施肥和透光抚育对红皮云杉幼龄人工林林木生长的影响

Effects of Fertilization and Light-Felling on Growth of Juvenile Picea koraiensis Plantation

为解决云杉(Picea)属树种早期生长缓慢影响大径材用材林的培育周期,可通过合理施肥和抚育措施结合处理,促进树高生长和地径增加。以落叶松林下红皮云杉(Picea koraiensis)10年生人工幼龄林木为研究对象,随机设置12块10 m×10 m的固定样地,肥料类型选择氮(N-尿素)、氮磷(NP-尿素+过磷酸钙)、氮磷钾(NPK-尿素+过磷酸钙+磷酸钾)。设置2种施肥时间,1)生长季前中后期施肥。每年在生长季初(5月中旬)、中(7月中旬)、后期(8月中旬)施肥3次,连续重复施肥4 a;2)生长季前中末期施肥。每年在生长季初(5月中旬)、中(7月中旬)、末期(9月中旬)施肥3次,连续重复施肥4 a。透光抚育设置,施肥一个生长季后对上层落叶松林木进行生长伐,抚育后林分郁闭度为0.6。通过研究施肥和透光抚育对林木生长的影响,旨在开发促进红皮云杉幼树生长的施肥管理技术,以缩短幼龄林生长周期。施NPK肥促进红皮云杉幼树树高和地径生长的效果好于只施单一肥料或氮磷2种肥料的混合肥。生长季前中末期施加NPK肥处理的树高、地径年生长量比生长季前中后期施加NPK肥的处理分别高41.11%和49.81%。透光抚育后不同年份之间林木的树高年生长量差异不显著,地径年生长量差异显著,3个生长季后树高和地径的年生长量与抚育前相比差异不显著。生长季前中后期施肥结合透光抚育处理2个生长季后树高和地径的年生长量与对照差异显著,3个生长季后只有地径的年生长量与对照差异显著。生长季前中末期施氮磷钾肥处理(NPK2)结合透光抚育处理3个生长季后,地径年生长量分别高出对照和生长季前中后期施氮磷钾肥(NPK1)结合透光抚育的处理153.16%和10.31%。施肥与透光抚育结合处理可以提高红皮云杉地径的年生长量,在连续施肥4 a时达到显著水平,生长季前中末期施肥效果好于前中后期施肥。研究结果为解决林下造林红皮云杉人工林木幼龄期生长缓慢、缩短红皮云杉大径材用材林培育周期奠定了基础。

The period of cultivation of large-diameter timber stands is affected by the relatively slow initial growth of Picea species.The combination of fertilization and nurturing measures can promote the growth of tree height and ground diameter.In this paper,12 fixed plots of 10 m×10 m were randomly set up in a larch understory with 10 a juvenile Picea koraiensis plantations as the study subjects.Fertilizer types were selected as N(N-urea),NP(NP-urea+superphosphate),NPK(NPK-urea+superphosphate+potassium phosphate).Two types of fertilization time were set:(1)pre-middle-late growing seasons fertilization:fertilizer was applied per year at the beginning(mid-May),middle(mid-July),and late(mid-August)of the growing season,with fertilization repeated for four consecutive years.(2)Pre-middle-end growing seasons fertilization:fertilizer was applied per year at the beginning(mid-May),middle(mid-July)and end(mid-September)of the growing season,with fertilization repeated for four consecutive years.Light-felling was set as follows,after one growing season of fertilization,accretion cutting the upper larch trees,and the stand density was 0.6 after tending.By studying the effects of fertilization and light-felling on the growth of trees,the aim was to develop fertilization management techniques to promote the growth of juvenile P.koraiensis,so as to shorten the growth cycle of young plantation.The effect of applying NPK fertilizer on promoting the height and diameter growth of juvenile P.koraiensis was better than applying only a single fertilizer or a mixture of nitrogen and phosphorus fertilizers.The annual tree height and ground diameter growth were 41.11%and 49.81%higher in the treatments NPK fertilizer applied pre-mid-end growing seasons than those treated with NPK in the pre-mid-late growing seasons.After light-felling,the annual growth of tree height between different years was not significantly different,but that of the ground diameter was significantly different.The annual growth of tree height and ground diameter after three growing seasons were not significantly different from that before light-felling.By combining fertilizer application in the pre-middle-late growing seasons with light-felling treatments,the annual growth of tree height and ground diameter were significantly different from the control group after two growing seasons,only the annual growth of ground diameter was significantly different from the control group after three growing seasons.After three growing seasons of nitrogen,phosphorus and potassium fertilizers(NPK2)combined with light-felling in the pre-mid-end of growing seasons,the annual growth of ground diameter was 153.16%and 10.31%higher than that of the control and pre-middle-late of growing seasons NPK fertilizers(NPK1)combined with light-felling.The combination of fertilization and light-felling treatments can increase the annual growth of P.koraiensis ground diameters,reaching a significant level at four consecutive years of fertilization.Fertilizer application at the pre-mid-end stages of the growing season is more effective than at pre-mid-late stages.The research provides a basis for solving the problem of slow growth of P.koraiensis plantation at a young age and shortening the cultivation period of large-diameter timber plantation of P.koraiensis.