Abstract: Non-point source pollution has remarkable spatial variability, and the pollutants coming from several landscape units usually account for the majority of the pollutant loads in a catchment. These landscape units are the critical non-point source pollution areas (CSAs). How to identify the critical source areas of pollutant losses from agricultural lands is very important for the control of agricultural non-point source pollution. The approaches such as export coefficient, pollution index, and non-point source pollution model are adopted to identify the CSAs at field and catchment scales. This paper mainly described the applicability and the problems of the approaches with systematic analysis, and, aiming at the present research characteristics and existing problems, offered the concrete proposals and expectations for the future study, such as field observation, combination of existing identification methods, methods for multi-angle identification, and application and integration of new technologies.

Key words: photoperiod, dormancy induction, peach, photosystem, chlorophyll fluorescence transient kinetics.