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1.
土壤饱和导水率（Ks）是反映土壤入渗性能与土壤持水能力的重要参数，为探究流域尺度下土壤Ks的空间分布特征及影响因素，更好地掌握土壤水文过程与调节机理，选取晋西北黄土丘陵区朱家川流域横向梯度（上游、中游、下游）不同土地利用方式下的土壤（70个样点）为研究对象，采用定水头法测定土壤Ks，并获取样点地形因子和其他土壤理化性质，通过建立土壤Ks偏最小二乘回归模型（PLSR），分析影响土壤Ks空间分布格局的主要因素。结果表明：（1）除土壤容重和砂粒含量为弱变异外，区域土壤理化性质其余因子均为中等变异；土壤Ks在横向梯度下表现为上游 > 中游 > 下游；（2）不同土地利用方式下土壤Ks差异显著（P<0.05），由高到低顺序为林地 > 农地 > 草地；（3）林地（VIP=1.997）与草地（VIP=1.710）利用方式、土壤容重（VIP=1.548）、土壤有机质（VIP=1.323）、大团聚体（VIP=1.266）、粉粒含量（VIP=1.062）和黏粒含量（VIP=1.049）是土壤Ks变化的主要因素，林地利用方式影响程度最大。土地利用、土壤性质、地形因子均是影响黄土丘陵区土壤Ks空间分布的主要因素，是用来模拟预测土壤Ks空间分布的重要因子。 相似文献
2.
Sensitivity analysis is important for determining the parameters in the model calibration process. In our study, a variance-based global sensitivity analysis (extended Fourier amplitude sensitivity test, EFAST) was applied to an agro-hydrological model (the SWAP (Soil-Water-Atmosphere-Plant model) model). The sensitivities of 20 parameters belonging to 4 categories (soil hydraulics, solute transport, root water uptake, and environmental stresses) for the simulated accumulated transpiration, dry matter (DM), and yield of sunflowers were analyzed under three nitrogen application rates (N1, N2, and N3), four salinity levels (S1, S2, S3, and S4), and three root distributions (R1, R2, and R3). The results indicated that for predominantly loamy soils, the high-impact parameters for accumulated transpiration, DM, and yield were the soil hydraulic parameters (α and n), critical stress index for compensatory root water uptake (ωc), the salt level at which salt stress starts (Pi), the decline of root water uptake above Pi (SSF), residual water content (θr), saturated water content (θs), and relative uptake of solutes by roots (TSCF). We also found that nitrogen application did not change the order of the parameter impacts on accumulated transpiration, DM, and yield. However, TSCF replaced α as the highest-impact parameter for the accumulated transpiration, DM, and yield at high salinity levels (S2 and S3). Furthermore, α was also the highest-impact parameter for DM and yield under different root distributions, but the highest-impact parameters for transpiration were ωc, α, and θs under R1, R2, and R3, respectively. Nitrogen application could be neglected when considering the interactive effects of nitrogen application, salinity level, and root distribution on the transpiration, DM, and yield. Additionally, the mean values and uncertainties of the transpiration, DM, and yield were similar in all scenarios, except S3, which showed a sharp decrease in the mean values. We suggest determining the above eight parameters (α, n, ωc, Pi, SSF, θr, θs, and TSCF) and the saturated vertical hydraulic conductivity (Ks) based on rigorous calibrations with direct or indirect local measurements using economical methods (e.g., a literature review), with limited observations for other parameters when using the SWAP model and other similar agro-hydrological models. 相似文献
3.
[目的] 探究晋陕蒙地区土壤质地重构对土壤水力性质的影响,评价砒砂岩不同添加量对砂黄土的改良效果,为该区沙化土地修复工作提供理论依据。[方法] 将砒砂岩与砂黄土按照不同配比进行重构,研究其饱和导水率、土壤水分特征曲线、土壤有效持水量等指标。[结果] ①随着砒砂岩比例的增加(0%～100%),重构土中砂粒(0.05～2 mm)含量下降8.1%～33.5%,粉粒(0.002～0.05 mm)和黏粒(＜0.002 mm)含量分别增加5.2%～21.0%,2.9%～12.5%。当砒砂岩与砂黄土比例达到75∶25时,重构土壤质地由砂壤土转变为壤土;当砒砂岩与砂黄土按照25∶75比例混合时,该处理在10 ℃时的Ks为4.07×10-6 m/s,与黄土高原地区典型的黄绵土田间自然状态下的Ks值相近; ②砒砂岩添加量对土壤水分特征曲线的影响主要在高吸力段,当砒砂岩与砂黄土的比例为25∶75时,土壤水分有效性相对较高; ③随着砒砂岩含量增加土壤保水性能呈现上升趋势,砒砂岩的添加比例越高,重构土壤饱和含水量(θs)和残余含水量(θr)越大。[结论] 砒砂岩与砂黄土按25∶75比例重构(土壤容重1.41 g/cm3)土壤有效持水量显著高于其他处理,是晋陕蒙地区土壤改良的有效方法。 相似文献
4.
