首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 201 毫秒
1.
土壤水分是黄土高原水蚀风蚀交错带生态环境恢复的关键因子,具有明显的时空异质性。以水蚀风蚀交错带的代表性流域—老爷满渠小流域为对象,采用网格法(50 m×50 m)共布设了73个样点,原位观测0—5 m土壤含水率,共测定23次(2013年6月至2019年10月),通过获取每个样点的环境因子,结合经典统计、地统计、随机森林等方法,分析了小流域尺度不同土层深度(每层1 m,共5层)土壤含水率的季节变化特征与影响因素。结果表明:不同土层土壤含水率的空间分布特征和季节性变化规律不同;对于0—1 m土层,土壤含水率在夏季和冬季之间存在显著性差异(p0.05),而对于1 m以下土层,春季平均土壤含水率高于其他季节,但不显著;无论在何种季节,不同土地利用方式、壤土与砂土间的土壤含水率在3 m以上土层均存在显著差异(p0.05),而阴、阳坡的土壤含水率在所有土层均存在显著差异(p0.05);在不同季节,土壤含水率与容重和砂粒呈负相关,与其他环境因子(有机碳含量、黏粒、粉粒、有机碳密度、土地利用、坡向、土壤质地和pH)呈正相关;除有机碳密度和黏粒较为稳定外,土壤含水率与环境因子的相关性均随土层深度增加呈减少趋势;环境因子对土壤含水率空间变异的整体相对贡献表现为土壤性质地形土地利用。研究结果可为研究区深层土壤水资源管理、土壤水文观测与模拟、植被优化布局等提供参考。  相似文献   

2.
长武王东沟小流域土壤墒情影响因素与分布特征   总被引:9,自引:1,他引:8  
黄土高原一个小流域内,因坡向、坡度和小地形的明显地貌分异,导致土壤墒情分布的差异,进而影响土地生产力。本文通过不同地类、不同利用下35个测点实测资料,就小流域土壤水分性质、土壤墒情分类、墒情与地类的关系,影响墒情优劣的因素、林网墒情效应等方面阐述了小流域内土壤墒情分异的某些规律性。  相似文献   

3.
研究土地复垦类型及微地形对土壤养分的影响对于指导土地复垦实践,控制复垦土地水土流失等具有重要的理论意义和实际应用价值。以平朔露天煤矿排土场为例,借助数理统计方法分析评价复垦类型与微地形因子(高程、坡度、坡向)对土壤有机碳、全氮、全磷、有效磷及速效钾含量的影响。结果表明:(1)复垦类型对各项土壤养分含量影响较为显著,不同的复垦类型中,各项土壤养分含量排序均为耕地林地草地;其中,土壤有机碳、全氮、全磷及速效钾含量,耕地分别为草地的2.15~2.68倍,林地的1.48~1.78倍,对于土壤有效磷,耕地中的含量为71.24mg/kg,为草地的11倍,林地的4倍;(2)坡度与土壤养分含量之间存在显著的相关性(p0.05),而高程、坡向与土壤养分含量的相关性较弱,表明排土场复垦区土壤养分受坡度影响较大,而受高程与坡向的影响较小;(3)复垦类型与坡度的交互作用对土壤养分含量产生一定的影响:同一复垦类型的不同坡度的土地养分含量存在差异,耕地的土壤养分含量随着坡度的增大在降低;同一坡度,不同的复垦类型条件下,土壤养分差异显著,总体趋势为耕地林地草地。  相似文献   

