Investigating temporal and spatial patterns of cranberry yield in New Jersey fields

Cranberries are grown in sensitive wetland ecosystems and precision farming could be beneficial to reduce agro-chemical pollution and increase production without expanding area. Precision farming requires knowledge of the variation of yield within-fields but cranberry harvesting methods produce only one yield value per field unless an expensive pre-harvest berry count is done. Co-operatives and extension services have an important role in precision farming to: (1) determine important factors affecting yield patterns within a growing region and (2) identify fields that would benefit most from future intensive survey. This paper reports a study to investigate temporal and spatial patterns in useable and poor quality cranberry yield for the New Jersey (NJ), USA growing region. Principal components analysis indicated that mean growing season temperature is important for understanding temporal patterns in useable yield and maximum temperatures and precipitation for poor quality yield. Multiple linear regression showed that some cultivars were susceptible to disease and poor quality yield in years with high maximum growing season temperatures. Analysis of spatial patterns using area to area and area to point kriging, local cluster analysis and geographically weighted regression helped identify clusters of fields that were consistently yielding or alternated between high and low yielding. They also showed differences between owners and soil types particularly in hot or wet years showing the different response to soil types to weather and the potential for improvement in irrigation practices by some owners. The methods used should be useful for other growing regions and crops, particularly where there are no yield monitors.     

Self-organized origami

In origami, form follows the sequential spatial organization of folds. This requires continuous intervention and raises a natural question: Can origami arise through self-organization? We answer this affirmatively by examining the possible physical origin for the Miura-ori leaf-folding patterns that arise naturally in insect wings, leaves, and other laminae-like organelles. In particular, we point out examples where biaxial compression of an elastically supported thin film, such as that due to differential growth, shrinkage, desiccation, or thermal expansion, spontaneously generates these patterns, and we provide a simple theoretical explanation for their occurrence.     

气候变化下西北太平洋大海洋生态系海表面温度特征分析

气候变化和气候事件对海洋环境有着重大的影响,其影响存在着时空差异。研究以西北太平洋五个大型海洋生态系统(Large Marine Ecosystem,LME,包括西白令海,鄂霍茨克海,黑潮、亲潮以及日本海)的海表面温度(Sea surface temperature,SST)为研究对象,分析SST的随时空变化趋势及其与太平洋年代际振荡((Pacific Decadal Oscillation, PDO)和厄尔尼诺(El Ni?o)、拉尼娜(La Ni?a)事件的影响。研究发现,除了西白令海,其它四个大型海洋生态系统的SST都在1987年左右发生了急剧的上升,呈现出两个变化模态;将SST的长期变化趋势去除后,可以发现,五个LME的SST随着时间上下波动,并没有固定的周期性变化存在,但是与厄尔尼诺拉尼娜事件有着密切联系。水温的空间分布上看,各区域的SST都呈现由北向南逐渐增高的趋势,但是增温趋势不尽相同,在西白令海的整个区域SST都在升高,降温区域围绕在库页岛和日本的北海道附近,这其中相关机制有待后续进一步研究。     

中国农业发展的空间格局

我国农业发展水平在空间上呈现出较明显的区域性梯度分布格局，表现在：（１）宏观上，东部、中部和西部的发展速度不均衡，呈现东部快于中部，中部又快于西部的现象；（２）中观上，以城市为中心，同一区域不同地区的发展水平和农业生产结构随距城市的远近不同而变化；（３）微观上，农业发展水平随地理海拔高度的降低而提高的趋势。本文对我国２发展的空间格局形成的过程及原因进行了初步的分析。     

Relationship Between Six Years of Corn Yields and Terrain Attributes

Crop yield, soil properties, and erosion are strongly related to terrain attributes. The objectives of our study were to examine the relationship between six years of corn (Zea mays L.) yield data and relative elevation, slope, and curvature, and to develop a linear regression model to describe the spatial patterns of corn yield for a 16 ha field in central Iowa, USA. Corn grain yield was measured in six crop years, and relative elevation was measured using a kinematic global positioning system. Slope and curvature were then determined using digital terrain analysis. Our data showed that in the four years with less than normal growing season precipitation, corn yield was negatively correlated with relative elevation, slope, and curvature. In the two years with greater than normal precipitation, yield was positively correlated with relative elevation and slope. A multiple linear regression model based on relative elevation, slope, and curvature was developed that predicted 78% of the spatial variability of the average yield of the transect plots for the four dry years. This model also adequately identified the spatial patterns within the entire field for yield monitor data from 1997, which was one of the dry years. The relationship between terrain attributes and corn yield spatial patterns may provide opportunities for implementing site-specific management.     

