Multifractal characteristics and spatial variability of soil particle-size distribution in different land use patterns in a small catchment of the Three Gorges Reservoir Region,China

Characterizing soil particle-size distribution is a key measure towards soil property.The purpose of this study was to evaluate the multifractal characteristics of soil particle-size distribution among different land-use from a purple soil catchment and to generalize the spatial variation trend of multifractal parameters across the catchment.A total of 84 soil samples were collected from four kinds of land use patterns(dry land,orchard,paddy,and forest)in an agricultural catchment in the Three Gorges Reservoir Region,China.The multifractal analysis method was applied to quantitatively characterize the soil particle size distribution.Six soil particle size distribution(PSD)multifractal parameters(D(0),D(1),D(2),(35)a(q),(35)f[a(q)],α(0))were computed.Additionally,a geostatistical analysis was employed to reveal the spatial differentiation and map the spatial distribution of these parameters.Evident multifractal characteristics were found.The trend of generalized dimension spectrum of four land use patterns was basically consistent with the range of 0.8 to 2.0.However,orchard showed the largest monotonic decline,while the forest demonstrated the smallest decrease.D(0)of the four land use patterns were ranked as:dry land<orchard<forest<paddy,the order of D(1)was:dry land<paddy<orchard<forest,D(2)presented a rand-size relationship as dry land<forest<paddy<orchard.Furthermore,all land-use patterns presented asΔf[α(q)]<0.The rand-size relationship ofα(0)was same as D(0).The best-fitting model for D(0),D(1),D(2)andΔf[α(q)]was spherical model,forΔα(q)was gaussian model,and forα(0)was exponential model with structure variance ratio was 1.03%,49.83%,0.84%,1.48%,22.20%and 10.60%,respectively.The results showed that soil particles of each land use pattern were distributed unevenly.The multifractal parameters under different land use have significant differences,except forΔα(q).Differences in the composition of soil particles lead to differences in the multifractal properties even though they belong to the same soil texture.Farming behavior may refine particles and enhance the heterogeneity of soil particle distribution.Our results provide an effective reference for quantifying the impact of human activities on soil system in the Three Gorges Reservoir region.

Evaluation of Spatial Variability of Soil Properties in a Long-Term Experimental Tobacco Station in Southwest China

Analysis of the spatial variability of soil properties is important to arrange the experimental treatments in the experimental station. This paper aims to study the spatial structure of soil variables and their distribution in the Pengshui tobacco experiment station in Chongqing, China. Soil samples were taken from 289 soil points on 20 m grid in March 2012. Twenty-two soil chemical and physical properties were analyzed by classical statistical and geo-statistical methods. Soil pH, cation exchange capacity （CEC）, total phosphorus （TP）, available phosphorus （AP）, zinc （Zn）, magnesium （Mg） and sulphur （S） have the strong spatial dependence, with nugget/sill ratios of less than 25%. The others have the moderate dependence with nugget/sill ratios of 26.17% to 71.04%. Ranges of the spatial correlation varied from 51.30 m for chlorine （C1） to 594.90 m for TP. The clearly patchy maps of the nutrients showed the spatial distributions of the soil variables, which can be used for better management of experimental treatments, achieving reliable exoerimental results in the tobacco exnerimental station.Highlight： Scientific experimentation assumes the existence of random variability for soil attributes. This research was to evaluate the spatial variability of soil chemical and physical attributes and to interpolate the spatial distribution of soil properties in the tobacco experimental station in Chongqing. The result of this work can be used for the agricultural management of tobacco cultivation.

Effects of restoration modes on the spatial distribution of soil physical properties after land consolidation: a multifractal analysis

