A Study on Seedling Grading of the Physic Nut
Botao Chen · Seed · 2008
The standard of seedling grading of the 6-month-old physic nut seedlings was discussed by using the methods of gradual cluster and average±standard deviation analysis.Height and ground diameter of seedlings were proposed as the main indexes of quality for seedling grading of the forestation of the oil-bearing energy forest of the physic nut,and the grading standards were produced for seedlings in Guizhou province.The seedlings with the height of 35 cm or above,the ground diameter of 1.8 cm or above were classified as grade Ⅰ,those with height lower than 35 cm but higher than or equal to 25 cm,ground diameter lower than 1.8 cm but higher than or equal to 1.4 cm were classified as grade Ⅱ,those with height lower than 25 cm and ground diameter lower than 1.4 cm were classified as grade Ⅲ.