Abstract: This paper put forward the method of fuzzy vector-Markov transfer matrix for ecological impact assessment.In this method,fuzzy vectors were used to discribe the condition of ecosystem,while Markov transfer matrixes were used to simulate the evolution tendency of ecosystem. So,both complexity and dynamics of ecosystem were taken into account.By this method,decision-makers were able to quantitatively assess the impact of development items on ecological environment.

Key words: wheat, critical nitrogen concentration, nitrogen diagnosis, nitrogen deficit model.