黄地老虎越冬幼虫空间分布型及抽样技术研究

本文引用Iwao及Taylor等方法,研究了黄地老虎越冬幼虫在苜蓿田埂上的空间分布型。研究表明属均匀分布(α=-0.6256<0、β=1.9048>1),但在样方内的分布却是聚集的(b=1.7975>1)。这种分布是黄地老虎幼虫习性及其栖境所造成的。根据空间分布信息,计算出越冬幼虫调查所需样方面积为3.5—5平方米,比原规定的可少调查1.5—5平方米。黄地老虎(Agrotis segetum Schiff.)是新疆墨玉地区农作物的头号害虫。该虫多以老熟幼虫在苜蓿田埂中越冬,并以为害春播作物为最严重。当地主要依据调查越冬后的虫口密度,发出春季黄地老虎发生程度的中、长期予报。为了提高调查及予测的准确性,更好地指导防治,1981年我们对黄地老虎越冬幼虫的空间分布型及抽样调查作了初步研究,现将结果整理如下,供讨论。     

新巴尔虎草原火时空分布特征及对气象因子响应

目的草原火是草原生态系统重要的干扰因子,严重影响着系统的结构与功能。新巴尔虎草原草是我国重要的草原生态系统,随着极端气候事件的频发,加剧了该地区发生重特大草原火灾的可能性。本研究可为草原火的火险区划和管理提供科学依据。方法本研究基于遥感影像,借助地理信息系统和ENVI等软件,分析了2001—2016年新巴尔虎草原火时空特征,并结合气象数据,探讨草原过火面积对气象因子的响应特性。结果新巴尔虎草原火在时间和空间上呈现规律性分布。在时间上,过火面积年变化存周期性变化规律,2003年和2013年分别出现过火面积峰值,周期间隔10年;过火面积月变化差异明显,过火面积集中在4、5月和9、10月,时间对应研究区域火灾频发的春秋两季;在空间上,高频度火灾发生区域全部分布于国境线附近,越境火灾风险比较大。草原火过火面积与气象因子有着密切关系。在月平均气温为0~10 ℃、月总降水量在0~20 mm、月平均相对湿度40%以下及月平均风速大于5 m/s的区域最利于草原火灾的发生和蔓延。结论新巴尔虎草原火预防工作在区域上应集中在新巴尔虎草原西部、东南部和东北部地区,加强边境地区草原火的监测和管理。在时间上应关注每年4、5月和9、10月,特别是月平均气温0~10 ℃、月总降水量0~20 mm、月平均相对湿度40%以下及月平均风速大于5 m/s的地区。未来可从更长的时间和更广的空间尺度来对草原火的发生周期进行模拟和预测,更有效地探究野火的长期动态变化规律及其影响因素。      

Stochastic generation of regular distributions

A new class of models is proposed to describe the dynamic processes leading to the establishment of regular spatial patterns of structures in natural systems. Simple mathematical arguments are used to compute the saturating densities of the distributions, and these results are verified by computer simulation of model systems.     

苹果小绿叶蝉种群空间分布型研究

 小绿叶蝉在苹果园的种群空间分布型用Taylor幂法则,Iwao的m-m回归分析法进行分析,得出的结果均一致,即在小绿叶蝉发生活动期均为聚集分布,且随种群密度的变化,聚集和扩散趋势呈现出一定的规律性。     

光皮树幼林坡地土壤养分空间异质性和分布格局研究

采用地统计学的方法研究闽北光皮树幼林坡地土壤养分 （0~20cm） 的空间异质性和分布格局。结果表明：光皮树幼林坡地土壤有机质、易氧化有机碳、水解氮、有效磷和速效钾均有较好的空间自相关性,其自相关函数均为由正相关向负相关方向发展,拐点为35~66m;不同土壤养分的空间变异特征差异较大,易氧化有机碳的最佳拟合模型为指数模型,其余指标的最佳拟合模型均为高斯模型;除土壤有机质块金值/基台值的比值大于25%,呈现中等程度空间变异外,其余4个速效养分指标的块金值/基台值比值均小于25%,具有强烈的空间自相关,其空间变异主要由结构性变异引起,随机因素的影响较小;SOM、ROC和AP空间分布的连续性相对较好,其次为AN,AK的空间连续性较差,破碎化程度高,在小尺度上形成强烈的变异;坡面尺度土壤养分的空间异质性,不仅与坡位、微地形等环境因素有关,研究区采伐残余物输入的空间不均一性和炼山也可能对养分的空间变异有重要影响。     

