NO3-N concentration in irrigation wells was measured. Geostatistical method combined with GIS
technique was used to analyze the spatio-temporal distribution of groundwater NO3-N concentrations in
Huantai County. Land use type and irrigation water resource were combined with the variation of NO3-N
concentrations by statistical approach to investigate the relationship between them. The distribution
map showed that the percentages of area increased by 13.06%, 14.37%, 12.23% and 3.85% for that had
nitrate concentrations of 10–15, 15–20, 20–30 mg L1 and greater than 30 mg L1 for shallow
groundwater, respectively, while decreased by 28.87% and 14.63% for 0–5 and 5–10 mg L1. In the wellirrigated
field, the NO3-N concentrations in shallow groundwater had increased for vegetables, wheat–
vegetables and wheat–maize rotations. In contrast, fast-growing tree system could act as a buffer to
retain shallow groundwater nitrate content which resulted in reduced NO3-N concentrations. Under the
same land use condition, irrigation with sewage, or well and sewage by turns would both enormously
add nitrate to groundwater.