1) adhere to the principle of combining research and evaluation closely. Research results are the basis of scientific evaluation. Agricultural geo-environmental assessment must extensively absorb and make use of multidisciplinary investigation results, fully tap the investigation results and literature information, deeply understand the characteristics of the research object, and analyze the relationship between regional element distribution patterns, anomalies and geological background (soil-forming parent material), soil properties and environmental pollution. According to the actual needs of assessment and zoning, the assessment research work is deployed, and the abnormal reasons and pollutant sources are analyzed in combination with the results of anomaly verification and investigation in the demonstration area, and the migration, circulation, absorption and accumulation of pollutants in the soil-water-plant (agricultural products) system and its main influencing factors are studied.
2) Adhere to the scientific principle of evaluation. Combined with agricultural product safety investigation, anomaly verification and demonstration area work, grasp typical anomalies, representative geological environment units, important crops or famous agricultural products, deeply study the migration and absorption laws of elements and pollutants in soil-plant system and their relationship with agricultural product safety, and combine the relationship model under specific conditions with the study of regional statistical laws to guide regional environmental quality evaluation and local environmental quality standard formulation.
3) Follow the evaluation workflow from simple to complex and from low to high. Study and establish a method system from single index to multi-index, single factor to multi-factor, from single factor status evaluation of soil and water with mature methods and standards to exploratory comprehensive evaluation and prediction evaluation.
4) Make full use of new methods and technologies. Facing the massive data of agricultural geological environment investigation and the complex factors that need to be considered in comprehensive evaluation planning, it is a technical way to realize agricultural geological environment evaluation to give full play to the advantages of computer technology in multi-information comprehensive analysis and spatial superposition processing. For example, the geological model of crop suitability needs to consider environmental factors and indicators such as landform conditions, bedrock geology, soil type, structure and its physical and chemical properties, hydrogeological conditions, climate factors, and element geochemical characteristics. Geographic information system (GIS) makes it possible to process this kind of multi-information and analyze the spatial map.