4.
基于地理探测器的宝鸡市农田土壤养分影响因子分析   总被引:1,自引:0,他引:1  
《土壤通报》2020,(1):71-78
为分析陕西省宝鸡市农田土壤养分空间变异情况及其影响因素,选取土地利用类型、成土母质、土壤类型、高程、坡度、坡向、年均降水量、年均气温8种影响因子,借助地理探测器分析各因子对土壤有机质(SOM)、有效磷(AP)、速效钾(AK)、全氮(TN)养分空间变异的影响。结果表明:造成SOM空间变异主要三因子分别为土地利用方式、土壤类型、年均气温;AP与AK的主要影响因子为成土母质、高程、土地利用方式;对TN解释力较大的三因子为土地利用方式、土壤类型、成土母质。即各因子对土壤养分空间变异原因的解释力存在一定的差异,气温变化对TN和SOM影响较大,高程是对4种土壤养分解释力较强的地形因子。交互探测器探测结果表明:两因子间的交互作用对养分的解释力均强于单因子,地形因子与其他因子交互之后解释力显著增强。影响因子与养分之间主要作用方式为双协同作用和非线性协同作用。随着高程的变化,4种养分含量呈现不同的变化趋势。此外,通过与Pearson相关系数法分析结果进行对比,发现地理探测器可以得到与之一致的因子重要性排序,适用于该区域土壤养分的研究。  相似文献   

5.
研究土壤属性空间变异及其分布特征与环境因子的关系,对于了解生态系统的过程具有重要意义。以横山县为例,采集了254个耕层(0~20 cm)土样,利用数字地形与遥感影像分析技术,提取相关地形与遥感指数,分析不同土地利用、地形条件下土壤养分空间变异及分布特征,并结合回归分析与地统计学进行空间分布预测。结果表明,不同土地利用类型其养分含量差异显著,水田和川地的有机质和全氮含量明显高于其他土地利用类型,而全磷含量以梯田最高。不同坡度分析表明,"0~3°"坡度等级有机质和全氮含量显著高于其他坡度等级;不同坡向土壤养分含量差异均不显著,但存在一个明显的趋势,即阴坡有机质和全氮含量整体上要较阳坡高。土壤有机质与高程H呈现负相关,与坡向的余弦值cosα、复合地形指数CTI、修正后的土壤调节植被指数MSAVI及湿度指数WI呈正相关。土壤全氮与相关环境因子的关系基本与有机质的一致。而土壤全磷与修正后的土壤调节植被指数MSAVI及湿度指数WI正相关。土壤有机质和全氮用相关环境变量的多元线性逐步回归模型拟合预测较好,而对于全磷,预测结果较差;回归—克里格预测有效地减小了残差,消除了平滑效应,与实测值较为接近,预测精度高于多元线性逐步回归预测。  相似文献   

6.
[目的]分析朱溪流域土壤容重与地形和土地利用之间的关系,为南方红壤侵蚀区水土保持提供相关理论依据。[方法]以福建省长汀县朱溪流域为基础,基于GIS和地统计分析原理,并结合经典统计学方法分析土壤容重的空间变异性。采用拟合度最好的球状模型拟合土壤容重的半变异函数,并采用普通Kriging空间插值法,对研究区土壤容重空间分布进行预测。在此基础上利用ArcGIS空间分析功能统计高程和坡度各分区内的土壤容重均值,并利用栅格叠加分析,分析不同土地利用下土壤容重分布情况。[结果](1)朱溪小流域土壤容重具有从东北向西南增大的趋势,容重低值区主要分布在东部和东北部,高值区主要分布在西南部和中部。(2)流域土壤容重具有随海拔和坡度增大而降低的趋势,坡位和坡向则对该地区土壤容重空间分布影响不明显。(3)居民点及工矿用地和交通用地土壤容重均值明显大于林地、草地等植被盖度较好的区域。[结论]地形和土地利用是影响朱溪小流域土壤容重的重要因子,而高程和坡度是主要地形影响因子;不同土地利用类型土壤容重差异显著,植被覆盖好的区域土壤容重显著低于其他土地类型,因此应加强植被保护,以改善土壤结构。  相似文献   

