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1.
Pingping Jiang Zhuoqiong He Newell R. Kitchen Kenneth A. Sudduth 《Precision Agriculture》2009,10(2):111-127
Understanding relationships of soil and field topography to crop yield within a field is critical in site-specific management
systems. Challenges for efficiently assessing these relationships include spatially correlated yield data and interrelated
soil and topographic properties. The objective of this analysis was to apply a spatial Bayesian hierarchical model to examine
the effects of soil, topographic and climate variables on corn yield. The model included a mean structure of spatial and temporal
co-variates and an explicit random spatial effect. The spatial co-variates included elevation, slope and apparent soil electrical
conductivity, temporal co-variates included mean maximum daily temperature, mean daily temperature range and cumulative precipitation
in July and August. A conditional auto-regressive (CAR) model was used to model the spatial association in yield. Mapped corn
yield data from 1997, 1999, 2001 and 2003 for a 36-ha Missouri claypan soil field were used in the analysis. The model building
and computation were performed using a free Bayesian modeling software package, WinBUGS. The relationships of co-variates
to corn yield generally agreed with the literature. The CAR model successfully captured the spatial association in yield.
Model standard deviation decreased about 50% with spatial effect accounted for. Further, the approach was able to assess the
effects of temporal climate co-variates on corn yield with a small number of site-years. The spatial Bayesian model appeared
to be a useful tool to gain insights into yield spatial and temporal variability related to soil, topography and growing season
weather conditions.
相似文献
| Pingping JiangEmail: |
2.
县域尺度表层土壤质地空间变异与因素分析 总被引：10，自引：1，他引：9
【目的】以北京市平谷区为研究区域,采用传统统计和地统计学相结合的方法研究县域尺度下土壤质地空间变异的规律,探究土壤质地空间变异的机理。【方法】采用Levine’s方法进行方差奇次性检验,根据检验结果选取最小显著性差方法(least-significant difference,LSD)对土壤颗粒组成与高程、母质、土地利用和水域分布关系进行研究。空间预测采用普通克里格法,鉴于土壤质地属于成分数据,插值前对原始数据进行对称对数比转换。【结果】不同高程组、母质类型、土地利用类型及水域缓冲区组各颗粒平均含量存在一定的差异性,不同高程组和母质类型的土壤颗粒组成之间的差异性比不同土地利用类型和水域缓冲区明显。总体而言,研究区内随着海拔高度的降低,土壤颗粒呈现由粗变细的趋势;由石英含量较高的酸性岩母质发育的土壤土壤颗粒较粗;菜地土壤颗粒相对较细;随着离水域距离的增大,土壤砂粒含量呈增加趋势。地统计分析结果显示,土壤质地各颗粒表现出极强的空间自相关性,空间变异主要由结构性因素引起。各颗粒空间插值结果表明,土壤各颗粒组成空间分布总体趋势特征比较明显。【结论】传统统计分析和地统计学相结合的方法能够系统和全面地揭示土壤质地空间变异的确定性和随机性,研究区土壤质地空间格局主要受地形、母质等自然因素影响。经过对称对数比转换后,土壤质地各颗粒组成空间预测结果满足成分数据空间插值的要求。 相似文献
3.
João M. Serrano José O. Peça José R. Marques da Silva Shakib Shahidian 《Precision Agriculture》2011,12(2):214-232
Several methods are described that could be used by a farm manager to define the spatial and temporal stability within a field
from a series of yield maps. A quantitative analysis of soil phosphate concentration and pasture dry matter yield data over
4 years (2004–2007) were investigated to identify the spatial and temporal stability in a 6 ha pasture field. The data were
combined into two maps that characterize the spatial and temporal variation recorded over the 4 years. The two maps were then
combined to create a single map with five management classes, each with different characteristics that can have an impact
on the way the field is managed. These categories are: high yielding and stable, high yielding and moderately stable, low
yielding and stable, low yielding and moderately stable and unstable. The unstable class represents 83 and 93% of the total
area with regard to soil phosphate concentration and pasture dry matter yield, respectively. Results from this study show
that the significant temporal stability found cancels out over time, leaving a relatively homogenous map of spatial variation.
The implication of the findings is that each pasture field should be managed according to the current year’s conditions. These
results also justify a further study that evaluates the soil phosphorous dynamics under Mediterranean conditions. 相似文献
4.
