Soil quality assessment indicators and their spatial-temporal variability

The concept of soil quality was reviewed and the method of selecting soil quality assessment indicators discussed.Soil quality assessment is based on soil function with different criteria in accordance with soil types.Major emphasis is on the use of soil chemical and physical properties as indicators of soil quality.At present,investigations on soil biological parameters are only gaining grounds.Soil bio-indicators are showing great potential to become early warning and sensitive indicators of soil stree or perturbation.Research‘protocol’of spatial variability in soil quality is presented and exiting problems discussed.Finally,future research direction on soil quality spatial variability at home and abroad is forecasted.