科研之友
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摘要
Sulfur (S) has long been recognized as essential for plant metabolism, but over the last 30 years the increasing deficit of sulfur has become a problem all over the world. For this reason, more research should be devoted to determining the content and spatio-temporal variability of sulfur in relation to an improved management of this element. The aims of this study were to assess the spatio-temporal variability of soil sulfur forms and arylsulfatase activity against selected physicochemical properties on a plot scale. A grid soil sampling (10 x 10 m) was used to measure the spatial variation of soil properties across a 0.4 ha field. Soil samples were collected from the upper 27 cm of Luvisols at 50 location in April and August 2007 and 2008. The total (S-TOT), organic (S-ORG) and available (SO42--S) sulfur concentrations and arylsulfatase (AS) activity were analyzed. Additionally, total organic carbon (C-ORG), total nitrogen (N-TOT) concentrations, soil pH(KCl) as well as texture and water content were determined. The dataset was analyzed using classical statistical and geostatistical methods. Based on the analysis of variance, it was found that soil properties, except for CoRG, NTOT and pHR0, showed significant differences between the four sampling dates (Tukey's test, p < 0.05). Additionally, it was found that the temporal stability of the data set showed no clear time -associated shift based on Spearman's rank correlations coefficients. Relatively high degree of variability of the soil properties over time was also indicated by the mean relative differences (MRD). Generally, higher level of temporal stability was noted for the S forms and CoRG and Nror concentrations as compared to the AS activity. Among the studied propertieS, only AS activity at all sampling times and all of the S forms measured in August (except S-TOT in 2008 and SO42-S in 2007) revealed a spatial autocorrelation (Moran's 1). All the studied properties revealed a high contribution of nugget effect in sill (over 50%) or pure nugget effect Some properties revealed a moderate spatial structure (a nugget/sill ratio between 59.2 and 70.3%), whereas the concentration of SoRG measured in August 2008,and AS activity analyzed in 2008 were in the weak variability class. Only AS activity in 2007 showed a pure nugget effect The range of spatial autocorrelation calculated for the analyzed properties was between 20.0 and 34.0 m. Results of this study are essential to understand and predict the contribution of internal factors in the total variability of soil properties that can interfere with the influence of soil management practices. The spatio-temporal variability showed that the studied area was temporally unstable and more frequent sampling must be included in the sampling strategy in order to better understand whether the S forms and AS activity always show permanent spatial patterns in soil or whether they are more randomized.
- 出版日期2017-6-1