A. C. C. Bernardi G. M. Bettiol R. P. Ferreira K. E. L. Santos L. M. Rabello R. Y. Inamasu 《Precision Agriculture》2016,17(6):737-752
Knowledge of the spatial variability of soil properties and of forage yield is needed for informed use of soil inputs such as variable rate technology (VRT) for lime and fertilizers. The objective of this research was to map and evaluate the spatial variability of soil properties, yield, lime and fertilizer needs and economic return of an alfalfa pasture. The study was conducted in a 5.3 ha irrigated alfalfa pasture in Sao Carlos, SP, Brazil that was directly grazed and intensively managed in a 270-paddock rotational system. Alfalfa shoot dry matter yield was evaluated before grazing. Soil samples were collected at 0–0.2 m depth, and each sample represented a group of 2 or 3 paddocks. Apparent soil electrical conductivity (ECa) was measured with a contact sensor. The cost of producing 1 ha of alfalfa was estimated from the amount of lime and fertilizer needed and was then used to estimate the total cost of production for the dairy system. The alfalfa dry matter yield was used to simulate the pasture stocking rate, milk yield, gross revenue and net profit. The spatial variability of soil properties and site-specific liming and fertilizer needs were modeled using semi-variograms with VESPER software, the soil fertility information and economic return were modeled with SPRING software. The results showed that geostatistics and GIS were effective tools for revealing soil and pasture spatial variability and supporting management strategies. Soil nutrients were used to classify the soil spatial distribution map and design site-specific lime and fertilizer application maps. Spatial variation in forage and spatial estimates of stocking and milk yield are adequate pasture management tools. Spatial analyses of needs, forage availability and economic return are management tools for avoiding economic problems, as well as potential environmental problems, caused by unbalanced nutrient supplies and over- or under-grazing. 相似文献
5.
Jitka Kumhálová František Kumhála Milan Kroulík Štěpánka Matějková 《Precision Agriculture》2011,12(6):813-830
Quantitative knowledge of the factors and interactions affecting yield is essential for site-specific crop management. One
of the factors that frequently affects yield is topography. The aims of this study were to compare elevation data obtained
from a combine harvester yield monitor and a hand RTK-GPS, and to evaluate the relationships between the spatial variation
of cereal yield, selected crop nutrient concentration and topographic attributes derived from the two sources of elevation
data. Simple models of elevation, slope and flow accumulation were created from the data of an experimental field in the Czech
Republic, and the relations between yield and soil nitrogen and organic carbon contents and topography were determined over
a four-year period. The models of elevation, slope and flow accumulation were compared with the yield, and soil nitrogen and
organic carbon contents during the growing seasons of 2004, 2005, 2006 and 2007 in relation to total precipitation and temperature.
The relationship between yield and topographic attributes was evaluated with the help of geostatistical methods. The results
of correlation analysis among the variables were evaluated statistically by forward stepwise linear regression. No significant
differences between elevation data from the combine harvester yield monitor and RTK-GPS were found. There was a significant
relation between yield and crop nutrient concentration with topography. The correlation coefficients between flow accumulation
and yield were weak for the wetter years and strong for the drier years. 相似文献
6.
Soils occupied by dryland pastures usually have low fertility but can exhibit a high spatial variability. Consequently, logical application of fertilisers should be based on an appropriate knowledge of spatial variability of the main soil properties that can affect pasture yield and quality. Delineation of zones with similar soil fertility is necessary to implement site-specific management, reinforcing the interest of methods to identify these homogeneous zones. Thus, the formulation of the objective Rasch model constitutes a new approach in pasture fields. A case study was performed in a pasture field located in a montado (agrosilvopastoral) ecosystem. Measurements of some soil properties (texture, organic matter, nitrogen, phosphorus, potassium, cation exchange capacity and soil apparent electrical conductivity) at 24 sampling locations were integrated in the Rasch model. A classification of all sampling locations according to pasture soil fertility was established. Moreover, the influence of each soil property on the soil fertility was highlighted, with the clay content the most influential property in this sandy soil. Then, a clustering process was undertaken to delimit the homogeneous zones, considering soil pasture fertility, elevation and slope as the input layers. Three zones were delineated and vegetation indices (normalized difference vegetation index, NDVI, and normalized difference water index, NDWI) and pasture yield data at sampling locations were employed to check their differences. Results showed that vegetation indices were not suitable to detect the spatial variability between zones. However, differences in pasture yield and quality were evident, besides some key soil properties, such as clay content and organic matter.
相似文献7.
分析了山东省近8年小麦生育期内气象三因素变化及旬气象因子与旱地小麦主要农艺和产量性状的相关性。结果表明:2003～2010年小麦生育期内降水量减少和日照时数增加的趋势较为明显,积温呈降低的趋势,但变化不明显。生育期内84个气象因子中有25个因子与旱地小麦主要农艺或产量性状呈显著或极显著相关,其中旬降水量有6个因子,旬日照时数有9个因子,旬平均气温有10个因子。因此,在今后旱地小麦品种选育过程中,应结合日照和气温等气象因子变化特点进行选择,从而提高选育成功率。 相似文献
8.
