖面上变化明显,脲酶和碱性磷酸酶活性变化趋势大多一致,过氧化氢酶活性在不同土地利用类型和剖面层次上均无明显差异。土壤蔗糖酶、脲酶和碱性磷酸酶活性互呈极显著正相关,且均与速效氮及有机质呈极显著正相关。土壤酶活性可作为较理想的土壤肥力指标。     

晋西黄土区不同地类土壤抗冲性分析

为了评价植被对土壤抗冲性的影响,以晋西黄土区蔡家川流域刺槐林、油松林、次生林、退耕荒草地、农地、土质路面为研究对象,采用野外实地放水冲刷法,以侵蚀量为指标,研究不同地类土壤的抗冲性,并分析地被物、根系与土壤抗冲性的相关性.结果表明:不同地类的土壤抗冲性为次生林＞刺槐林＞油松林＞退耕荒草地＞土质路面＞农地;单位面积上枯落物量及其厚度对土壤抗冲性的影响最大;土壤表层根系对土壤抗冲性也具有较大影响,能够有效提高土壤抗冲性的根系结构是0～30 cm土层中的毛根,其中,影响最大的是表层0～10 cm的根系,单位体积土壤内的根系越多,土壤抗冲性越强.     

浙江省杭州湾地区城市规划对耕地保护的潜在影响

以浙江省沿杭州湾经济快速发展地区为例,结合土地利用现状、城市规划和农用地分等数据,利用GIS空间分析方法,探讨了该地区未来城市建设用地扩展及其对耕地数量和质量的潜在威胁。结果表明：研究区是浙江省耕地资源分布相对集中且质量较高的地区,规划期间建设用地扩展迅速,新增用地面积达9.4×104 hm2;按照现有规划,研究区将减少耕地面积7.1×104 hm2,耕地是规划新增建设用地的主要来源,约占75%;优质耕地的减少量大,减少速度快,一至五等耕地的减少量占67.5%,一、二等耕地到2020年将分别减少37.16%和35.52%。建议应用农用地分等成果对规划占用的耕地进行质量评价,调整规划方案,减少建设对耕地数量质量的影响,保障粮食生产能力。     

南方红壤区不同利用土地产流产沙特征试验研究

研究不同类型降雨下土地利用/覆被对水土流失过程的影响,对于科学指导植被建设和控制水土流失具有重要意义。采用人工模拟降雨的方法,对南方红壤区典型小流域8种不同利用土地的径流、泥沙在不同降雨条件下的流失特征进行了研究。结果表明,不同利用土地的径流和泥沙流失差异明显,且各利用土地的径流和泥沙流失的变化对雨量雨强变化的响应不同;相同降雨条件下径流调控排序为果园>旱平地>油茶>弃土场>水保林>坡耕地>水田>裸地,泥沙调控排序为果园>油茶>旱平地>水田>裸地>水保林>坡耕地>弃土场。因此,具有水土保持措施的果园保水保土最好,而裸地产流最大,坡耕地和弃土场泥沙流失最多,产流和产沙没有完全的对应关系,该研究结果为南方红壤区的水土保持规划与水土流失综合治理提供了基础数据和科学依据。     