A global map of human impact on marine ecosystems

The management and conservation of the world's oceans require synthesis of spatial data on the distribution and intensity of human activities and the overlap of their impacts on marine ecosystems. We developed an ecosystem-specific, multiscale spatial model to synthesize 17 global data sets of anthropogenic drivers of ecological change for 20 marine ecosystems. Our analysis indicates that no area is unaffected by human influence and that a large fraction (41%) is strongly affected by multiple drivers. However, large areas of relatively little human impact remain, particularly near the poles. The analytical process and resulting maps provide flexible tools for regional and global efforts to allocate conservation resources; to implement ecosystem-based management; and to inform marine spatial planning, education, and basic research.     

复杂性科学及其在生态系统研究中的应用

复杂性科学是一门新兴的交叉学科,主要研究复杂系统、复杂性及其方法论.生态系统是一个典型的复杂适应系统,处于混沌的边缘或临界态.内部作用是生态系统复杂化、有序化及自组织的主要推动力.复杂性科学应用于生态系统的研究,旨在更好地了解生物及其环境组分间的相互作用以及生态系统复杂性的动态特征与演化机制.本文综合国内外研究动态,介绍了复杂性的定义、复杂性科学的研究方法及在生态系统研究中的应用,并对一些存在的问题进行了探讨.     

三江平原地区土壤养分空间分布特征

[目的]全面、准确掌握三江平原地区土壤养分状况空间分布情况,为完善土壤养分管理制度与制定合理施肥措施提供初步的科学依据。[方法]基于网格法取样,用经典统计学和地统计学综合分析该区域土壤养分的空间变异特征。[结果]土壤养分指标的变异系数偏大,在20．17％～66．39％之间;在研究区域呈现一定的空间结构性,各养分指标的空间结构差别较大;空间自相关性明显,最佳拟合模型均为指数模型。块金值（C。）均较大,AN和AK的c。／c。＋C在25％～75％之间,其他指标的C。／Ｃ。＋Ｃ均〈25％。Kriging插值图表明,土壤养分的空间分布格局不同。[结论]从研究区域的整体养分状况来看,饶河县和宝清县交界处以及萝北县土壤养分状况较好．土壤OM、TN、rrP、AP含量均较高,而研究区域的西南部总体养分状况较差,OM、rr=N、_rK、AN、AP含量均处于较低的水平。地形条件、耕作年限是决定该区域土壤养分空间分布的关键因素。     

Formation and subdivision of deformation structures during plastic deformation

During plastic deformation of metals and alloys, dislocations arrange in ordered patterns. How and when these self-organization processes take place have remained elusive, because in situ observations have not been feasible. We present an x-ray diffraction method that provided data on the dynamics of individual, deeply embedded dislocation structures. During tensile deformation of pure copper, dislocation-free regions were identified. They showed an unexpected intermittent dynamics, for example, appearing and disappearing with proceeding deformation and even displaying transient splitting behavior. Insight into these processes is relevant for an understanding of the strength and work-hardening of deformed materials.     

番茄花叶病病株及传毒介体空间分布型研究

利用1998年广东省番茄花叶病春，秋两季的大田调查资料，采用各种分布型指数分析了病株的田间分布型和秋季植株传毒有翅蚜介体（Myzus persicae)的空间分布型。结果表明，番茄花叶病毒株在田间的分布型随时间的延续而变化，病株在流行初期呈随机分布，随后呈聚集分布，到后期则趋于均匀分布；秋季植株有翅蚜介体在田间的分布型以聚集分布为主，结合病株在病害流行前期有明显的聚集分布时期，推断有翅成蚜介体是秋季田疃病害扩展的有效媒介。     

Using low-cost geophysical survey to map soil properties and delineate management zones on grazed permanent pastures