9.
Andrew Hall David W. Lamb Bruno P. Holzapfel John P. Louis 《Precision Agriculture》2011,12(1):103-117
Remote optical imaging can rapidly acquire information describing spatial variability in vineyard block performance. Canopy
characteristics were derived from very high spatial resolution (0.25 m) optical imagery of a Cabernet Sauvignon vineyard acquired
at various canopy growth stages. Within-season changes to correlation coefficients between vineyard canopy and ultimate composition
and yield of harvested fruit were then investigated. Canopy area and density were observed to have significant relationships
with yield and fruit quality indicators including berry size, anthocyanins and total phenolic content, but less significant
relationships with total soluble solids. The strength and type of correlation varied with canopy growth stage. For anthocyanins
and total phenolic content, correlations varied from non-significant before flowering to negative after flowering. For berry
weight and yield, correlations varied from negative before flowering to positive after flowering. For total soluble solids,
there were some significant relationships but no clear temporal pattern. The results confirm that remote sensing is a useful
tool to determine spatial variability in fruit composition and yield. However, both the timing of image acquisition and the
way in which canopy is quantified are important determinants of the direction and strength of correlations with fruit composition
and yield. 相似文献
10.
11.
利用长治地区11个气象观测台站1960—2013年逐月降水资料,运用小波分析、突变分析、主分量分析等方法,对近54年来长治地区干旱事件的时空异常分布和变化特征等进行了综合分析。结果表明,近54年来长治地区降水的分布特征是东少西多,区域内干旱频繁;长子县是长治地区干旱发生最为频繁、也是近年来旱情趋于严重的地区。从长治降水变化的分布型来看,全区一致旱涝的分布型占主要地位,其所贡献的方差达总方差的70%以上。长治地区降水存在着年代际变化(周期为准4~14年)和年际变化(周期为准2~4年)2个显著的振荡特征;1972—2013年长治地区降水有逐渐减少的趋势,且从1972年开始可能出现了趋于明显减少的气候突变。 相似文献
12.
辽宁省农业干旱频发区首场透雨气候特征 总被引：1，自引：0，他引：1
利用1961~2013年辽宁省农业干旱易发区春播期首场透雨出现的日期及首场透雨量资料,采用线性回归、M-K检验法,分析了近53年该区春播期首场透雨出现的日期及首场透雨量的时空分布及气候学变化特征。结果表明,辽宁省农业干旱频发区透雨发生日期较晚,透雨量较少。透雨发生日期和透雨量空间分布均呈东南至北部方向逐渐递减的特征,沿海各站春播期首场透雨量普遍高于内陆地区。区域平均透雨发生日期和透雨量均有年际变化特征,但趋势不明显。各站春播期首场透雨发生日期多呈随时间逐渐提前、透雨量多呈增多趋势,但变化趋势均未通过显著性检验。研究时段内无透雨过程出现的个例占总数的8.4%,内陆及西部各站较沿海及其他地区更易出现春播期无透雨现象。 相似文献
13.
[目的]对渭干河-库车河典型绿洲范围内的土壤盐分离子空间变异进行研究,以期了解该三角洲土壤离子的空间相关性,揭示季节变化对土壤8大离子分布的影响。[方法]针对目前存在的土壤盐渍化问题,以渭干河-库车和典型三角洲绿洲为研究区,运用经典统计学和地统计学相结合的方法研究了表层土壤8大离子含量的时空变异特征,绘制了土壤盐分离子的随机性和结构性的空间分布图。[结果]在研究区中所有盐分离子含量数据经K-S检验均符合正态分布,不同季节的盐分离子含量变异性不同,10月的变异性高于4月,这可能是是由于10月降雨量小于4月,盐分离子随着强蒸发被带到土壤表面,盐分离子含量高;半方差分析得出盐分离子均表现为高强度的空间自相关性,但程度有所差异;空间分布特征表明,大部分盐分离子的空间结构性都较好,但2010年4月采集土样的Ca2+和Mg2+以及2010年10月份采集土样的Mg2+均适合线性模型,所以空间结构性较差,同时也表现出研究区特有的土壤盐分分布特征,这与研究区盐渍化主要是氯化物-硫酸盐型相一致。[结论]该研究结果为渭干河-库车河三角洲盐渍化土壤的分区、改良和利用提供了理论基础。 相似文献
14.