The effect of organic matter on the structure of soils of different land uses

In this study, the soil structure of two soils (Haplic Chernozem and Eutric Fluvisol) of different land uses (forest, meadow, urban and agro-ecosystem – consisted of four crop rotations) in Slovakia was compared. The soil aggregate stability was determined with a dependence on the chemical composition of plant residues. The quantity and quality of the organic matter was assessed through the parameters of the C and N in size fractions of dry-sieved and water-resistant aggregates. The soil structure of the forest ecosystem was evaluated as the best of all of forms of land use. Differences in the soil structure under the grass vegetation of a meadow (natural conditions) and urban ecosystem were also recorded. The agro-ecosystem was characterised by a higher portion (55.95%) of the most valuable (agronomically) water-resistant aggregate size fraction of 0.5–3 mm. Values of the carbon management index showed that the larger water-resistant aggregates were, the greater were the changes in the organic matter (r = ?0.680, P < 0.05). In addition, a smaller content of dry-sieved aggregates of the 3–5 mm size fraction was observed with higher contents of soil organic carbon (SOC) (r = ?0.728, P < 0.05) and labile carbon (C_L) (r = ?0.760, P < 0.05); there were also greater changes in the soil organic matter and vice versa, higher contents of SOC (r = 0.744, P < 0.05) and C_L (r = 0.806, P < 0.05) greater contents of dry-sieved aggregates of size fraction 0.5–1 mm. The soil structure of agro-ecosystem was superior at a higher content of cellulose (r = ?0.712, P < 0.05) in the plant residues. The higher content of cellulose and hemicellulose in the plant residue of a previous crop was reflected in a smaller C_L content in the water-resistant aggregates (r = ?0.984, P < 0.05). A correlation was observed between a high content of lignin in the plant residue and a smaller SOC content in the water-resistant aggregates (r = ?0.967, P < 0.05). Lastly, a higher content of proteins in the plant residues (r = 0.744, P < 0.05) supported a greater content of dry-sieved aggregates of the 0.5–1 mm size fraction.     

排土场不同土地利用类型土壤的分形特征

利用分形理论对排土场人工林、耕地和草地等不同样区土壤颗粒分形特征进行研究,探讨煤炭开发对该区土壤环境的影响程度,为保护矿区土壤生态条件和恢复土壤生态功能提供科学依据.运用欧美克LS-POP（6）激光粒度分析仪测定阜新市海州露天矿排土场土地复垦区3种土地利用类型0～100 cm土层10个层次的土壤颗粒机械组成,运用土壤体积分形模型计算土壤颗粒体积分形维数D,同时测定土壤样品的理化性质.结果表明：1）不同土地利用类型对土壤分形维数影响显著,而土壤层次对土壤分形维数影响不显著;3个样区的D值在2.078 6～2.717 5之间,平均D值为2.424 1.2）不同样区平均D值表现为人工林（2.2457）＜草地（2.5024）＜耕地（2.5476）.3）研究区水解氮、全氮质量分数与土壤分形维数呈多项式曲线关系,速效钾质量分数与土壤分形维数呈对数曲线关系,排土场土壤分形维数D值与土壤全氮、水解氮、速效钾质量分数为负相关,与pH值不存在相关性.     

万柏林区城乡结合部的耕地变化定量分析

应用GIS技术与统计方法对1990～2001年太原市万柏林区城乡结合部的耕地变化进行了定量分析。结果表明：11年间全区耕地转为他用的面积占所有土地转用总和的52.04%。在8类土地利用类型中，耕地转用量最大，面积为766.38 hm²；耕地动态度最高，为2.14%。城区外土地区位优势与建设用地比较利益较大，导致区域内耕地分布重心向城市中心外更远的方向移动，11年共移动了0.95 km；8类土地利用类型中，耕地相对变化率在位于城乡结合部核心区的小井峪乡最高，达2.98。补充耕地时成片开发后备土地使耕地大图斑增多，近城区的零星耕地因建设占用使耕地小图斑减少，致使全区耕地破碎度由0.264减少到0.258，耕地分离度则由0.65上升到0.68，耕地重要度由53.23%下降到44.86%。     

密云水库上游地区不同土地利用方式面源污染试验

为了更合理地利用土地、减少面源污染,利用密云水库上游石匣坡地径流场不同土地利用试验小区的5年观测数据,分析不同土地利用方式对面源污染的影响。研究表明:不同土地利用方式多年平均次径流系数差异明显,依次为清耕休闲地>坡耕地玉米>荒草坡>鱼鳞坑刺槐>水平条山楂,多年平均土壤侵蚀量与径流中TP、TN和CODMn流失量随径流系数的增大而增加,流失量与径流系数呈显著的正相关关系;径流中养分含量与径流系数之间没有显著相关关系。因此,通过增加植被覆盖或改变土地利用方式可大大减轻水土流失及其造成的面源污染。     