保护性耕作对太行山前平原土壤质量的影响 总被引：7，自引：2，他引：5
保护性耕作被认为是华北平原农业可持续发展的重要措施, 但目前缺乏这些措施对土壤质量影响的系统报道。本研究以长期定位试验为基础, 探讨了太行山前平原两熟制高产农田不同耕作措施对麦田土壤质量的影响。试验始于2001 年, 设置翻耕玉米秸秆不还田(非保护性耕作对照, CK)、翻耕玉米秸秆粉碎还田(CT)、旋耕玉米秸秆粉碎还田(RT)和免耕玉米秸秆直立还田(NT)4 个处理。2007 年冬小麦收获后分层测定土壤有机碳(soil organic carbon, SOC)含量、容重(ρb)、水稳性团聚体、水分特征曲线、饱和导水率(Ks)和微生物量碳氮。2008 年测定了剖面SOC 含量、ρb 和蚯蚓数量。结果表明, 连续多年保护性耕作后土壤剖面的SOC 储量无显著变化, 但保护性耕作(RT 和NT)下SOC 的层化比率(1.74~2.04)显著高于翻耕处理(CK 和CT, 1.37~1.45); 保护性耕作显著提高了表层微生物量碳、氮含量以及单位面积土壤中的蚯蚓数量。NT 处理导致耕层(0~20 cm)土壤ρb 增加, 但提高了土壤团聚体的稳定性。CK 和CT 处理显著增加了0~5 cm 土层裂隙(>500 μm)和传输孔隙(500~50 μm)的比例, 而NT 处理则增加储水孔隙(50~0.5 μm)的含量。另外, 保护性耕作提高了土壤的Ks、田间持水量和有效水含量。对土壤质量指标S 的分析结果表明, 实施保护性耕作后, 太行山前平原地区土壤质量总体上得到改善。 相似文献
5.
研究典型植被类型的土壤饱和导水率(Ks)分布及其影响因素,可为北京山区植被建设提供有力借鉴,同时加深对于土壤水分运动的理解。选取北京山区最具代表性的4种植被类型,获取不同类型、不同层次的土壤饱和导水率,调查土壤理化性质与根系生物量、石砾体积,利用Pearson相关性分析、多元逐步回归、通径分析,明晰了北京山区典型植被类型下的土壤饱和导水率分布及其影响因素。结果表明:(1)土壤饱和导水率介于0.05~2.23 mm/min,属于高度变异,随土层向下不断减小,侧柏×灌木混交林、侧柏纯林与侧柏×五角枫混交林的土壤饱和导水率存在显著差异(p＜0.05)。土壤饱和导水率与土层深度之间的关系符合对数函数关系式y=±aln x+b,R2≥0.858。(2)相关性分析结果表明,土壤饱和导水率与容重、总孔隙度、毛管孔隙度、根系生物量、有机质含量均呈极显著相关关系(p＜0.01),与非毛管孔隙度、自然含水率呈显著相关关系(p＜0.05)。(3)逐步回归分析得Y=3.42X2+0.78X6-1.333,R2=0.862。进一步通径分析可知,根系生物量主要通过直接作用影响土壤饱和导水率,而总孔隙度通过间接作用影响土壤饱和导水率。可知,侧柏×灌木混交林的导水性能最佳,后续的植被建设应重点考虑侧柏×灌木混交林,以达到减少径流、涵养水源的目的。 相似文献
6.
