GEOCHEMICAL EVALUATION OF LAND QUALITY AND DEVELOPMENT SUGGESTION OF LAND IN HAILUN CITY, HEILONGJIANG PROVINCE

Based on the data of soil heavy metals and nutrients obtained from the 1:10 000 land quality geochemical survey in Changfa Town of Hailun City, referring to the Soil Environmental Quality Standard (GB15618-2018) and Code for Land Quality Geochemical Evaluation (DZ/T0295-2016), the authors use single index evaluation method to evaluate the soil nutrients and environment quality in the study area, on this basis, making a superposition analysis of the two to determine the comprehensive geochemical grades of land quality. The results show that the soil nutrients are mainly rich and relatively rich, accounting for 37.49% and 62.22% of the total area respectively, lack of B and Mo; 99.94% of the land is risk-free (first grade) and 0.06% is risk-controllable (second grade) which is mainly affected by Cd and Hg. The comprehensive geochemical evaluation results of land quality indicate that the study area is dominated by first-grade(fine) land, accounting for 99.66% of the total evaluation area. The Se-rich land area in Changfa Town is 19.25 km², with the soil Se content of 0.4×10^-6-1.4×10^-6, averagely 0.44×10^-6. The cultivated land of 138.44 km², conforming to green food production area, occupies 99.84% of the survey area, among which the green Se-rich and green food production areas cover 18.53 km² and 119.91 km² respectively.