中国亚热带中部三峡库区不同土地利用方式下甲烷氧化潜力研究

To compare the CH4 oxidation potential among diferent land uses and seasons,and to observe its response to monsoon precipitation pattern and carbon and nitrogen parameters,a one-year study was conducted for diferent land uses (vegetable field,tilled and non-tilled orchard,upland crops and pine forest) in central subtropical China.Results showed significant diferences in CH4 oxidation potential among diferent land uses(ranging from 3.08 to 0.36 kg CH4 ha-1 year-1).Upland with corn-peanut-sweet potato rotation showed the highest CH4 emission,while pine forest showed the highest CH4 oxidation potential among all land uses.Non-tilled citrus orchard (0.72±0.08 kg CH4 ha-1 year-1)absorbed two times more CH4 than tilled citrus orchard(0.38±0.06kg CH4 ha-1 year-1).Irrespective of diferent vegetation,inorganic N fertilizer application significantly influenced CH4 fluxes across the sites (R2=0.86,P=0.002).Water-filled pore space,soil microbial biomass carbon,and dissolved nitrogen showed significant efects across diferent land uses (31% to 38% of variability)in one linear regression model.However,their cumulative interaction was significant for pine forest only,which might be attributed to undisturbed microbial communities legitimately responding to other variables,leading to net CH4 oxidation in the soil.These results suggested that i)natural soil condition tended to create win-win situation for CH4 oxidation,and agricultural activities could disrupt the oxidation potentials of the soils;and ii)specific management practices including but not limiting to efficient fertilizer application and utilization,water use efciency,and less soil disruption might be required to increase the CH4 uptake from the soil.     

三峡库区耕地城镇化及城镇扩展测度

根据1975、1987、1995、2000和2005年的遥感影像解译出的城镇用地数据,分析了城镇扩展过程中耕地占用的规律,采用城镇用地扩展强度、城镇用地扩展极核、城镇用地扩展类型、城镇用地扩展紧凑度、城镇用地分维数等理论模型从数量上对研究区城镇用地的扩展进行了对比分析,然后采用缓冲区分析从空间上对研究区在不同缓冲区带内的扩展轨迹开展了对比分析。研究结果表明耕地占用较多的是重庆市区、渝北区;受重庆市区和渝北区生长极核的影响,邻近区县的扩展强度比较大;总的来看其扩展平稳有序,属紧凑填充式;缓冲区分析对城镇扩展的轨迹研究是有效的,在研究区的第二缓冲带内的城镇扩展的强度是较大的。对研究区1975～2005年期间城镇用地对耕地占用情况及扩展的空间模式的分析,有利于控制未来城镇化对耕地的占用,把握城市化进程所处的阶段及预测城市的未来发展趋势。     

伊朗西部不同土地利用方式下钙质土壤疏水性研究

Soil wettability and water repellency, two important soil physical properties, play an important role in water retention and water conductivity in arid and semi-arid regions. To date, there is a lack of information on soil water repellency in calcareous soils of western lran. In this study, soil water repellency and its affecting factors were studied using 20 soil series collected from Hamadan Province~ western Iran. The effects of soil properties including organic carbon content （SOC）, total nitrogen （TN）, C：N ratio, texture, CaCO3 content, and both fungal and bacterial activities on water repellency were investigated using air-dried, oven-dried and heated soil samples. Water repellency index （WRI） was determined using the short-time sorptivity （water/ethanol） method. To distinguish the actual effects of SOC, a set of soil samples were heated at 300 ~C to remove SOC and then WRI was measured on the heated samples. Relative water repellency index （RWRI） was defined as the change of WRI due to heating relative to the oven-dry WRI value. Results of the WRI values showed that the soils were sub-critically water-repellent. Pasture soils had higher WRI values compared to tilled soils, resulting from high SOC and TN, and high activities of bacteria and fungi. It was observed that SOC, TN, fungal activity, and SOC：clay ratio had significant positive impacts on WRI. Strong positive correlations of RWRI with SOC, TN and fungal activity were also observed. Pedotransfer functions derived for predicting WRI showed that the WRI values had an increasing trend with the increases in fungal activity, salinity, alkalinity and fine clay content, but showed a decreasing trend with increasing bacterial activity.     