甜高粱茎秆汁液固定化酵母酒精发酵的研究 总被引：28，自引：8，他引：20
本文应用一元线性回归分析法得出了甜高粱茎秆汁液锤度和可溶性总糖含量之间的关系。以甜高粱茎秆汁液为原料,在摇床及流化床反应器上进行了固定化酵母酒精发酵的试验研究。结果表明,以沈农甜杂2号甜高粱为原料,在摇床上作营养盐配比的正交试验,试验得出对提高酒精得率影响因素的主次顺序为：(NH4)2SO4,K2HPO4,MgSO4。最优组合为：0.125% K2HPO4,0.200%(NH4)2SO4,0.050% MgSO4。加营养盐的酒精得率比不加任何营养盐的酒精得率可提高4.0%～8.0%。K2HPO4,(NH4)2SO4的配比对试验结果影响极显著,MgSO4的配比对试验结果影响显著。在流化床反应器上试验,4种较优营养盐组合酒精得率近乎相等,比不加营养盐空白试验酒精得率高。从降低成本角度来讲,选择0.125% K2HPO4,0.200%(NH4)2SO4,0.010% MgSO4作为投产试验。本文为燃料乙醇的发展提供了科学的依据。 相似文献
7.
农田土壤养分的空间变异性特征 总被引：169，自引：18，他引：151
对一块面积为１ｈｍ２麦田内的９８个观测点取样分析,测定了代表不同土壤含水率水平下的两个时期土壤表层和底层的ＮＨ４-Ｎ、ＮＯ3-Ｎ、Ｏｌｓｅｎ-Ｐ、表层有机质和全氮等养分。应用地统计学的方法对所取的数据进行了分析,结果表明底层土壤的ＮＨ４-Ｎ、表层土壤的有机质服从正态分布;其余养分基本上服从对数正态分布;按一定的精度和置信水平确定了合理的取样数目。通过半方差函数分析,发现这些养分在一定范围内存在空间相关性;采用Ｋｒｉｇｉｎｇ方法对未测点进行了估值,绘制了等值线图,并对两个时期的养分动态的空间变异进行了初步分析。该成果可用于提高氮肥利用率和精确农业（施肥）的研究和实践。 相似文献
8.
通过人工控制水分,形成单株幼龄侧柏的不同土壤水分梯度环境。在自然环境下对侧柏叶片定时、定位进行蒸腾速率及林冠层的光照、空气温度、空气湿度、叶水势和土壤水分等因子的同步观测。蒸腾速率与各个因子的相关分析表明:黄土半干旱地区侧柏蒸腾速率ηt/(μg·cm-2·s-1)与光照强度E/(μmol·m-2·s-1)、空气饱和差pv/kPa、叶水势Ψ/kPa、气温t/℃的关系可以分别表示为:ηt=>αEb,ηt=αpvb,ηt=αψb,ηt=αt2+bt+c;侧柏的蒸腾速率ηt与气孔阻力Rs/(s·cm-1)和土壤含水量W/％有密切关系,可以分别表示为:ηt=α+bW+cW2+dW3,Rs=α+bW+cW2+dW3。用气温、空气饱和差、叶水势3个因素建立了半干旱黄土地区幼龄单株侧柏蒸腾速率的非线性指数预测模型:ηt=0.6950exp（0.03158t-14.2492/pv+0.7606/Ψ）,经检验获得了满意的数值模拟结果。 相似文献
9.
[目的] 研究秦岭火地塘林区3种主要林型林冠层对不同pH值降雨水质的影响过程,为研究酸沉降对森林生态系统的影响提供基础。[方法] 以林区油松林、华山松林、锐齿栎林为研究对象,自制人工降雨器模拟降雨,分析各林分林冠穿透雨水化学物质浓度随降雨时间及降雨酸度的变化规律。[结果] ①模拟降雨10 min或20 min 3种林分林冠穿透雨中NH4+,NO3-,K+,Ca2+,Mg2+,Pb,Zn,Cd浓度达到峰值,降雨20～30 min后浓度降低并趋于稳定,随降雨时间延长总体上呈先升高后降低并趋于稳定的规律。②针叶林、阔叶林不同的叶组织特性影响林冠中化学物质淋洗量。相同pH值降雨淋洗,油松、华山松林冠穿透雨中NH4+,NO3-,K+,Ca2+,Mg2+,Pb,Zn,Cd浓度多表现为大于锐齿栎。③酸雨能促进林冠中化学物质淋失。对于同一树种,不同pH值降雨淋洗,林冠穿透雨中NH4+,K+,Ca2+,Mg2+,Pb,Cd浓度值及浓度变化幅度大小大体表现为：pH4.0 > pH5.0 > pH7.0。[结论] 根据林冠穿透雨水化学物质浓度随降雨时间动态变化规律,将林冠对穿透雨水质影响过程划分为降雨淋洗（降雨开始至降雨10 min或20 min）和降雨淋溶（降雨约20～30 min以后）两个阶段。降雨淋洗阶段,林冠层对水质变化影响大。 相似文献
10.
