河北省遵化平原土壤养分的时空变异特征——变异函数与Kriging插值分析

Abstract

运用地统计学 ,结合 GIS研究了 2 0年前后河北省遵化县 （市 ）土壤表层 （ 0～ 2 0 cm）速效钾、速效磷和有机质 3种养分的时空变异规律。配对样本的 t检验以及 kriging插值的结果表明 ,1 999年土壤速效钾、速效磷和有机质的含量比 1 980年有一定提高。 3种养分的空间分布特征也不同程度地发生了变化。有机质的空间分布特征变化较大 ,其块金值 （ Nugget）与基台值（ Sill）之比从 1 980年的 60 %下降到 1 999年的 32 .3% ,变程也由 4.8km变为 2 .7km。速效钾和速效磷的块金值与基台值之比也有一定变化 ,但变程没有太大改变。人类的施肥、耕作措施的改变及土地利用变化是引起土壤养分变化的主要原因。

Geostatistics has proven to be useful for characterizing and mapping spatial variability of soil properties, however, most of the previous geostatistical studies were focused on data at small scale. With the development of GIS and GPS, geostatistics and GIS are becoming indispensable in characterizing and summarizing spatial information in large regions to provide quantitative support to decision and policy making for soil, agricultural and natural resources management. In this paper, we applied geostatistics combined with GIS to analyze the spatio-temporal variabilities of the available potassium, available phosphorus and organic matter in soil surface (0~20 cm) in Zunhua county (municipality) of Hebei province over 20 years from 1980 to 1999. Results showed the average content of the available potassium, available phosphorus and organic matter in soil surface in 1980 was 77.78 mg/kg, 19.46 mg/kg, 1.14%, respectively; and that in 1999 was 90.12 mg/kg, 25.7 mg/kg, 1.54%, respectively. Paired samples t test of soil nutrients and the results estimated by block kriging indicated the content of the available potassium, available phosphorus and organic matter in 1999 was significantly higher than that in 1980. The ratio of nugget to sill of the three soil nutrients varied from 32.3% to 60%, indicating the spatial correlation of the three tested soil nutrients at this large scale was moderately dependent. The ratio of nugget to sill of available potassium was 56.5% in 1980 and 41.1% in 1999, that of the available phosphorus was 45.5% in 1980 and increased to 54.1% in 1999. The ratio of organic matter changed considerably from 60% in 1980 to 32.3% in 1999. The range of the available potassium and available phosphorus between the year of 1980 and 1999 was almost the same, however, the range of organic matter was from 4.8 km in 1980 to 2.7 km in 1999. The improvement of the available potassium and available phosphorus in soil was mainly contributed to the more application of fertilizers, and the content of organic matter was affected by the changes of tillage and land use, which also altered the spatial distribution of soil nutrients to different degrees over the past 20 years.