Soil physical properties(SPP)are considered to be important indices that reflect soil structure,hydrological conditions and soil quality.It is of substantial interest to study the spatial distribution of SPP owing to the high spatial variability caused by land consolidation under various land restoration modes in excavated farmland in the loess hilly area of China.In our study,three land restoration modes were selected including natural restoration land(NR),alfalfa land(AL)and maize land(ML).Soil texture composition,including the contents of clay,silt and sand,field capacity(FC),saturated conductivity(Ks)and bulk density(BD)were determined using a multifractal analysis.SPP were found to possess variable characteristics,although land consolidation destroyed the soil structure and decreased the spatial autocorrelation.Furthermore,SPP varied with land restoration and could be illustrated by the multifractal parameters of D1,ΔD,ΔαandΔf in different modes of land restoration.Owing to multiple compaction from large machinery in the surface soil,soil particles were fine-grained and increased the spatial variability in soil texture composition under all the land restoration modes.Plough numbers and vegetative root characteristics had the most significant impacts on the improvement in SPP,which resulted in the best spatial distribution characteristics of SPP found in ML compared with those in AL and NR.In addition,compared with ML,Δαvalues of NR and AL were 4.9-and 3.0-fold that of FC,respectively,andΔαvalues of NR and AL were 2.3-and 1.5-fold higher than those of Ks,respectively.These results indicate that SPP can be rapidly improved by increasing plough numbers and planting vegetation types after land consolidation.Thus,we conclude that ML is an optimal land restoration mode that results in favorable conditions to rapidly improve SPP.

Effect of Water Salinity on the Spatial Variability of Soil and Plant Parameters

Spatial pattern and interdependence of different soil and plant parameters were examined in green bean field experiment carried out at the Mediterranean Agronomic Institute of Bari （MAIB）, Italy. The study aimed to identify the spatial distribution of soil and plant parameters and their relationship at transects scale. The experiment consisted of three transects of 30 m length and 4.2 m width, irrigated with three different salinity levels （1 dSm＂1, 3 dSm1, 6 dSml）. Soil measurements （electrical conductivity and soil water content） were monitored along each transect in 24 sites, using TDR probe installed vertically at soil surface. Water storage was measured by using Diviner sensor for calculating directly the evapotranspiration fluxes along the whole soil profile under the different salinity levels imposed during the experiment. In the same 24 sites, crop monitoring involved measurements of Leaf Area Index （LAI）, Osmotic Potential （OP）, Root length Density （RID） and Evapotranspiration fluxes （ET）. Soil and plant properties were analyzed using both classical and geostatistical methods which included descriptive statistics, semivariograms and cross-semivariograms. Results indicated that moderate to large spatial variability existed across the field for soil and plant parameters, especially under the 6 dSm1 salinity treatment. A relatively satisfactory fit of the experimental cross-semivariogram was obtained for the 6 dS1, thus indicating similar spatial structures of the pairs of compared variables. By contrast, the experimental cross-semivariograms observed under the 3 dS~ treatment indicated no significant correlation structure between the compared variables. Overall, the results observed in the 3 dSm-1 were not significantly different from those obtained in the 1 dSm-1 transect and suggested a general insensitivity of the crop response to those levels of salinity.

Spatial variability and pattern analysis of soil properties in Dehui city, Jilin province

Based on regionalized variable theory, semivariograms of geo-statistics wereused to research the spatial variation of soil properties quantitatively. The results showed thatthe semivariogram of soil organic matter is best described by spherical model, the best model forsemivariograms of soil total N and available K is exponential models and that of available P belongsto linear with sill model. Those soil properties have different spatial correlations respectively,the lag of organic matter is the highest and that of available P is the lowest, the spatialcorrelation of N and available K belongs to moderate degree. Spatial heterogeneities are differenttoo, the degree of organic matter and total N are higher, the degree of available K is in the nextplace and that of available P is the lowest. Influenced by the shape, topography and soil of thestudy area, all isotropies of available P are obvious in all directions while anisotropies of othersare manifested. According to the analytical results, supported by GIS, Kriging and IDW methods areapplied to describe and analyze the spatial distribution of soil properties. The results indicatethat soil organic matter, total N and available K are distributed regularly from northeast tosouthwest, while available P is distributed randomly.

Spatial Variability of Soil Chemical Properties in the Reclaiming Marine Foreland to Yellow Sea of China

