Study on the Spatial - Temporal Variability of Soil Nutrients during Winter Wheat Growth Season

The object of the study is to analyze the spatial-temporal variability of soil nutrients in the winter wheat growing season, and try to reveal the dynamic change of soil nutrients in winter wheat field. Measurements of soil nitrate nitrogen (NN), total nitrogen (TN) and available potassium (AK) in wheat field were taken at 132 sample points in April and June, 2006. Classical statistical method and geostatistics method were used in this study. The classical statistical analysis results indicate the average value of NN content decreased obviously from April to June, and the value of AK decreased slightly. But there were no change for the mean of TN content from April to June. All soil nutrient both in April and June were medium-degree variations. From the spatial distribution maps of soil variables, soil NN changed obviously on distribution between April and June. However, soil TN and AK had the similar spatial distribution that high in the northeast part and low in the southwest of the study field. In summary, winter wheat growth had great effect on soil NN content, whereas little effect on TN and AK. The differences of NN, TN and AK between June and April were negative in most areas and the absorptive capacity of winter wheat was different in different places.