Water-drop stability of PVA-treated natural soil aggregates from different land uses

Soil erodibility is a function of land use as it affects the stability of soil aggregates. The use of soil conditioners like polyvinyl alcohol (PVA) may help in reducing the soil erodibility, but it is important to economize the use of PVA. A study was carried out to evaluate the interactive effects of land use and PVA concentration on the water-drop stability of natural soil aggregates collected from eroded, forest, agricultural and grass lands. The water-drop stability of these aggregates was monitored using single raindrop simulator. The water-drop stability was lowest in eroded soils, followed by soils from agriculture, forest and grass lands. The smaller aggregates were more stable than the bigger ones. The water-drop stability of aggregates of different sizes and from different lands increased with the application of polyvinyl alcohol (PVA). The mean water-drop stability increased with the application of PVA at the rate of 0.05% by 40% in 2–5 and 5–10 mm aggregates. Increasing the PVA concentration to 0.1 and 0.2% increased water-drop stability value by 71–73% and 87–88%, respectively. The PVA application at the rate of 0.1% could increase the water-drop stability of soils under eroded land equivalent to that of the untreated grassland soils.     

城乡建设用地挂钩中补充耕地质量等别确定方法

针对目前城乡建设用地增减挂钩工作补充耕地质量无法保证的现状,该文以农用地分等成果为基础,构建了“事先(专项规划环节)-事中(实施规划环节)-事后(归还环节)”3个环节的补充耕地等别评定程序;并针对“挂钩”不同环节中补充耕地的“状态”不同,构建补充耕地等别不同评定方法.诸如:在专项规划环节构建运用相邻地域法、最低限值法来“模拟”补充耕地的自然质量属性值,并计算相应自然质量等别,最后利用各等别面积权重值计算出全部拆旧地块补充耕地的自然质量综合等别的评定方法;在实施规划环节构建利用复垦方案中复垦工程标准,采用目标值法给拆旧地块补充耕地自然质量属性赋值,并计算相应的自然质量等别.最后利用构建的“挂钩”中补充耕地评定程序和方法,对沈北新区城乡建设用地增减挂钩项目进行实证分析,并取得了较好预期效果.     

闽北不同土地利用方式与不同降雨强度对水土流失的影响

运用径流小区法研究闽北不同土地利用方式与不同降雨强度对水土流失的影响.结果表明:1)不同土地利用方式年均径流量的大小顺序为裸露地＞柑橘园＞锥栗林＞杉木林,年均土壤流失量的大小顺序为裸露地＞锥栗林＞柑橘园＞杉木林;2)降雨强度对土壤流失量的影响高于对径流量的影响,不同土地利用方式的径流量及土壤流失量与各降雨强度指标呈显著性幂函数关系,但各指标的拟合相关程度不同;3)裸露地(对照)土壤流失量与I10的相关性最高,锥栗林的土壤流失量与Ⅰ30和Ⅰ60的相关性最好,柑橘园的土壤流失量与Ⅰ30的相关性最好,而杉木林的土壤流失量与降雨强度的相关性极弱;4)裸露地、锥栗林和柑橘园的径流量与Ⅰ60和Ⅰ30的相关性较好,杉木林的径流量与降雨强度的相关性极弱;5)各土地利用方式的径流量和土壤流失量与Ⅰave的相关性均很弱.     

Soil quality in a Mediterranean area of Southern Italy as related to different land use types

