Study On The Growth And Soil Changes Of The Three Kinds Of Firs At Different Ages Fertilized With NPK+ Cu And Zn

Chinese fir is a pillar species in China's forestry.It also occupies an important position in national economy.However,due to years of continuous cultivation,and irrational forestry management measures,geographic recession of different degrees occurred to Chinese fir woodland.In order to solve the above problems,after simultaneous fertilization of NPK and Cu,Zn microelement fertilizer trials to the young forest,middle-aged forest and near-mature forest with different stand ages and stands,several intermittent researches were carried out,which provided a theoretical basis for the further development of fir production and research,as well as the sustainable management of forests.The study of this project set up three pilot sites,which were Maxi experimental plot,Daleikeng experimental plot and Yangkeng experimental plot in Yangkou state-owned forest farm.The woodland in each experimental plot was second-generation forest.Samples were gathered in each experimental plot and tests were analyzed respectively in December 2006,December 2007 and December 2008,December 2011.December 2013,the results were as follows:?(1)In 2007 and 2008,the fertilization of NPK+Cu+Zn had obvious effect on the average annual growth of fir breast-height diameter,tree height and stand volume;in 2011,the fertilization of NPK had more obvious effect on fir breast-height diameter and tree height,while the fertilization of NPK+Cu+Zn had the best effect on the average annual growth of stand volume;in 2013,the fertilization of NPK had obvious effect on fir breast-height diameter and tree height,while the fertilization of NPK+Cu+Zn had the best effect on the average annual growth of stand volume;(2)from 2007 to 2013,as for middle-aged forest,the fertilization of NPK had better effect on the growth of fir breast-height diameter and stand volume,while the fertilization of NPK+Zn had obvious effect on the growth of tree height.(3)In 2007 and 2008,the fertilization of PK had the best effect on the growth of fir breast-height diameter,the fertilization of PK+Cu+Zn had a better effect on the average growth of fir height,and the fertilization of PK+Zn had a significant effect on the growth of stand volume of fir in Yangkeng;in 2011,the fertilization of PK Cu+Zn had obvious effect on the growth of Chinese fir breast-height diameter,the fertilization of PK had significant effects on the growth of fir height,and the fertilization of PK+Zn had significant effects on the growth of stand volume of Chinese fir in Yangkeng;in 2013,the fertilization of PK had obvious effect on the growth of fir breast-height diameter and tree height,and the fertilization of PK+Zn had significant effect on the growth of stand volume of firs in Yangkeng.?(1)For the young forest,the natural moisture content of each fertilization treatment was higher than that of control treatment.Soil natural moisture content depended on precipitation,absorption of trees and moisture evaporation.It was closely related to the weather,while fertilization had little efect on natural water content.In the upper and lower soil layers,the total porosity of various fertilizer treatments was higher than control treatment.Fertilization had a significant effect on total porosity and the ratio of non-capillary porosity to the total porosity as time went by.?(1)In 2013,the organic matter content of woodland surface(0-20cm)increased,and effect was obvious when Cu and Zn fertilizers were added.When Cu and Zn microelement fertilizers were added to the young woodland,the organic matter in soil reduced firstly and then increased.The fertilization of NPK to young forest had an obvious effect on NPK content in soil.While the fertilization of NPK+Cu+Zn to young forest had an obvious effect on Cu and Zn content in soil.(2)In 2011,the organic matter content in woodland surface(0-20cm)increased compared to that of control treatment,and the effect was obvious when Zn fertilizer was added.The fertilization of NPK+Zn to middle-aged woodland soil had obvious impact on the NPK content in soil.In 2008,the fertilization of NPK+Zn had obvious effect on Cu and Zn content in soil.(3)In 2007,the organic matter content in woodland surface(20-40cm)increased,and the effect was obvious when PK+Cu+Zn fertilizers were added.The fertilization of PK to near-mature forest soil had obvious impact on NPK content in soil.The fertilization of PK+Cu+Zn to near-mature forest soil had obvious impact on Cu and Zn content in soil.