Precise information about the spatial variability of soil properties is essential in developing site-specific soil management, such as variable rate application of fertilizers. In this study the sampling grid of 100 m × 100 m was established to collect 1 703 soil samples at the depth of 0-20 cm, and examine spatial patterns including 13 soil chemical properties （pH, OM, NH4^＋, P, K, Ca, Mg, S, B, Cu, Fe, Mn, and Zn） in a 1 760 ha rice field in Haifeng farm, China, from 6th to 22nd of April, 2006, before fertilizer application and planting. Soil analysis was performed by ASI （Agro Services International） and data were analyzed both statistically and geostatistically. Results showed that the contents of soil OM, NH4^＋, and Zn in Haifeng farm were very low for rice production and those of others were enough to meet the need for rice cultivation. The spatial distribution model and spatial dependence level for 13 soil chemical properties varied in the field. Soil Mg and B showed strong spatial variability on both descriptive statistics and geostatistics, and other properties showed moderate spatial variability. The maximum ranges for K, Ca, Mg, S, Cu and Mn were all - 3 990.6 m and the minimum ranges for soil pH, OM, NH4^＋, P, Fe, and Zn ranged from 516.7 to 1 166.2 m. Clear patchy distribution of N, P, K, Mg, S, B, Mn, and Zn were found from their spatial distribution maps. This proved that sampling strategy for estimating variability should be adapted to the different soil chemical properties and field management. Therefore, the spatial variability of soil chemical properties with strong spatial dependence could be readily managed and a site-specific fertilization scheme for precision farming could be easily developed.

The effect of environmental factors on spatial variability in land use change in the high-sediment region of China＇s Loess Plateau

In areas with topographic heterogeneity, land use change is spatially variable and influenced by climate, soil properties, and topography. To better understand this variability in the high-sediment region of the Loess Plateau in which soil loss is most severe and sediment diameter is larger than in other regions of the plateau, this study builds some indicators to identify the characteristics of land use change and then analyze the spatial variability as it is affected by climate, soil property, and topography. We build two indicators, a land use change intensity index and a vegetation change index, to characterize the intensity of land use change, and the degree of vegetation restoration, respectively. Based on a subsection mean method, the two indicators are then used to assess the spatial variability of land use change affected by climatic, edaphic, and topographic elements. The results indicate that： 1） Land use changed significantly in the period 1998-2010. The total area experiencing land use change was 42,302 km2, accounting for 22.57%of the study area. High-coverage grassland, other woodland, and forest increased significantly, while low-coverage grassland and farmland decreased in 2010 compared with 1998.2） Land use change occurred primarily west of the Yellow River, between 35 and 38 degrees north latitude. The four transformation types, including （a） low-coverage grassland to medium-coverage grassland, （b） medium-coverage grassland to high-coverage grassland, （c） farmland to other woodland, and （d） farmland to medium-coverage grassland, were the primary types of land use change, together constituting 60% of the area experiencing land use change. 3） The spatial variability of land use change was significantly affected by properties of dryness/wetness, soil conditions and slope gradient. In general, land use changed dramatically in semi-arid regions, remained relatively stable in arid regions, changed significantly in clay-rich soil, remained relatively stable in clay-poor soil, changed dramatically in steeper slopes, and remained relatively stable in tablelands and low-lying regions. The increase in vegetation coincided with increasing changes in land use for each physical element. These findings allow for an evaluation of the effect of the Grain to Green Program, and are applicable to the design of soil and water conservation projects on the Loess Plateau of China.

Uncertainties of thermal boundaries and soil properties on permafrost table of frozen ground in Qinghai-Tibet Plateau

In the permafrost regions of the Qinghai-Tibet Plateau(QTP),the permafrost table has a significant effect on the stability of geotechnical engineering.The thermal boundaries and soil properties are the key factors affecting the permafrost table.Complex geological environments and human activities can lead to the uncertainties of thermal boundaries and soil properties.In this paper,an array of field experiments and Monte Carlo(MC)simulations of thermal boundaries and soil properties are carried out.The coefficient of variation(COV),scale of fluctuation(SOF),and autocorrelation distance(ACD)of uncertainties of thermal boundaries and soil properties are investigated.A stochastic analysis method of the probabilistic permafrost table is then proposed,and the statistical properties of permafrost table on the QTP are computed by self-compiled program.The proposed stochastic analysis method is verified with the calculated and measured temperature observations.According to the relationship between ACD and SOF for the five theoretical autocorrelation functions(ACFs),the effects of ACF,COV,and ACD of soil properties and the COV of thermal boundaries on the permafrost tables are analyzed.The results show that the effects of different ACFs of soil properties on the standard deviation(SD)of permafrost table depth are not obvious.The SD of permafrost table depth increases with time,and the larger the COVs of thermal boundaries and soil properties,the deeper the SD of permafrost table;the longer the ACD of soil properties,the shallower the SD of permafrost table.This study can provide a reference for the stability analysis of geotechnical engineering on the QTP considering the uncertainties of thermal boundaries and soil properties.

