Authors : Yong Jiang , Qi Li and Wenju Liang
Abstract: Aimed to have a rational soil management of the cultivated fields in Sujiatun District, Shenyang, Liaoning Province of China, 358 soil samples (0-20 cm) were collected from the same sampling sites of the District in both 1980 and 2000, with each sample representing 100-120 ha of cultivated fields and the spatiotemporal variability of their Soil Organic Matter (SOM), available phosphorus (AP) and potassium (AK) over the two decades was investigated by using geostatistics and geographic information system. In both 1980 and 2000, the SOM and AK fitted normal distribution, AP fitted lognormal distribution and spherical models for semivariogram fitted all the variables. Semivariograms indicated that the SOM changed from a moderately spatial dependence in 1980 to a strongly ones in 2000. The AP was a little more, while the AK was a little less spatially dependent in 2000 than in 1980. The maps obtained with kriging showed a decreasing trend for SOM and AK and an increasing trend for AP over 20-year period. The spatiotemporal variability of these parameters might be affected by both intrinsic (soil formation factors) and extrinsic factors (soil management practices) and the input of chemical and organic fertilizers was thought to be one of the key factors affected the spatiotemporal variability of test soil properties. It was suggested that P application induced the increase of the spatial heterogeneity of AP in test area, while the low input of organic fertilizer and K made SOM and AK more homogeneous.
Yong Jiang , Qi Li and Wenju Liang , 2006. Spatiotemporal Variability of Soil Organic Matter, Phosphorus and Potassium in Cultivated Fields of Southern Shenyang, China. Agricultural Journal, 1: 149-155.