[目的]对渭干河-库车河典型绿洲范围内的土壤盐分离子空间变异进行研究,以期了解该三角洲土壤离子的空间相关性,揭示季节变化对土壤8大离子分布的影响。[方法]针对目前存在的土壤盐渍化问题,以渭干河-库车和典型三角洲绿洲为研究区,运用经典统计学和地统计学相结合的方法研究了表层土壤8大离子含量的时空变异特征,绘制了土壤盐分离子的随机性和结构性的空间分布图。[结果]在研究区中所有盐分离子含量数据经K-S检验均符合正态分布,不同季节的盐分离子含量变异性不同,10月的变异性高于4月,这可能是是由于10月降雨量小于4月,盐分离子随着强蒸发被带到土壤表面,盐分离子含量高;半方差分析得出盐分离子均表现为高强度的空间自相关性,但程度有所差异;空间分布特征表明,大部分盐分离子的空间结构性都较好,但2010年4月采集土样的Ca2+和Mg2+以及2010年10月份采集土样的Mg2+均适合线性模型,所以空间结构性较差,同时也表现出研究区特有的土壤盐分分布特征,这与研究区盐渍化主要是氯化物-硫酸盐型相一致。[结论]该研究结果为渭干河-库车河三角洲盐渍化土壤的分区、改良和利用提供了理论基础。 相似文献
15.
基于地形梯度的淇河流域土地利用时空变异分析 总被引：2，自引：0，他引：2
地形作为最基本的自然地理要素,在一定程度上影响着土地利用变化,对土地利用空间格局的形成具有重要影响。以太行山淇河流域为例,借助DEM提取高程、坡度信息,采用转移矩阵、区域统计分析和地形分布指数系统分析淇河流域1990—2015年间土地利用时空变异特征,定量分析了地形梯度上土地利用变化。结果表明:25年来变化最大的土地利用类型为耕地和草地,耕地面积净减少量最大,林地次之;草地面积净增加最多,建设用地面积净增加次之,未利用地面积变化不大。耕地、建设用地、草地生态系统集中于低地形梯度区,而林地集中于高地形梯度区;耕地、林地在低海拔区域面积呈减少趋势,水域和建设用地增加集中在低海拔地区;耕地在低坡度区域内呈现减少趋势,建设用地在低坡度地区增加集中。 相似文献
16.
[目的]比较4种空间插值方法的插值效果,分析研究区域降水空间分布特征。[方法]以陕西省关中—陕南地区为例,采用该地区72个气象观测站点59年的降水量资料,结合GIS空间插值技术,以国际科学数据共享服务网站30 m×30 m网格DEM为基础,选取IDW、普通克里金插值法、协同克里金插值法和径向基函数插值法对关中—陕南地区72个观测站多年平均降水量进行空间插值,并分区域随机选取其中10个站点的降水量数据对4种插值方法的插值效果进行检验,以此确定最佳插值方案,分析研究区域的降水空间分布特征。[结果]顾及地形因素的协同克里金插值效果最佳,并能真实地反应研究区域的降水空间分布特征,普通克里金法次之,反距离加权法和径向基函数法较差。对插值结果的进一步分析显示,该研究区域降水呈现明显的纬度地带性分布特征,且降水受地形、地貌等因素影响较大。[结论]顾及地形因素的协同克里金插值法效果最优,适用于该区域。 相似文献
17.
分布式水文模型建立在物理机理的基础上,能够较好地反映流域下垫面条件的影响,能模拟计算降雨产汇流的过程,分析时空分布特性,是目前水文科学研究中的一个重要发展方向。流域水文模拟从模拟的侧重点上可以划分为降雨径流模拟、地下水模拟、流域水循环综合模拟。从流域水资源管理的角度出发,分别介绍上述模型的总体结构、特点及适用领域等。 相似文献
18.
毛乌素沙地存在水资源短缺和生态环境脆弱的问题，探究其蒸散发时空格局可为区域水资源开发利用和生态环境保护提供依据。基于2000—2019年MOD16数据分析毛乌素沙地蒸散发（evapotranspiration，ET）年际变化及其空间分布特征，选取气象数据、植被指数和土地利用/土地覆盖数据，通过趋势和相关系数分析其对ET的影响。结果表明：毛乌素沙地ET在空间上表现出显著的区域差异性，整体呈西北低、东南高的分布规律，2000—2019年的均值为258.8 mm；2000—2019年毛乌素沙地ET呈快速上升趋势，平均变化速率为6.87 mm·a-1； ET与降水量相关系数为0.74，与气温无明显相关性，不同土地利用/覆被的ET存在明显差异性；ET与归一化植被指数（normalized difference vegetation index，NDVI）空间分布和年际变化曲线一致，二者全区域决定系数为0.628 8。在降水量、土地利用/覆被、NDVI等因素共同影响下，2000—2019年毛乌素沙地ET明显增加，其中降水量是毛乌素沙地气候条件的主要因素，NDVI是影响同一时期ET的重要因素。该研究为毛乌素沙地生态水源涵养与保护提供理论基础和科学依据，对研究区落实水资源管理制度和生态环境保护政策具有重要的指导意义。 相似文献
19.