近江平原区土壤水力参数及相关理化性质空间分布与影响因素

为研究土壤水力参数的空间分布特征,并揭示相关影响因素,以江汉平原典型近江农业区为研究单元,采集不同类型农用地的浅层(0~40 cm)原状和扰动土样,测定其水力参数和相关理化性质,揭示各水力参数及相关理化性质的空间分布特征,比较不同样地各参数和性质的差异,并分析相关影响因素。结果表明:研究区土壤各基本理化性质(土壤机械组成、有机质含量、容重、直径>0.1 mm和>0.3 mm大孔隙含量)和水力参数(饱和含水量(θ_(s))、残余含水量(θ_(r))、水分特征曲线拟合参数α和n、田间持水量(θ_(f))、凋萎系数(θ_(w))和最大有效水含量(θ_(AW)))均具有明显的空间异质性;近江区土壤机械组成、有机质含量、容重等部分理化性质与距江远近具有较强的空间相关性;直径>0.1 mm和>0.3 mm大孔隙含量,θs和θr,以及θf和θ_(AW)的空间分布特征相似。不同样地的有机质含量、容重和直径>0.3 mm大孔隙含量具有显著差异。土壤理化性质的差异显著影响了Ks和水分特征曲线参数(特别是θs和n)。不同农用地土壤的水力性质也存在差异,稻田和旱地的入渗性能较好,表现为最高的中位Ks(18.7 cm/h),其他样地的Ks差异较小(9.2~10.5 cm/h)。菜地的持水能力最强,表现为较高的θf(0.46 cm^(3)/cm^(3))、θw(0.07 cm^(3)/cm^(3))和θAW(0.39 cm^(3)/cm^(3)),其他样地的土壤水力参数差异较小。河流冲积物的分布显著影响了研究区农用地的土壤机械组成,对容重和有机质含量分布也有一些影响;而人类耕作活动可以显著改变土壤的有机质含量、大孔隙含量和容重,但对机械组成影响较小;自然要素和人为活动的共同作用影响了各水力参数的分布特征。在近江农业区开展土壤调查和农业生产规划时,需要考虑河流冲积物的分布特征。

塿土土壤水力特性空间变异的多重分形分析

为探讨塿土土壤水力特性的空间分布特征,对杨凌示范区大寨乡小麦与玉米轮作地进行直线分布土壤取样,室内测定了土壤水分特征曲线、饱和导水率、土壤含水率、容重等土壤水力特性,用Brooks-Corey模型对土壤水分特征曲线进行拟合,采用多重分形方法对Brooks-Corey模型参数(θs、α、n)、饱和导水率(Ks)、土壤含水率(θ)、容重(ρ)等进行空间变异性分析。结果表明:在全部采样方向上Ks、α及n的变异性较强,θs、θ及ρ表现为弱变异;不同采样方向上土壤水力特性参数具有多重分形特征;不同采样方向上θs、θ及ρ的多重分形结构较弱,空间变异性不强;不同采样方向上Ks、α及n的多重分形结构明显,广义分形维数分别为0.7～1.90、.6～1.2、0.9～1.1,空间变异性较强,且Ks比α和n具有更为复杂的空间分布结构。

土壤水盐空间异质性及尺度效应的多重分形

为了揭示研究区域林地内土壤含水率和电导率的空间分布特征及尺度效应,利用多重分形方法,对杨凌一林地内不同采样时间和不同采样面积下土壤含水率和电导率的空间异质性进行了研究。结果表明:3种采样面积下土壤含水率和电导率的空间异质性都分别随平均含水率和电导率的增大而减弱。随采样面积的增大,平均含水率和电导率较高时,土壤含水率的空间异质性趋于增强,土壤电导率的尺度效应不明显;平均含水率和电导率较低时,土壤含水率和电导率的空间分布都存在明显的斑块结构。不同采样时间和不同采样面积下土壤含水率和电导率的多重分形谱的形态有所差异,表明引起他们空间异质性的信息有所不同。多重分形分析能揭示出较多的采样林地内土壤含水率和电导率分布的局部信息。

