关键词: 黑芝麻, 黑芝麻, 氮肥用量, 产量

Abstract: For solving the problems of monotonous landscape color in urban green space, unreasonable allocation of colorful plants and so on, based on the detailed investigation of colored-leaf tree species resources of urban green space in Lanzhou, taking 21 main kinds of colored tree species as the research objection in Lanzhou in recent years, detailed observation and record were carried out on the ornamental characteristics and ecological habits. Meanwhile, 13 important evaluation factors were selected and a comprehensive evaluation model of colored-leaf tree species in urban green space were established, comprehensive evaluation of ornamental value was carried out by using the method of analytic hierarchy process, classification of ornamental value was studied according to evaluation results. The results showed: (1) among 13 evaluation factors, the ornamental value contribution of factor P11(cold-resistant), P7(anti-drought), P12(color duration) and P13 (anti-pest)were bigger than others; (2) the comprehensive evaluation grade could be divided into three, there were gradeⅠ, gradeⅡ and grade Ⅲ respectively. Among them, there were 4 tree species for gradeⅠ, 13 species for gradeⅡ and 4 species for grade Ⅲ. (3)The trees of gradeⅠ had high ornamental value and suggested to be the first selection tree species in Lanzhou urban green place planning, the trees of gradeⅡ had higher ornamental value and suggested to use largely in Lanzhou urban green place planning, the trees of grade Ⅲ had ordinary ornamental value and suggested to use selectively according to spot condition.