冬小麦-夏玉米轮作区土壤养分时空变化特征 总被引：8，自引：2，他引：6
【目的】研究冬小麦-夏玉米轮作区土壤养分的时间和空间变化规律以及多年轮作对土壤养分的影响。【方法】以国家精准农业示范研究基地为例,利用GIS技术和地统计学方法,结合《北京土壤养分分等定级标准》,分析冬小麦-夏玉米轮作区土壤养分时空变异特征。【结果】从2000—2007年,研究区严重缺乏磷、钾养分,且含量等级呈下降趋势;土壤全氮含量虽在部分区域偏高,但盈亏等级也呈下降趋势;有机质含量略微增加,处于平衡状态。不同年度的各土壤养分的变异系数范围为11.00%—51.71%,属于中等程度的变异。随着时间的推移,有效磷、有机质、全氮和碱解氮空间分布稳定。速效钾在2001年空间分布规律与2000年和2007年不同,但2000年和2007年空间分布一致,说明土壤速效钾空间分布也具有一定的稳定性。【结论】整体上来说,研究区南部和东北部土壤养分含量偏高,中部含量偏低。当田块土壤物理特性有大的变动时,土壤养分的空间结构特征会受到一定影响;但当长时间田块耕作管理相对一致时,结构性因素（尤其土壤特性、气候）起主要作用。 相似文献
20.
目的 研究在均衡施肥模式下,双山农场2012—2016年间土壤速效养分的时空变异特征,分析施肥管理、轮作模式等人为因素和气象、地形等自然因素对速效养分变化的影响,该研究成果可为土壤速效养分管理和作物变量施肥提供参考依据。方法 以双山基地农场为例,通过时间序列HJ-1 CCD遥感数据和作物模型WOFOST反演得到土壤速效养分。基于以上土壤速效养分数据在不同时间尺度（年际间和生长季内）和不同空间尺度（农场尺度和田块尺度）上的速效养分时空变异分析。利用土壤速效养分分级图来定性分析养分在5年内的空间变异特征;选取相应的统计参量对土壤速效养分的平均含量和变异性进行定量分析;利用线性回归来分析速效养分的变化量与初始含量的关系;以及养分变化曲线图分析速效养分的时间变化特征。结果 在均衡的农田施肥管理模式下,2012—2016年农场的土壤速效氮（AN）、速效磷（AP）和速效钾（AK）含量平均值变化不大,速效养分高值和低值都在向中间值靠拢,分别集中于280—360 mg·kg -1、38—42 mg·kg -1和160—200 mg·kg -1,该部分面积比例分别增加18.5%、23.1%和23.8%,养分含量整体呈现均一化特征。AN、AP和AK的变异系数分别从2012年的0.314、0.112和0.257变为2016年的0.131、0.034和0.098,速效养分分布的空间差异性在减弱。AN,AP变化量均与初始值呈现极显著的负相关,R 2分别为0.839和0.882,AK的R 2为0.569,其相关性较弱与土壤中的速效钾本身不稳定有关。通过相邻地块的养分变化分析可知,田块尺度上的土壤速效养分也表现出明显的均一化特征,轮作模式是影响田块间养分变化差异的主要因素,对于轮作模式完全相反的#1和#2田块,人工施肥决定了田块内养分变化的总体趋势,对于豆科作物,固氮作用对土壤速效氮的含量变化作用明显。温度升高在一定程度上会促进作物对养分的吸收,但这种影响不足以改变养分变化的总体趋势。土壤的淋洗对养分的空间变异起到决定性作用,特别是强度较大的降水。降水对养分空间变异的影响在地形差异较大的区域,表现得更加明显。 结论 农田的施肥管理和作物轮作模式是土壤速效养分变化的主导因素;其次是气候因素,雨水对土地的淋洗会导致土壤速效养分的流失和下降,该作用在地形差异较大的地区更加明显;速效养分的变化量与养分初始含量关系显著;温度的升高会促进土壤速效养分的降低,其影响力小于降水。以上变化规律均可纳入后期速效养分的预测研究中,对这些影响因子赋予不同的权值,进行预测模型的构建。以期对作物年际间和生长季内的速效养分的变化进行实时动态监测。 相似文献