不同土层土壤特性空间变异性关系的联合多重分形研究

应用联合多重分形理论研究了0～20 cm土层土壤含水率、土壤电导率、砂粒含量、粘粒含量、粗粉粒含量、土壤粒径分布体积分形维数、土壤容重、有机质含量的空间变异性与20～40 cm土层对应变量空间变异性在多尺度上的相互关系。结果表明:相对于0～20 cm土层上述变量的空间变异性,20～40 cm土层粗粉粒含量、有机质含量空间变异性的变化率最大,土壤电导率、粘粒含量、土壤粒径分布体积分形维数空间变异性的变化率最小,砂粒含量、土壤含水率、土壤容重空间变异性的变化率介于两者之间;多尺度上,0～20 cm土层土壤含水率、土壤容重、有机质含量、粘粒含量、砂粒含量、土壤电导率、土壤粒径分布体积分形维数、粗粉粒含量与20～40 cm土层对应变量空间变异性在多尺度上的相关性依次减弱。

土壤水盐空间变异尺度效应的研究

水文学和土壤学中的尺度问题是目前水土科学研究的前沿课题之一。该文利用空间信息科学——地质统计学、根据设计的各种田间网格,在一维和二维(平面)空间中初步研究了黄河河套平原长胜试验区中小尺度的土壤水分和盐分随采样尺度所表现出的空间变异(结构性)的某些规律,表明采样尺度的划分和选取与水分和盐分的空间变异性大小有密切关系,尺度效应的研究对于指导农业技术研究中野外采样系统设计、节省外业调查的工作量及科学地进行内业计算、评估和揭示农业工程中具有地学特征的区域性自然规律有重要作用。

不同土层土壤水分特征曲线的空间变异及其影响因素

利用多重分形和联合多重分形方法,对陕西杨凌地区0～20 cm和20～40 cm土层van Genuchten模型参数的空间变异性及其影响因素进行了研究。结果表明:0～20 cm和20～40 cm土层参数α都具有明显的多重分形特征,空间变异性较强,且分别是由低值和高值分布引起的;参数n和θs的多重分形特征不明显,空间变异性较弱。0～20 cm和20～40 cm土层van Genuchten模型参数与土壤物理特性的相关特征并不完全相同,在观测尺度上,0～20 cm土层参数α与Sand、Silt显著相关,参数n与Sand、SOM显著相关,θs与Sand显著相关;20～40 cm土层参数α与SOM显著相关,参数n和θs都与Sand、Silt、SOM显著相关;在多尺度上,0～20 cm土层参数α与Sand、Silt的相关程度最高,20～40 cm土层参数α与BD、SOM的相关程度最高。

黄土区采煤塌陷对土壤水力特性的影响

通过对山西省平朔矿区塌陷区、原地貌和复垦区进行调查采样和实验室分析,研究采煤塌陷对土壤容重、含水量、田间持水量、饱和导水率和土壤崩解速率等指标的影响。结果表明：塌陷区土壤容重、含水量和田间持水量处于弱变异到中等变异区间,饱和导水率和崩解速率均为强变异;塌陷虽使土壤容重增加,但影响幅度不大;土壤含水量受塌陷影响规律不明显;田间持水量受塌陷影响明显（p〈0.05）,较未受损地区降低6.2%-15.5%;在采煤塌陷的影响下,土壤饱和导水率和崩解速率显著增加（p〈0.05）;复垦区土壤水力特性与原地貌没有显著差异（p〉0.05）,且各层次之间差异性也不显著（p〉0.1）。

吉林省德惠市土壤特性空间变异特征与格局

基于区变量理论,通过地统计学的半变异函数定量研究吉林省中部德惠市土壤有机质、全氮、速效钾和速效磷的空间异质性特征。表明土壤有机质的理论模型属于球状模型、全氮和速效钾的理论模型为指数模型、速效磷则属于有基台值的线状模型。空间结构上,有机质具有很强的空间相关性,全氮和速效钾的空间相关性属于中等程度,而速效磷则具有弱相关性。四种土壤养分的空间自相关范围具有明显的差异,有机质和全氮的有效变程最大,速效钾次之,速效磷的有效变程最小。受研究区形状、地形及土壤母质区域性差异的影响,速效磷各向同性显著,其他养分各向带状性比较明显。根据空间分异的分析结果,在GIS支持下,采用Kriging和IDW两种插值方法,分析研究区土壤养分的空间格局,表明土壤有机质、全氮、速效钾均自东北向西南有规律地分布;速效磷分布的随机性较强,较前三者结构性特征不明显。

