Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2019-09-11 Cooperative journals: 《干旱区地理》
Abstract：准确、高效地掌握草原土壤属性的空间分布能够为草地资源境管理提供基础信息和参考依据。相比于传统土壤调查方法，基于模糊逻辑的土壤—环境推理能够提高野外采样效率和预测制图精度，被广泛应用于数字土壤制图。但由于土壤自身的空间变异性及其与环境条件间的非线性，现有推理模型的稳定性较低，尚未在高寒草原区进行应用。选择新疆巴音布鲁克典型亚高山草原地区约4 km2区域为研究区，以高程、坡度、坡向、沿剖面曲率、沿等高线曲率、地形湿度指数6个地形因子为土壤环境因子，采用模糊[WTBX]C[WTBZ]均值聚类（Fuzzy C-means Clustering，FCM）方法对环境因子聚类，得到9个环境因子组合，并在隶属度值高的环境因子组合中心共设置18个典型点。运用土壤—环境推理方法模拟研究区表层土壤pH值空间分布，其变化范围在7.170~8.186之间。选取35个独立样本进行精度检验（均匀采样点16个，横截面采样点9个，垂直带采样点10个），模拟结果与实测值基本吻合，且基于模糊聚类和土壤—环境推理方法的模拟精度高于普通克里格法和反距离权重法。通过基于模糊逻辑和土壤—环境推理的数字土壤制图方法在小尺度区域的运用验证，结果表明基于典型点的采样方案能够快速、有效地对区域土壤属性进行空间模拟，该方法对于类似小尺度的研究区同样有效。
Subjects: Biology >> Botany >> Plant ecology, plant geography submitted time 2016-05-03
Abstract： Aims Shrub was an important vegetation type which maintained stability of ecosystem in arid and semiarid zones. This study investigated the typical shrub species of grassland in northern Xinjiang, and analyzed their carbon (C) and nitrogen (N) content features of the leaves, branches and stems, in order to accurately estimate the C and N pools of shrub steppe, and to provide basic data for C and N cycling study. Methods Leaves, branches and stems samples of 13 kinds of species were collected in northern Xinjiang. We determined C and N content of leaves, branches and stems. Important findings In northern Xinjiang, the typical shrub were Nitraria, Convolvulus tragacanthoides, Reaumuria songarica, Anabasis, Caragana, Ephedra, Calligonum mongolicum, Haloxylon, Spiraea hypericifolia, Krascheninnikovia, Nanophyton erinaceum, Kalidium and Salsola. These shrubs belong to the Rosaceae, Legumes, Ephedra, Tamaricaceae, Zygophyllaceae, Polygonaceae, Convolvulaceae and Chenopodiaceae . The size of the C content of different organs were stem (45.76 ± 3.43 )% > branch (44.27 ± 4.51)% > leaf (39.15 ± 5.91)% , the size of the N content of different organs were leaf (2.21 ± 0.59)% > branch (1.55 ± 0.44)% > stem (1.34 ± 0.35)% , the size of C: N of different organs were stem (36.74 ± 10.80) > branch (31.07 ± 10.43) > leaf (18.94 ± 5.82). The C、N content and C: N in the same organs of shrubs were significantly different among different families ( p < 0.05). C content of different organs of Rosaceae were significantly larger than the those of other subjects among different genus ( p < 0.05), N content of leaves and stems of Legume were significantly larger than those of other genus ( p < 0.05), N content of branches of Ephedra was significantly larger than other genus ( p < 0.05), the C: N of leaves and branches of Convolvulus tragacanthoides were significantly larger than those of the other genus ( p < 0.05), C: N of stems of Rosaceae were significantly larger than those of the other genus ( p < 0.05). The C content of aboveground was (43.77 ± 4.43)% , N content was (1.56 ± 0.45)% , C: N was (31.78 ± 10.12). The variation degree of C content was small, the average coefficient of variation was 10%, the average coefficient of variation of N content was 27% , the average coefficient of variation of C: N was 32%
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