Effects of fertilization on young forest growth and leaf physiological characteristics of Toona ciliata var. pubescens

Abstract

In order to explore the response of the precious tree species Toonaciliate var. pubescens to different amounts of different fertilizers, the young forest of T. ciliate var. pubescens was taken as the research object. A random block design was used to analyze the effects of fertilization on the growth, leaf nutrients and physiology of young forest of T. ciliate var. pubescens, and three fertilization levels (high, medium and low) were set, including nitrogenous fertilizer (N), phosphate fertilizer (P), compound fertilizer (CF) and slow-release fertilizer (SRF). The results were as follows: (1) Fertilization could promote the height and diameter at breast height (DBH) growth, and the effects of nitrogenous fertilizer and compound fertilizer were more obvious. The average tree height, average DBH and average volume of 4-year old tree with nitrogenous fertilizer increased by 15.0%, 21.9% and 67.5% compared with CK (no fertilizer), respectively, and the annual average growth of DBH under low nitrogenous fertilizer (N1) treatment was the highest (2.99 cm). Compared with CK, the average tree height, average DBH and average volume of compound fertilizer were increased by 16.7%, 19.2% and 54.3%, respectively. High slow-release fertilizer (SRF3) and low phosphate (P1) had the largest annual increases in tree height and DBH (1.96 m and 2.33 cm) in the 4th year, respectively. (2) Fertilization significantly increased chlorophyll content and non-structural carbohydrate content in leaves of T. ciliate var. pubescens, nitrogenous fertilizer significantly promoted the synthesis of soluble sugar and phosphate fertilizer significantly promoted the synthesis of starch. (3) N1 and phosphate fertilizer significantly promote the increase of N and P contents, respectively, and phosphate fertilizer, compound fertilizer and nitrogenous fertilizer significantly increased K content in leaves. (4) The principal component analysis showed that the effect of fertilizer to promote growth was nitrogenous fertilizer>compound fertilizer>phosphate fertilizer>slow-release fertilizer>no fertilizer. Among them, N1, i.e. 100 g·plant-1·year-1, had the highest comprehensive evaluation value. Comprehensive fertilization cost and benefit, nitrogenous fertilizer or compound fertilizer can effectively promote the growth and development of T. ciliate var. pubescens young forest. It is recommended to apply 100 g nitrogenous fertilizer per plant per year in young forest stage. The results can provide a reference for the forest nutrient management in the early stage of afforestation.

Keywords

• toona ciliate var. pubescens
• young forest
• fertilization
• growth
• physiology