7.
黄土丘陵沟壑区小流域土壤水分空间变异性及其影响因素   总被引:1,自引:0,他引:1  
为了解不同土地利用方式和地形条件下土壤含水率的数量特征及其变异规律,以黄土高原丘陵沟壑区纸坊沟小流域为研究对象,利用经典统计学方法系统分析了小流域尺度土壤含水率的空间变异性。结果表明:不同土地利用方式下土壤平均含水率之间呈极显著差异,其顺序为:农田>草地>林地>灌木地;土壤含水率在土壤剖面上呈先减小后增大的趋势。地形条件显著影响土壤含水率,其中梯田>沟底>坡地>峁顶;不同坡位土壤含水率的顺序为坡下>坡上>坡中,不同坡向间为阴坡>阳坡。上述土壤含水量的变异程度均为中等。在小流域尺度,土地利用和地形对土壤水分具有显著的交互作用。相关结果可为黄土丘陵沟壑区的土壤水分管理、土地利用结构优化、不同地形条件下的植被布局提供参考。  相似文献   

8.
地形对漫川漫岗黑土区大豆产量的影响   总被引:2,自引:2,他引:0  
为研究黑土区田块尺度地形对大豆产量造成的影响,在海伦东兴合作社具有明显地形起伏的地块,采集大豆田间试验数据,考虑温度、太阳辐射、坡度、土壤养分等因素,运用作物生长模型DSSAT(Decision Support Systemfor Agrotechnology Transfer)模型对各样点进行参数率定及验证,得出以下结论:1)DSSAT模型的模拟产量与实际产量的相对均方根误差为7.9%,模拟结果表现为优,表明运用作物模型模拟不同地形上的产量变异具有可行性;2)地形通过影响作物生长环境因子的时空差异决定产量差异,田块尺度温度、水分和坡度是影响产量差异的主要因素;3)坡顶和坡底的产量相对较高,且产量变异性较小,阳坡虽然接收到更多的光照,却由于水分胁迫造成减产,坡底和平缓坡顶水肥保持较好,易获得高产。研究成果为田间精细管理与田块尺度耕地高效利用提供科学依据。  相似文献   

9.
为探明小流域土壤养分特性空间变异规律及其与环境因子的关系,以非均匀取样方法测定了黄土高原水蚀风蚀交错带小流域土壤表层(0~10、10~20、20~40 cm)的硝态氮和铵态氮,采用经典统计和地统计学方法分析了其空间分布特征及变异结构。结果表明:土地利用空间配置成混合利用结构拦截和减少径流侵蚀,形成了土壤矿质氮坡面斑块镶嵌格局。小流域内硝态氮和铵态氮呈中等的空间变异和自相关性,其变异性由土壤系统内部因素包括土壤质地、矿物、成土过程、地形特征和人类活动造成的外部因素包括施肥和耕作等共同控制。建立了土壤矿质氮多元回归预测模型,各回归模型的自变量不同,表明不同土层硝态氮和铵态氮的变异受不同环境因子控制。分析认为合理配置土地利用形成斑块状结构和增加养分投入可以改善研究区土壤质量。  相似文献   

10.
为探讨坡耕地土壤退化程度及其与坡度的关系,在沂蒙山区选择典型小流域,通过测定流域内不同坡度坡耕地、弃耕地与生态林地的土壤颗粒组成、分形维数、土壤养分质量分数的变化及其相关性,研究坡耕地土壤颗粒结构与养分退化特征。结果表明:1)所有土地利用类型,土壤砂粒体积分数最高,黏粒体积分数最低,平均值分别为70.81%、0.75%;2)土壤颗粒分形维数、有机质质量分数为生态林地〉弃耕地〉坡耕地;3)坡耕地土壤颗粒分形维数随坡度增加而减小,其大小与土壤粉粒和黏粒体积分数分别呈极显著、显著正相关;4)所有土地利用类型,土壤有机质质量分数与砂粒体积分数显著负相关,与粉粒和黏粒体积分数显著正相关,土壤氮、磷、钾养分质量分数与土壤颗粒体积分数相关性不显著;5)研究区土壤具有粗骨性砂土的物理特性,坡耕地耕作或坡度加大会增强土壤粉粒和黏粒的流失,导致土壤颗粒分布的均匀性及其分维数下降,水肥保蓄性能和养分质量分数降低。  相似文献   