Usually, soils utilised for livestock production have similar high spatial variability as those for agricultural or forest use. As a consequence, it is necessary to determine the spatial patterns of the main soil properties as the first stage to implement site-specific management. However, this has to be performed using an inexpensive technique because the profitability in these types of farm are very low, so owners need a cheap, effective, and reliable method to know which zones have similar production potential. Using soil apparent electrical conductivity (ECa) measurements, obtained with a contact sensor at many locations, as the basis to perform a directed soil sampling, 10 samples were taken at two depths (0–0.25 m and 0.25–0.50 m) in a 2.3 ha field in Évora (southern Portugal). Firstly, relationships between ECa and many soil properties were analysed using regression analysis. Six soil properties (clay, silt, fine sand, soil moisture content, pH, and cation exchange capacity) were significantly correlated with ECa. Consequently, spatial distributions of these variables were visualised using map algebra techniques. Later, a fuzzy clustering algorithm was utilised to delineate management zones, resulting in two subfields to be managed separately. Finally, a principal component analysis was conducted to analyse the influence of the soil properties and elevation on the soil variability. It was determined that elevation and clay were the most important contributing properties. Therefore, these can be regarded as key latent variables in this soil. Results showed that low-cost data based on ECa surveys can be used to implement site-specific management in soils with permanent pastures, such as those in the montado or dehesa ecosystems, in the southwest of the Iberian Peninsula.

     

种群空间格局研究的Z—V模型及其抽样设计方法

在定义种群聚集度指标Ｚ（Ｚ＝Ｖ／ｍ－１＋Ｖ）的基础上，本文提出一个种群空间格局研究的新模型：Ｚ—Ｖ模型（Ｚ＝Ａ＋ＢＶ），参数Ａ，Ｂ的９种不同组合型式分别揭示出不同的空间格局信息。经实例验证和比较表明，Ｚ—Ｖ模型具有更广泛的适用性和较高的可靠性，能客观地反映出种群空间格局的本质特征。基于Ｚ—Ｖ模型，文中还推导出了简单随机抽样确定理论抽样数和最适样方大小的公式以及序贯抽样决策模型     

城市化流域生态系统服务价值时空分异特征及其对土地利用程度的响应

以南京市九乡河流域为研究区域,以2003与2009年2景QuickBird影像数据为基本信息源,应用空间自相关模型,结合GIS空间分析技术,定量探讨了城市化流域生态系统服务价值时空分异特征,以及土地利用程度对生态服务价值空间分异的影响.结果表明:2003-2009年,九乡河流域生态系统服务总价值减少了2.59％,而流域生态系统服务价值的空间聚集性增强;生态服务价值的高-高区域主要集中在流域上游,低-低区域主要集中在流域下游的仙林大学城一带;九乡河流域生态系统服务价值空间分异发生了明显变化,下游仙林大学城一带低-低分布区快速扩张,而高-高分布区仅在九乡河源头及下游的局部区域有所增加;流域生态服务价值空间自相关表现出明显的尺度效应,随着研究尺度增大,生态服务价值的空间自相关性逐渐增强;九乡河流域生态服务价值的空间分异及其变化主要是由土地开发利用引起,流域土地利用程度对生态服务价值存在明显的负效应.     

基于MCE-CA-Markov和InVEST模型的伊犁谷地碳储量时空演变及预测

陆地生态系统碳源与碳汇的变化与土地利用/覆被变化（LUCC）的演变密切相关,为探讨土地利用变化对陆地生态系统碳储量的影响机制,基于1980—2020年LUCC数据集,通过多评价准则（Multi-criteria evaluation,MCE）的元胞自动机（Cell automata,CA）和马尔科夫链（Markov chain）模型,模拟伊犁谷地2030年的LUCC时空动态,耦合InVEST模型探讨土地利用变化下伊犁谷地1980—2030年陆地生态系统碳储量的时空演变格局。结果表明,MCE-CA-Markov模型预测LUCC数据集与2000、2010年和2020年实际LUCC精度检验的Kappa系数分别为0.929 1、0.875 5和0.929 7,模型模拟普适性较高,可对后续碳储量时空演变格局进行精准评估。利用InVEST模型估算的伊犁谷地1980年总碳储量约为1 114.95 Tg,预计至2030年总碳储量呈逐期下降趋势,累计净减少65.94 Tg,其中林草地面积的退缩是致使碳储量下降的主导因素。伊犁谷地碳储量空间分布总体上表现为高值区域环绕低值区域,呈嵌套分布。碳密度的高值区域分布在南部和北部山区林草地,而低值区域仅集中在中部河谷平原附近。研究土地利用变化对陆地生态系统碳储量的影响可为研究区碳库管理提供数据支持,为制定碳固存和环境保护政策提供理论参考。