典型黑土坡面速效钾空间分布特征研究

The Spatial Distribution of Soil Available Potassium on Typical Slope Farmland in Black Soil of Northeast China

分层采集31个典型黑土剖面(0~60 cm),155个土壤样品,结合经典统计学和地统计学分析方法,研究速效钾(AK)立体空间分布规律。0~20 cm土层AK变程最大(280 m),20~40 cm土层变程最小(32 m),主要受结构因子影响(如:气候、地形、母质等),属于强度空间自相关。受光照、地形、侵蚀、入渗、含K矿物、作物生长等因子影响,水平方向西南朝向坡面AK大于东北,南朝向大于北朝向;垂直方向AK先降低后升高,多数20~30 cm土层AK显著低于50~60 cm土层。土壤AK水平空间分异主要受地形、侵蚀、辐射等因子影响,垂直空间分异主要受施肥、渗透、作物生长等因子影响。尽管研究区土壤侵蚀比较严重,但是0~60 cm土层AK含量在相当长的时间内不会成为影响作物生长的限制因子。

Soil fertility is important not only at cultivation layer but also at high root density layer in farmland. The spatial variance of available potassium(AK) at high root density layer is helpful to evaluate fertility and increase crop yield. In this research, 155 soil samples were collected from 31 soil profiles(0- 60 cm) in a typical black soil of Northeastern China. Both traditional statistics and Geostatistical method were used to analyze the variability of AK at 0- 60 cm layers. The primary results showed that the range of AK was longer at 0- 20 cm(280 m) than at 20- 40 cm(32 m). AK in soil layers was mainly influenced by structure factors(e.g. climate, topography, parent material and so on), and belong to the intensity of spatial autocorrelation. AK was higher in west-south aspect than in north-east aspect and in south aspect than in north aspect of horizontal slope, which was influenced by solar radiation,topography, runoff, and so on. AK was significantly lower at 20- 30 cm depth than at 50- 60 cm depth of vertical slope, which was associated with infiltration, fertilization, crop growth, and so on. AK content of 0- 60 cm soil depth would not be a limited factor for crop growth in a long time, although soil erosion was serious currently in this region.