土地利用从水稻种植至蔬菜种植的转换对土壤中磷素赋存形态的影响 总被引：2，自引：0，他引：2
J. L. DARILEK HUANG Biao LI De-Cheng WANG Zhi-Gang ZHAO Yong-Cun SUN Wei-Xi SHI Xue-Zheng 《土壤圈》2010,20(2):137-145
Excess phosphorus (P) from agricultural soils contributes to eutrophication in water bodies. Samples (n=60) were taken from sites where rice paddies have been converted to vegetable fields for 0, < 10, 10-20, and > 20 years and analyzed for five inorganic P (Pi) fractions, three organic P (Po) fractions, and several soil parameters to investigate how land use conversion affects Pi and Po fractions in a peri-urban area of China with soils characteristic of many agricultural areas of Asia. Significant increases of 33, 281, 293, and 438 mg kg-1 were found for soluble and loosely bound Pi (SL-Pi), aluminum-bound Pi (Al-Pi), calcium-bound Pi (Ca-Pi), and iron-bound Pi (Fe-Pi), respectively, after conversion from rice paddies to vegetable fields. Most of the increase in Pi was in the form of Fe-Pi, which increased from 8% of total P (TP) on paddy soil to 31% on the soil with > 20-year vegetable cultivation, followed by Al-Pi, which increased from 2% to 19% of TP. For Po fractions, there was no significant change in P concentrations. The conversion of land use from paddy fields to high intensity vegetable fields was causing significant changes in soil P fractions. Management practices were causing a buildup of soil P, primarily in the Fe-Pi fraction, followed by Ca-Pi and Al-Pi fractions. If current trends continue, a 30%-70% increase in TP could be expected in the next 20 years. Farmers in the area should reduce P application and use to maximize P uptake. 相似文献
11.
为深入理解森林坡面土壤饱和导水率的空间变异,利用经典统计学和地统计学的方法研究六盘山华北落叶松人工林坡面不同土层土壤饱和导水率的空间异质性,并基于相关性分析揭示其空间变异的主要因素。结果表明:(1)随土层的加深,土壤饱和导水率逐渐增加,不同土层土壤饱和导水率的空间变异程度存在差异,表现为40—60 cm土层土壤饱和导水率为强变异,其他土层均为中等变异。(2)不同土层土壤饱和导水率的空间结构也存在差异,20—40,40—60,60—80 cm土层土壤饱和导水率表现为强烈的空间自相关性,0—20,80—100 cm土层土壤饱和导水率表现为中等空间自相关性。(3)坡面土壤饱和导水率与石砾含量、非毛管孔隙度、毛管持水量、田间持水量和毛管孔隙度显著相关。综上,研究坡面土壤饱和导水率具有较强的空间变异,石砾含量和土壤物理性质是影响研究坡面土壤饱和导水率空间分布的主要因素。 相似文献
12.
《Communications in Soil Science and Plant Analysis》2012,43(16):2182-2200
To gain additional knowledge and better understand forest soil management on a small scale, geostatistical analytical tools were employed to examine the spatial distribution in dry aggregate mean weight diameter (MWD) and other selected soil properties and to assess the possible relationships between MWD and other soil properties. Selected properties of forest soils collected along a 300-m transact in the Nimbia Forest Reserve of Nigeria exhibited moderate to high variability in distribution with sodium ion displaying the greatest variability [coefficient of variation (CV, 91.2%)] and principal component analysis revealed the exchange complex cluster as influencing total variation of field soil properties. The autocorrelation function showed significant spatial correlation from 1 lag in soil organic carbon up to 17 lags (51 m) in soil moisture content (θ). The spherical and Gaussian semivariogram models described the spatial structure of most soil properties; however, for clay, cation exchange capacity (CEC), and soil organic carbon (SOC), an exponential model analyzed their spatial dependence. 相似文献
13.
土壤水力学性质的空间变异对于区域土壤水分溶质循环模拟研究至关重要。基于Markov链的条件模拟是一种能融合多源信息技术的地统计学模拟方法,与传统插值法和基于变异函数的条件模拟相比有诸多优势。目前,该方法在土壤水力学性质空间变异性领域的研究并未全面展开。实现区域土壤水力学模型参数的随机模拟,对于实现区域土壤水分运动和溶质运移的随机模拟,分析土壤水力学性质空间变异性对土壤水分运动和溶质运移模拟结果的影响,特别是参数采样点变化对土壤水分运动和溶质运移结果影响的不确定性等研究都有重要意义。本文旨在综述基于Markov链的地统计学模拟在土壤学相关领域的研究进展,以期为区域模拟中面临的参数获取难题提供帮助,为区域农业生产管理,水分高效利用,农田生态环境保护提供科学依据。 相似文献
14.