11.
As a result of human disturbance and topographic variability, land use mosaics are characteristic of the transition zone of the Loess Plateau in Shaanxi Province, China. Soils are particularly sensitive to change when land degradation processes are dominant. An understanding of the influences of environmental variables is required to inform land management and agricultural production. In this study the relationships between land type, topography and soil properties were analysed for Hengshan County at two different scales using detrended canonical correspondence analysis. The results show that variations in soil properties are strongly influenced by topography, land use and vegetation. Slope, elevation and aspect are also of importance at the county and small catchment scales of analysis. Though land use type proved to be of lesser importance than topographic factors, ANOVA analysis showed that there were significant differences in soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), available nitrogen, available potassium and clay %. Areas under vegetables had significantly higher SOM and TN content at the catchment scale. The results will enhance our ability to predict spatial and temporal changes in soils. In addition, it is shown that soil fertility could be improved by land reform and management in the hilly‐gully area.  相似文献   

12.
Intensive land use practices necessary for providing food and raw materials are known to have a deleterious effect on soil. However, the effects that such practices have on soil microbes are less well understood. To investigate the effects of land use intensification on soil microbial communities we used a combined T-RFLP and pyrosequencing approach to study bacteria, archaea and fungi in spring and autumn at five long term observatories (LTOs) in Europe; each with a particular land use type and contrasting levels of intensification (low and high). Generally, due to large gradients in soil variables, both molecular methods revealed that soil microbial communities were structured according to differences in soil conditions between the LTOs, more so than land use intensity. Moreover, variance partitioning analysis also showed that soil properties better explained the differences in microbial communities than land use intensity effects. Predictable responses in dominant bacterial, archaeal and fungal taxa to edaphic conditions (e.g. soil pH and resource availability) were apparent between the LTOs. Some effects of land use intensification at individual field sites were observed. However, these effects were manifest when land use change affected soil conditions. Uniquely, this study details the responses of different microbial groups to soil type and land use intensification, and their relative importance across a range of European field sites. These findings reinforce our understanding of drivers impacting soil microbial community structure at both field and larger geographic scales.  相似文献   

13.
亚热带红壤丘陵区典型景观单元土壤养分的空间变异   总被引:3,自引:0,他引:3  
基于区域化变量理论和地理信息系统的空间分析功能,应用地统计学的半变异函数定量分析了亚热带红壤丘陵区典型景观单元土壤养分的空间异质性特征。结果表明,土壤有机碳和全磷的理论模型为球状模型、全氮为高斯模型、土壤pH为指数模型。在60m步长间隔尺度下,土壤有机碳、全氮和pH有强烈的空间相关性,土壤全磷空间相关性为中等程度。4种土壤养分的空间自相关范围具有明显的差异,有机碳的有效变程最大(为261m),全氮(208m)和pH(156m)次之,全磷的有效变程最小(133m)。其空间自相关范围的差异由本身的养分、土地利用格局、地形和人为管理措施等因素所决定。在GIS支持下,采用Kriging插值方法,分析景观单元内土壤养分的空间分布格局看出,土壤有机碳和全氮含量呈现出明显的条带状和斑块状的梯度变化,并表现出极为相似的空间分布格局;土壤全磷的空间分布随机性强,斑块变得更加琐碎并呈现镶嵌的星空状分布;土壤pH的空间分布格局处于其三者之间,没有表现出明显的条带状分布。总体上说,基于整个景观尺度的4种土壤养分的半方差拟合效果优于不同土地利用类型的拟合效果。  相似文献   

14.
This paper shows how the wavelet transform can be used to analyse the complex spatial covariation of the rate of nitrous oxide (N2O) emissions from the soil with soil properties that are expected to control the evolution of N2O. We use data on N2O emission rates from soil cores collected at 4‐m intervals on a 1024‐m transect across arable land at Silsoe in England. Various soil properties, particularly those expected to influence N2O production in the soil, were also determined on these cores. We used the adapted maximal overlap discrete wavelet transform (AMODWT) coefficients for the N2O emissions and soil variables to compute their wavelet covariances and correlations. These showed that, over the transect as a whole, some soil properties were significantly correlated with N2O emissions at fine spatial scales (soil carbon content), others at intermediate scales (soil water content) and others at coarse spatial scales (soil pH). Ammonium did not appear to be correlated with N2O emissions at any scale, suggesting that nitrification was not a significant source of N2O from these soils in the conditions that pertained at sampling. We used a procedure to detect changes in the wavelet correlations at several spatial scales. This showed that certain soil properties were correlated with N2O emissions only under certain conditions of topography or parent material. This is not unexpected given that N2O is generated by biological processes in the soil, so the rate of emission may be subject to one limiting factor in one environment and a different factor elsewhere. Such changes in the relationship between variables from one part of the landscape to another is not consistent with the geostatistical assumption that our data are realizations of coregionalized random variables.  相似文献   

