Effects Of Fertilization On Growth,Nutrient Distribution And Root System Of Tilia Amurensis Rupr.Seedlings

In order to understand the effects of N,P and K application on the physiological growth,nutrient storage and root system of Tilia amurensis,we conducted the study in the nursery of Erdaohe Farm of Jiamusi City,Heilongjiang Province.We used the annual(S1-0)and biennial(S1-1)Tilia amurensis in as the research object,the field experiments were carried out with different fertilization methods,including conventional fertilization,autumn fertilization and formula fertilization.The NPK content and concentration,root morphology and the anatomical knot of 1st-order root growth physiology and field performance of Tilia amurensis after fertilization were measured.The following conclusions were obtained:(1)After fertilization in autumn,the growth of height and ground diameter of S1-0 in the current season and the second growth season after afforestation showed a significant difference(P<0.01).The biomass increased after fertilization,but there was no difference between the two years.The seedlings of S1-0 after fertilization in autumn had better field survival rate and field performance.To some extent,fertilization increased the specific leaf weight,chlorophyll,soluble protein content and SPAD value,but the promotion effect of autumn fertilization was more significant,The effect of applying fertilizer 2X(165mg/plant)in autumn is better(P<0.05).(2)After fertilization in autumn,the NPK concentration of the roots and the whole plant of S1-0 increased with the change of fertilization amount and showed a consistent rule:2X>1X>CF>CK(P<0.05).The total root length,total root surface area and total root volume of S1-0 showed CF>1X>2X>CK(P<0.05).The results showed that the V/R of 11st-order root was 2X>1X>CF>CK(P>0.05),The effect of applying fertilizer 2X(165mg/plant)in autumn is better.(3)For seedling height and ground diameter,reasonable proportion treatment 10(N2P2K3)could significantly promote the radial and lateral growth of S1-0 and S1-1(P<0.05).The biomass of S1-0 was consistent with the height diameter of the seedlings,but there was no significant difference in the biomass accumulation of S1-1(P>0.05).The results showed that high N,high P and high K treatment 11(N3P2K2)could promote the synthesis of chlorophyll and soluble protein,and had the maximum net photosynthetic rate.There was a consistent rule between S1-0 and S1-1(P<0.05).(4)The storage of N,P and K of S1-0 was the highest in treatment 10(N:P2O5:K2O=0.4g:0.08g:0.45g)(P<0.05).The storage of N,P and K of S1-1 was the highest in treatment 12(N:P2O5:K2O=0.4g:0.1g:0.6g).Fertilization significantly increased the root morphology index of seedlings,and treatment 3(N:P2O5:K2O=0.2g:0.08g:0.3g)was more conducive to the formation of root morphology of S1-0(P<0.05).The anatomical structure of the 1st-order root showed that the largest diameter of vascular bundle and the V/R of the 1st-order of S1-0 were the in treatment 11(N:P2O5:K2O=0.2g:0.04g:0.15g).For S1-1,treatment 12(N:P2O5:K2O=0.4g:0.1g:0.6g)was more beneficial to the formation of root morphology and vascular bundle of the 1st-order(P<0.05).All the indexes were simulated by equation:For S1-0,the optimum N application rate was 0.33/plant,the optimum P2O5 application rate was 0.06g/plant,and the optimum K2O application rate was 0.2g/plant.For S1-1,the optimum N application rate was 0.68g/plant,the optimum P2O5 application rate was 0.17g/plant,and the optimum K2O application rate was 0.50g/plant.