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在位于俄克拉荷马州南部的原始草原上,沿一长200米的横断面每隔一米间距采集表层土样(0—15cm)。全部样品分属三个土系,并代表三种不同排水类型。测定每个样品的磁化率,并每隔一取样点轮流测定颗粒级配和有机质含量。沿断面每隔5米测量海拔高程。结果表明,岗、坡地处磁化率值较大,泄水区最小;磁化率与土样含砂量(母质)和土壤含水量(地形位置)相关。土壤含砂量与磁化率两者的断面分布图相似。粘粒含量和有机质含量沿断面略有增加,但与地形位置和土壤类型关系并不明显。由磁化率、砂粒含量和粉砂含量的半方差图确定相关域为59—64米,表明土壤界线约在60米和120米处。据此可粗略圈定排水良好和一般性排水与排水不良土壤的界线。用移动式裂窗法(数值法)检验界线位置。按土壤质地组成可大致划分三种不同土系的界线,但依据磁化率可获得更明确的界线。此外,磁化率还可反映土壤的排水条件。由于磁化率可在田间原位多点测定,并较测定质地要快得多,所以它在土壤调查领域中有广泛的应用前景。
On the pristine grasslands in southern Oklahoma, surface soil samples (0-15 cm) were taken at intervals of one meter along a 200-m long cross-section. All samples belong to three soil systems and represent three different drainage types. The magnetic susceptibility of each sample was determined and the particle gradation and organic matter content were determined in turn at each sampling point. Measure elevation above sea level every 5 meters along the section. The results show that the values of magnetic susceptibility at the hillside and slope are larger and the drainage area is the smallest. The magnetic susceptibility is related to the sand content (parent material) and soil water content (topographic location). Soil profiles of sand and magnetic susceptibility are similar for both sections. The content of clay and organic matter slightly increased along the cross section, but the relationship with the topography and soil type was not obvious. The correlation domain was determined to be 59-64 meters by the semi-variogram of magnetic susceptibility, sand content and silt content, indicating that the soil boundaries were about 60 and 120 meters apart. Based on this, we can roughly delineate the well-drained and general drainage and drainage of poor soil. Check the location of the boundary by the mobile cleft method (numerical method). According to the composition of soil texture can be roughly divided into three different lines of soil lines, but based on the magnetic susceptibility can get a more clear line. In addition, the magnetic susceptibility can also reflect soil drainage conditions. As the magnetic susceptibility can be measured in situ in situ and much faster than the measured texture, it has a wide range of applications in the field of soil investigation.