Spatial Differentiation of Ecological Stoichiometry of Nitrogen and Phosphorus in Mollic Epipedon of China

Nitrogen (N) and phosphorus (P) are essential elements for crop growth. The study on the spatial differentiation characteristics of soil N and P can provide a theoretical basis for regional fertilization as well as prevention and control of agricultural surface pollution. Taking the typical mollic epipedon area in Northeast China as study area, using the geostatistical model and 3S technology (Remote Sensing, RS; Geography information systems, GIS; and Global positioning systems, GPS), the spatial variation and influencing factors of N and P ecological stoichiometry in the surface soil (0-20 cm) were studied with 1,057 samples by five-point soil sampling method. The outcomes of the study showed that the average total nitrogen (TN), total phosphorus (TP), and N/P ratio were 1.88 g/kg, 0.276 g/kg, and 6.81, respectively. The degree of spatial variation is moderate, and structural factors such as topography and soil parent material are the main factors affecting the spatial variation of soil TN, TP content, and N/P ratio. Vegetation primarily affects the soil TN, TP contents, and N/P specific spatial variation. Soil TN and TP contents showed a downward trend from the northeast to the southwest region of the study. Different approaches of balanced fertilization, soil and water conservation, and reasonable spatial allocation are beneficial to improving the balance of soil N and P in the typical mollic epipedon area of Northeast China.