土壤入渗特性的空间变异性及土壤转换函数

以在杨陵一级阶地上进行的入渗试验为基础,利用多重分形和联合多重分形方法,研究分析了土壤入渗特性在多尺度上的空间变异性及与土壤物理特性的相关性,并在此基础上建立了土壤入渗特性的土壤转换函数。研究表明:土壤入渗特性具有多重分形特征,观测尺度上,稳定入渗率、前30 min累积入渗量的空间变异都主要由粗粉粒和粘粒含量的空间变异造成。在多尺度上,稳定入渗率的空间变异受土壤容重、粗粉粒和粘粒含量的空间分布影响显著,前30 min累积入渗量的空间变异受粗粉粒和粘粒含量的空间分布影响显著,与观测尺度上的影响因素相同。基于联合多重分形分析建立的稳定入渗率的土壤转换函数的计算误差较小,前30 min累积入渗量的土壤转换函数的计算误差较大。

崇明县土壤主要理化指标的空间分布与变异特征

于上海市崇明县(崇明岛、长兴岛、横沙岛3岛)采集0～20cm表层土壤样品128个,采用经典统计学和地统计学相结合的方法,分析土壤有机质、全氮、有效磷、有效钾含量和土壤电导率、容重、pH值等数据,研究土壤特性的空间分布规律。结果表明:崇明3岛有效磷和电导率的分布具有强变异性,pH值的变异强度最弱,其他土壤特性均具有中等变异强度。土壤容重和pH值具有很强的空间相关性,而土壤有机质、全氮、有效磷和有效钾的空间相关性最弱,其分布受随机因素影响较大。Kriging空间插值分析表明,受农事活动和城镇效应的影响,崇明岛土壤有机质和全氮含量高值区主要集中于人为活动比较密集的地区,土壤容重和pH值分布趋势基本一致,呈现由东西两端向岛中央递减的趋势。崇明岛土壤有机质、全氮、有效磷和有效钾含量两两间呈显著相关关系(α=0.01)。

基于多重分形理论的农田土壤特性空间变异性分析

土壤性质是影响土壤水分运动和溶质迁移的重要因素,土壤特性的空间变异性研究对于农田土壤质量管理具有重要意义.为定量研究土壤特性空间变异性的复杂程度,本文以再生水灌区农田土壤为研究对象,应用分形和多重分形理论定量分析了农田土壤颗粒含量、土壤容重、饱和含水量、孔隙度等土壤特性的空间变异性.结果表明:土壤容重、孔隙度的分形维数D较大,其空间分布具有较大的随机性,即空间分布的均匀性较好;土壤特性的空间分布具备多重分形特征,多重分形谱的谱宽Δα可以定量表征土壤属性空间分布的不规则特征,饱和含水量的多重分形谱谱宽Δα最大,其空间分布的不规则形最大;大值数据对于砂粒、容重和饱和含水量空间变异性的贡献率较大.因此,多重分形参数可以作为定量反映土壤特性空间变异性的潜在指标.

基于GPS和GIS的田间土壤特性空间变异性的研究

以一块面积约为 13 .3 hm2 的冬小麦田为研究区 ,利用 GPS接收机定位 ,按 5 0 m× 5 0 m设置网格 ,共取 63个采样点 ,测定土壤表层 (2 0 cm)内的土壤有机质、全氮、碱解氮、速效磷、速效钾、容重、田间土壤含水率和电导率 ,研究麦田土壤特性的空间变异规律。采用传统统计学和地统计学相结合的方法对所取的数据进行了分析 ,利用 Arcview3 .2软件的空间分析功能 ,绘制了表达这些土壤特性随机性和结构性的半方差图和空间分布图。研究结果表明 :所有土壤特性均服从正态分布 ;土壤容重具有弱变异强度 ,其它土壤特性具有中等变异强度 ;土壤有机质、全氮、碱解氮、速效钾和电导率具有很强的相关性 ,土壤容重、速效磷和含水率具有中等强度的空间相关性 ,土壤特性的相关距变化范围为 2 46.8～ 42 6.8m。该成果可为农田的定位施肥、灌溉以及其它的农田精细管理提供依据。