Abstract: In the risk assessment of pests, both the community structure and the environmental factors should be considered at the same time, because of their mutu al effects on the outbreak of disaster pests. This paper established a comprehen sive assessment system, including 2 sub-systems, 5 respects, and 14 indices. In the meanwhile, risk assessment indices and experience formula were used to anal yze the risk degree of pests in Lycium barbarum fields under different manag ements. It was found that using risk assessment indices and experience formula c ould obtain similar results. In abandoned field, Aceria palida, Aphis sp., a nd Paratrioza sinica were the frequent disaster pests, Lema decempunctata, Neoceratitis asiatica, Jaapiella sp., and Phthorimaea sp. were the incidental disaster pests, and Psylliodes obscurofaciata and Phthorimaea sp. were general pests. In organic field, the frequent disaster pests were the same species as t hose in abandoned field, while P. indicus, Jaapiella sp. and Phthorimaea sp. were the incidental disaster pests. In chemical control field, A. palida, Aphis sp., P. sinica, and P. indicus were the frequent disaster pests , while Jaapiella sp. and Phthorimaea sp. were the incidental disaster p ests. Optimal 5 separations most fitted the division of pest sub-communities in L. barbarum fields, which were infancy period (from March 28 to April 15), outbreak Ⅰ period (from April 15 to July 18), dormancy period (from July 18 to September 8), outbreak Ⅱ period (from September 8 to October 15), and recession period (after October 15). The matrix of correlation coefficient showed that th e dynamics of pests in L. barbarum fields under different managements were s ignificantly correlated with each other, suggesting that the dynamics of pest po pulations was similar in different L. barbarum fields, which had two populat ion establishment stages and one exponential growth stage in every year. The opt imal controlling stages were from late infancy period to early and middle outbre ak Ⅰ periods, and from late dormancy period to early outbreak Ⅱ period, which were very critical for pest control.

Key words: runoff washout, water flow velocity, runoff kinetic energy, unit runoff energy consumption, hydrodynamics parameter.