The impact of different land use types on soil quality was evaluated by measuring several soil properties that are sensitive to stress or disturbance and by using two synthetic approaches, i.e. a numerical quality index and multivariate analysis. A Minimum Data Set of soil indicators was selected including physical (texture, bulk density and water holding capacity), chemical (pH, cation exchange capacity, electrical conductivity, organic carbon, total and mineral nitrogen, available K, Ca, Mg, P contents and total Cd, Cr, Cu, Pb and Zn contents) and biological (microbial biomass, fungal mycelium, soil potential respiration and potentially mineralizable nitrogen) parameters. These parameters were assayed on soil samples collected with seasonal frequency (except for physical parameters, determined only in autumn) in an area of Southern Italy under different land use types (i.e. permanent crops, grazing lands, shrublands, coniferous and mixed forests). Moreover, for most of the land use types, a further distinction on the basis of topographic position (hill, middle-hill and plain) was carried out. Annual means of the data (except for texture) were used to calculate a soil quality index (SQI) and elaborated by multivariate analyses (Cluster Analysis and Principal Component Analysis, PCA) in order to distinguish among different soil quality classes. Data indicated a clear difference in soil quality among the studied areas: low soil quality (SQI < 0.55) in almost all permanent crops; intermediate soil quality (0.55 < SQI < 0.70) in shrublands, grazing lands, coniferous forest and middle-hill olive grove (the only crop with an herb layer on the soil surface); high soil quality (SQI > 0.70) in mixed forests. Results suggested that the permanent crop management had generally a strong negative impact on soil quality, while the moderate grazing activity and the crop management that leaves an herb cover on the soil had a lower negative impact. Nevertheless, the abandonment of cultivated lands, with consequent development of shrublands, produced an improvement of soil quality suggesting a good recovery capacity in the studied soil.     

The number and biomass of microorganisms in ancient buried and recent chernozems under different land uses

The size, number, and biomass of bacteria and microscopic fungi were studied in chernozems of different land uses (forest, fallow, pasture, and cropland), in paleosols under mounds of different ages in the territories adjacent to the background recent chernozems; and in the cultural layer of an ancient settlement of the Bronze Age, Early Iron Age, and Early Middle Age (4100–1050 years ago). The method of cascade filtration revealed that bacterial cells had a diameter from 0.1 to 1.85 μm; their average volume varied from 0.2 to 1.1 μm³. Large bacterial cells predominated in the soils of natural biocenoses; fine cells were dominants in the arable soils and their ancient analogues. The bacterial biomass counted by the method of cascade filtration was first found to be 10–380 times greater than that determined by luminescence microscopy. The maximal bacterial biomass (350–700 μg/g) was found in the soils of the birch forest edge (~80-year-old) and under the 80-year-old fallow. In the soils of the 15–20 year-old fallows and pastures, the bacterial biomass was 110–180 μg/g; in the arable soils and soils under the mounds, it was 80–130 and 30–130 μg/g, respectively. The same sequence was recorded in soils for the content of fungal mycelium and spores, which predominated over the bacterial mass. With the increasing age of the buried paleosols from 1100 to 3900 years, the share of the biomass of fungal spores increased in the total fungal and total microbial biomasses. In the cultural layer of the Berezovaya Luka (Altai region) settlement that had been functioning about 4000 years ago, the maximal biomass and number of fungal spores and the average biomass of bacteria and fungal mycelium comparable to that in the studied soils were revealed. In this cultural layer, the organic matter content was low (Corg, 0.4%), and the content of available phosphorus was high (P₂O₅, 17 mg/g). These facts attest to the significant saturation of this layer with microbial cenoses 4000 years ago and to their partial preservation up to now owing to the high concentration of ancient human wastes there.     

黄土区不同土地利用方式坡面土壤含水率的空间变异性研究

为掌握不同土地利用方式下坡面土壤含水率的空间分布特征及其变异规律，利用经典统计学方法对黄土高原水蚀风蚀交错带草地和农地坡面土壤含水率的空间变异性进行了对比研究。结果表明：草地和农地的土壤含水率均值在同一土层深度下差异极显著，但二者在垂直方向、坡长方向的变异程度均为中等变异程度；草地和农地坡面土壤含水率的垂直变化特征不同，前者为降低型，后者在100 cm以上为波动型，以下为稳定型；草地和农地坡面土壤含水率均随坡长的增加呈波浪式变化规律，整体上有增加趋势；将坡面划分为5个坡长或将土层划分为4层以后，草地和农地坡面土壤含水率沿垂直方向、坡长方向的总体变化趋势均没有改变，但由于尺度的扩展获得了一些较大尺度上的水分信息。