The objective of this study was to quantify inherent spatial variability and spatial cross-correlation of the van Genuchten retention parameters and saturated hydraulic conductivity (Ks) of surface and subsurface layers in a calcareous Inceptisols (Khuzestan province, Iran) under sugarcane cropping. Measurements were performed on 100-cm3 undisturbed soil cores collected at 94 locations along a 30-m-long transect with horizontal sampling distance intervals of 0.3 and 1 m at soil depths of 0–40 and 40–80 cm, respectively. Spatial variability was investigated using conventional statistics and geostatistical techniques. Coefficient of variation (CV) varied from 8.2% (for shape parameter, n at 40–80 cm depth) to 256.7% (for Ks at 0–40 cm depth). The n parameter and saturated water content, θs, showed a small-scale spatial heterogeneity with a maximum CV of 11.3% for the first depth and 9.2% for the second depth. Most of the hydraulic parameters at both depths showed a spatial structure and convex experimental semivariograms with dominant spherical models with the influence range of 3.2–41 m. In most cases, the extent of spatial correlation scales of cross-semivariograms for pairs of cross-correlated hydraulic variables was found to be different with reference to those relating to the direct semivariograms of correlated variables. 相似文献
15.
退化红壤区不同模式重建森林土壤水分空间变异性 总被引：2，自引：1，他引：2
采用地统计学的方法,研究了江西泰和退化红壤区不同模式重建森林在高温干旱季节土壤水分空间变异规律及其分布格局。结果表明,在该研究尺度下,湿地松纯林、枫香纯林、湿地松与枫香混交林0~20 cm,20~40cm土层含水量分布都符合正态分布,都可较好地拟合成球状模型,表现出明显的空间相关性和空间分布格局。3种重建模式样地0~20 cm,20~40 cm层土壤含水量变异函数的基台值、变程都较无林荒地明显增大,而且基台值和变程在0~20 cm,20~40 cm两土层间的差异明显大于无林荒地,说明植被恢复以后,土壤水分的空间分布特征明显改变,空间变异性增强,空间变异的程度和尺度都明显增大,土壤水分的空间变异也具有较为明显的层次性。与纯林相比,湿地松×枫香混交林土壤水分的空间变异程度较低,水分分布趋于均匀化。 相似文献
16.
退化石灰岩红壤区四种人工林旱季土壤水分的空间变异 总被引：2，自引：2，他引：0
采用地统计学的方法,研究了江西修水退化石灰岩红壤区四种人工林在高温干旱季节土壤水分空间变异规律及其分布格局。结果表明:(1)不同类型人工林的土壤水分表现出不同的空间变异性。枫香纯林土壤水分的结构方差比为0·551,梾木×香椿混交林为0·730均介于0·25～0·75之间,表现出中等程度的空间相关性;青桐×桤木混交林的为0·841,香椿纯林的为0·934,均大于0·75,表现出强烈的空间相关性。(2)梾木×香椿、青桐×桤木混交林土壤水分在水平方向和垂直方向上空间变异程度比枫香纯林、香椿纯林低混交林土壤水分的分布更均匀。(3)0～10cm层土壤含水量的变异程度较10～20cm土层和20～40cm土层大,即随土层深度增加土壤水分分布趋于均匀。 相似文献
17.
The spatial variability of the saturated hydraulic conductivity (Ks) of a greenhouse banana plantation volcanic soil was investigated with three different permeameters: (a) the Philip-Dunne field permeameter, an easy to implement and low cost device; (b) the Guelph field permeameter; (c) the constant head laboratory permeameter. Ks was measured on a 14×5 array of 2.5 m×5 m rectangles at 0.15 m depth using the above three methods. Ks differences obtained with the different permeameters are explained in terms of flow dimensionality and elementary volume explored by the three methods. A sinusoidal spatial variation of Ks was coincident with the underlying alignment of banana plants on the field. This was explained in terms of soil disturbances, such as soil compaction, originated by management practices and tillage. Soil salinity showed some coincidence in space with the hydraulic conductivity, because of the irrigation system distribution, but a causal relationship between the two is however difficult to support. To discard the possibility of an artefact, the original 70 point mesh was doubled by intercalation of a second 14×5 grid, such that the laboratory Ks was finally determined on a 140 points 2.5 m×2.5 m square grid. Far from diluting such anisotropy this was further strengthened after inclusion of the new 70 points. The porosity (φ) determined on the same laboratory cores shows a similar sigmoid trend, thus pointing towards a plausible explanation for such variability. A power-law relationship was found between saturated hydraulic conductivity and porosity, Ksφn (r2=0.38), as stated by the Kozeny–Carman relation. A statistical reformulation of the Kozeny–Carman relation is proposed that both improved its predictability potential and allows comparisons between different representative volumes, or Ks data sets with different origin. Although the two-field methods: Guelph and Philip-Dunne, also follow a similar alignment trend, this is not so evident, suggesting that additional factors affect Ks measured in the field. Finally, geostatistical techniques such as cross correlograms estimation are used to further investigate this spatial dependence. 相似文献
18.