15.
Many soil properties and processes vary at different spatial scales. As a result, relationships between soil properties often depend on scale. In this paper we show this for two soil properties of biological importance, by means of a nested analysis of covariance. The variables were urease activity (UA) and soil organic carbon (SOC), sampled on an unbalanced nested design at three sites with different land uses (arable, forest and pasture). The objective of this study was to investigate the scale‐dependent relationships of UA and SOC at these three sites to exemplify the phenomenon of scale‐dependency in the covariation of biogeochemical variables. At each site the variables showed different scale dependencies, expressed in their correlations at different scales. At the pasture site, UA and SOC were uncorrelated at all scales in the sampling design (0.2 m, 1 m, 6 m and ≥15 m), and the overall product moment correlation was 0.10. A significant positive scale dependent correlation (0.65) was found at the 1‐m scale for the forested site. The soil properties were not spatially correlated at any of the other scales and the associated product moment correlation for this site was 0.14. Urease activity and soil organic C were found not to be correlated at the shorter scales in the arable site. However, significant positive correlation coefficients of 0.89 and 0.82 were obtained at the longer scales of 6 and ≥15‐m respectively for the arable site. The product moment correlation at this site was 0.65. At both the arable and forest site, we found that correlations at particular scales were stronger than the overall product moment correlation. This approach allowed us to identify significant relationships between urease activity and soil organic carbon and the scales at which these relationships occur and to draw conclusions about the spatial scales, which must be resolved in further studies of these variables in these contrasting environments. This study highlights the pervasive effect of scale in soil biogeochemistry and shows that scale‐dependence must not be disregarded by soil scientists in their investigations of biogeochemical processes.  相似文献   

16.
土壤侵蚀时空变异及其与环境因子的时空关系   总被引:52,自引:7,他引:45  
土壤侵蚀的时空变异是指在一定的景观内 ,不同时间、不同地点的土地侵蚀特征存在明显的差异性和多样性。土壤侵蚀的时空变异是多重尺度上的植被、土地利用、气象 (降雨 )、地形和土壤等多因子综合作用的结果 ,但是就某一具体地区而言存在重点尺度和主控因子 ,土壤侵蚀的重点尺度与主控因子的时空关系因时间、空间和尺度而异。综述了土壤侵蚀的时空变异及其与环境因子时空关系的研究进展  相似文献   

17.
Spatial variability presents a challenge for effective measurement of ecological processes in soil ecosystems. This study characterized the heterogeneity of seven different biotic and abiotic soil properties at three ecological scales: land‐use type (vegetation type), site (scale of km to tens of km, and subplot (10–30 m). We addressed three questions about soil properties: (i) Do they differ more at any ecological scale when compared with other scales? (ii) Does physically combining samples from replicate subplots affect their measurement? (iii) What are the implications of this variation for the detection of differences caused by changing land‐use? There were five land‐use types: remnant rainforest, pasture, ecological restoration plantings 10–15 yrs old, 40–50 yrs regrowth dominated by the non‐native tree camphor laurel (Cinnamomum camphora) and rainforest regrowth 3–6 yrs after poisoning of camphor trees within older regrowth. Sites were interspersed within a 750 km2 region of subtropical Eastern Australia. In general, variability was greatest at the site and subplot levels. Soil water content, soil organic matter and pH were less variable than total organic carbon, microbial biomass, nitrate and nitrification. Power analyses using total organic carbon and nitrate showed that adequate replication at both site and subplot levels was important for detecting effects of land‐use type, although increased replication was slightly more effective for subplots than for sites. Subplot spacing was relatively unimportant. Physically combining subplot samples to yield one aggregate measurement per site was successful in reducing analytical effort without sacrificing accuracy for all soil properties except total organic carbon and nitrification.  相似文献   

