An approach to extrapolate categorical agricultural soil data to nonmapped areas using majority vote

Soil maps are indispensable base material for planning processes and risk analyses. For many studies, however, area‐wide uniformly scaled soil maps are not available. Our objective was to develop a GIS‐based method for providing information for NoData areas of the Medium‐Scale Agricultural Site Mapping (MMK). NoData areas represent nonagricultural zones, in this case especially forests. A grid‐based methodology for extrapolating soil mapping units of agricultural areas to the entire landscape was developed and tested in Mecklenburg–Western Pomerania (total area 23,170 km²). The principle of the extrapolation method is based on a statistical neighborhood analysis implemented by the moving‐window technology considering selected site features as geology, altitude, and relief energy. Results were illustrated exemplarily for soil‐moisture conditions, which are expressed as “hydromorphy association types”. Four different indicators were derived to ensure a spatially differentiated evaluation of the extrapolation quality. The precision with which it is possible to extrapolate already mapped MMK units in terms of the hydromorphy association type was used to validate the extrapolation method. Evaluation of the results was based on the percentage of Correctly Extrapolated Pixels (CEP), which were derived from a confusion matrix. The percentage of CEP was 26% when the 15 single classes of the hydromorphy association type were considered separately. The percentage of CEP rose up to 65% after grouping the hydromorphy association types into three practically combined categories. It could be demonstrated that the extrapolation technique applied represented an objective and relatively fast and cost‐effective method to obtain an area‐wide MMK mapping.     

Bodenvergesellschaftungen nach der mittelmassstäbigen landwirtschaftlichen standortkartierung (MMK)

Nach den Leitbodenformen, ggf. auch nach charakteristischen Begleitbodenformen der Standortregionaltypen der Mittelmaßstäbigen Landwirtschaftlichen Standortkartierung (MMK) werden Bodenvergesellschaftungen definiert und systematisiert. Diese Systematik spiegelt die pedogenetischen Bedingungen für die Ausbildung des Bodenmosaiks wider, und zwar zum einen durch den Hydromorphieeinfluß und zum anderen durch subtrat‐ und/oder klimabedingte Modifikationen der Bodenbildung. Stark durch Wassererosion geprägte Bodenvergesellschaftungen werden gesondert hervorgehoben.

Im Regelfall kennzeichnen zwei bis drei bodensystematische Einheiten (Bodentypen, Bodensubtypen) die Bodenvergesellschaftungen. Deren Darstellung erfolgt jeweils gesondert für das Pleistozängebiet und den Sandlößgürtel (D‐Standorte), die Auen (Al‐Standorte), das Lößgebiet (Lö‐Standorte) und das Berg‐ und Hügelland (V‐Standorte). Eine weitere Zusammenfassung der Bodenvergesellschaftungen liegt tabellarisch vor.     

古蔺县近50年来降水序列趋势分析

以1960—2009年古蔺县降水量观测资料为基础,运用数理统计、非参数Mann-Kendall(MK)和改进的非参数Mann-Kendall(MMK)趋势检验等方法分析了该县降水系列的年际、年内变化趋势,并通过比较MK和MMK趋势检验法的计算结果来分析自相关性对降水序列趋势显著性的影响。结果表明:古蔺县近50年来年降水量总体在均值附近上下波动,呈缓慢下降趋势;年内降水量分配受季节影响显著,春夏两季降水量呈上升趋势,秋冬两季降水量呈下降趋势;各降水序列进行趋势检验时,无论考虑自相关性与否,均未通过5%显著性水平;在使用MK方法时,古蔺县年降水序列和季降水序列均存在负向的自相关性,导致在同水平显著程度上低估了序列的趋势显著性。