测定尺度对所测土壤导水参数及其空间变异性的影响 总被引：8，自引：1，他引：8
用 3种盘径 (14.4,2 0 ,30cm)的负压入渗仪在 2个供水负压 (1和 10cm)下 ,在 65个测点测定了田间水分入渗。基于入渗数据 ,计算了宏观毛管上升高度和 2个基模吸力的导水率。导水率和宏观毛管上升高度的值呈对数正态分布。用大盘径负压入渗仪测定获得的导水率和宏观毛管上升高度的空间连续性最好。当供水负压为 1cm ,盘径为 14.4cm(小盘径 ) ,导水率和宏观毛管上升高度的空间连续性没有表现出来。导水率的均值随测定尺度增加而趋于减少 ,宏观毛管上升高度的均值和标准偏差均随测定尺度增加而趋于减小。导水率和宏观毛管上升高度的样本半方差 ,半方差金砖方差 (nugget)和平台方差 (sill)随测定尺度增加而减少 相似文献
19.
The penetrometer resistance (PR) spatial variability in a Ferralsol under different soil moisture conditions was characterized through statistical and geostatistical methods. PR measurements were made in a 10-row, 10-columns, 3-m spacing grid at 20–30 cm depth using a hand-pushing penetrometer. Measurements were made for dry soil conditions (before irrigation) as well as 2 and 24 h after irrigation. The soil bulk density (BD) and the relative topographical altitudes (RT) were measured at the same locations. The PR spatial variability is normally distributed for dry soil conditions and after irrigation-water redistribution. A normal distribution fits also to the BD spatial variability. PR mean and coefficients of variations are lower for wet soil conditions and vary notably according to the soil moisture condition. The PR semivariance values are much higher for dry soil conditions than those found for wet soil conditions. However, the semivariogram of PR before irrigation shows almost a pure nugget effect. Irrigation yields a spatial structure in PR measurements. Despite the differences in the shown spatial structure, the range of the PR semivariograms before and 24 h after irrigation is about 8–10 m, which is very similar to the range of the BD semivariogram. The correlation coefficients between PR and the other measured variables are very small before and after irrigation, which could lead to the conclusion that those variables are not related at all. However, according to the co-dispersion coefficients plotted as a function of the separation lag, the correlation between those variables changes according to the separation distance. Particularly, PR and the RT show correlation 24 h after irrigation only for lags between 5 and 12 m. The results pointed out that PR spatial variability depends on soil moisture condition, soil BD and on several local features as microtopography. 相似文献
20.
典型绿洲区土壤盐分的空间变异特征 总被引：7，自引：2，他引：5
针对绿洲区存在的土壤盐化制约干旱区农业可持续发展问题,应用面域土壤信息调研采集,结合地统计学与GIS技术对新疆典型绿洲区土壤盐分空间变异特征进行研究。研究结果表明:0～30cm耕层土壤盐分呈现强变异性,30cm以下土层呈现中等变异。各土层土壤盐分均呈现中等空间自相关性,空间相关距离在24～28km范围内。各等级盐化土在不同深度土层的分布方位基本一致。各土层非盐化土面积均占主导地位,都占研究区总面积的69%以上;其次为轻度盐化土面积,占研究区总面积的19%～30%;各土层中度盐化土面积都在3.4%以下;重度盐化土仅在0～30cm土层有极少量分布。随着土层深度的增加,非盐化土和中度盐化土的面积逐渐减小,轻度盐化土面积逐渐增大。本研究对于指导干旱区绿洲农业生产、保障区域土壤资源可持续合理利用具有重要的理论价值和明确的实际应用前景。 相似文献