18.
神府东胜煤田复垦区土壤入渗特性的试验研究   总被引:2,自引:0,他引:2  
土壤入渗性能是最基本的土壤物理特性之一。复垦区土壤的结构组成复杂,入渗特性有别于非矿区土壤。本文以神府东胜煤田马家塔复垦区为研究对象,利用圆盘入渗仪分别测定了复垦区乔木、林地、荒地、灌木林地和草地的土壤入渗特性,用经典统计学方法对复垦区土壤入渗性能的空间变异性进行了分析。实测结果表明,不同土地利用方式下的土壤入渗特性有较大的差异;在测定范围内,乔木林地、荒地、草地和灌木林地的稳定入渗率均表现出0 cm>—3 cm>—15 cm的规律性,其中草地稳定入渗率随吸力的变化更明显。研究表明:乔木林地稳定入渗率和累积入渗量的变异系数分别为0.58和0.49.属于中等变异。  相似文献   

19.
Conventional classification systems based on vegetation and land use are frequently used to characterize or describe urban soils to determine the influence of urbanization on soils. In this study, the sensitivity of different grouping methods in reflecting soil variations along an urban–rural gradient was compared. The objective of this study was to determine the most sensitive grouping system in depicting and explaining variations of soil attributes around an urban area. Grouping methods, including urban–rural division, in situ vegetation type, land use types in different scales and numerical clustering, were compared for both single soil attributes and “soil set” defined by multiple variables. The result shows urbanization has a strong impact on many soil properties, especially that of gravel content, sand content, pH, phosphorus and soil compaction. In terms of the variations of soil attributes, in situ vegetation type is the most sensitive in comparison with local land use types and district-viewed land use types. In other words, soil properties in this study are not sensitive to coarser spatial resolution. Therefore, it's hard to interpret the spatial variation of urban soil by regular methods using natural soil-landscape paradigm. Furthermore, vegetation would best proxy the delineation of single attribute of urban soils. Numerical clusters effectively reflect the land use types and their change during urbanization. All clusters were interpreted as different sets with practical meanings: soil in abandoned greenbelt, soil in ill-managed greenbelt, soil in new vegetable land, extreme urban conditioned soil, soil in well-managed greenbelt, soil in highly mellowed vegetable land, soil in common urban–peri-urban greenbelt and weak-urban-impacted soil. They can be used as bases for soil regionalization in urban and peri-urban environment.  相似文献   

20.
Soil properties can vary spatially due to differences in topography, parent material, and land management practices. For site-specific management within the field, information on spatial variation of soil properties is essential. This case study was conducted to quantify the spatial variability of available plant nutrients and organic matter under arable cropping in New Zealand. Within a 10.4-ha paddock that had a long-term history of arable cropping, 91 samples (0–7.5 cm) were collected in a grid pattern for determination of mineral nitrogen (Min N), anaerobically mineralizable N (AMN), Olsen P, total carbon (TC), and total N (TN). The data were evaluated using geostatistical and classical statistical methods. Although the paddock had a flat topography and had been managed uniformly for many years, nutrient concentrations exhibited substantial variability. All measured variables except mineral N showed moderate positional dependence. Autocorrelation distances were 400 m for Olsen P, 293 m for AMN, and 347 m for TC. Soil C showed a strong, positive correlation with the amount of clay plus fine silt (<5 µm fraction) and a negative correlation with sand content. These results suggest that textural variation was a major factor influencing within-field variability in soil organic matter. Using the spatial data, zones with different plant nutrient requirements were identified (four for N; two for P). An application strategy that accounts for fertility differences between zones may improve fertilizer use efficiency and contribute to better environmental outcomes; P inputs could be reduced by 50% by avoiding application to the high Olsen P zone.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号