Effects Of Exponential Fertilization On Seedling Growth Of Metasequoia Glyptostroboides,Taxodium Ascendens And Taxodium Distichum

The quality of seedling is the primary factor influencing the effect of afforestation.Exponential fertilization can effectively increase the nutrient load in seedling and enhance the seedling competition ability.In this paper,the effects of nitrogen index fertilization on seedling growth and nitrogen accumulation of Metasequoia glyptostroboides,Taxodium ascendens and Taxodium distichum were investigated to provide a basis for seedling cultivation.With the seedlings of Taxodium ascendens,sequoias and deciduous cypress as the materials,the greenhouse potting method was adopted to set the routine fertilization(CF,net nitrogen dosage g·plant^-1)and exponential fertilization(EF1,EF2,EF3,EF4,net nitrogen dosage 1.0,3.0,5.0,8.0 g·plant^-1).The ground diameter,seedling height,biomass,nitrogen,phosphorus and potassium were measured regularly.,main research results are as follows:1)The growth of seedling height and ground diameter was accelerated by exponential fertilization.The seedling height of Metasequoia glyptostroboides and Taxodium ascendens treated with EF1 was significantly higher than CF?P<0.05?.The ground diameter of Metasequoia glyptostroides treated with EF2 was significantly higher than that of CF?P<0.05?,the Taxodium ascendens ground diameter treated with EF2 was significantly higher than CF?P<0.05?,and the seedling height and EF2 treated with EF3 were significantly higher than CF?P<0.05?.2)Exponential fertilization increased the biomass of Metasequoia glyptostroboides,Taxodium ascendens,Taxodium distichum.At the end of the experiment,the biomass accumulation in the subterranean department of metasequoia significantly increased?P<0.05?,and the total biomass treated by EF3 was the highest(increased by 115.2 g·plant^-1).Compared with CF,the biomass of Taxodium ascendens treated by EF increased by 27.9%⁶4.4%.The aboveground,subsurface and total biomass increased by 42.9%,44.3%and 43.5%?P<0.05?.?3?The accumulation of nitrogen,phosphorus and potassium in Metasequoia glyptostroboides,Taxodium ascendens,Taxodium distichum was increased by exponential fertilization.Compared with CF,the nitrogen accumulation amount in the subsurface of Taxodium ascendens treated by EF increased by 49.2%⁸4.4%?P<0.05?,in which the nitrogen accumulation amount of Taxodium ascendens treated by EF3 was the maximum,reaching 2,938.9 m g·plant^-1.The nitrogen accumulation of Taxodium ascendens treated by EF increased by 35.3%⁹4.4%?P<0.05?.The accumulation of phosphorus and potassium in Taxodium ascendens underground showed that the treatment of EF1,EEF2and EF3 was significantly higher than that of CF?P<0.05?.The nitrogen accumulation amount in the underground part of the deciduous cypress was significantly increased by 37.5%⁸6.6%,the nitrogen and potassium accumulation amount in the aboveground part of EF1,EF2 and EF3 was significantly higher than that in CF?P<0.05?,and both of them were significantly higher than that in CF?P<0.05?.?4?The total biomass and nitrogen,phosphorus and potassium accumulation of Metasequoia glyptostroboides fortunei treated with EF3 reached the maximum,and the optimal fertilizer application amount for the cultivation of annual seedlings of Metasequoia glyptostroboides fortunei was 5.0g·plant^-1.EF2 treatment resulted in the maximum plant height,ground diameter and potassium and phosphorus accumulation of Taxodium ascendens,while EF3 treatment resulted in the maximum biomass and nitrogen accumulation.Therefore,the optimal application amount of annual seedlings of Taxodium ascendens was 3.0⁵.0g·plant^-1.The ground diameter,total biomass and nitrogen,phosphorus and potassium accumulation of Taxodium distichum under EF2 treatment reached the maximum,so the optimal fertilizer application amount of Taxodium distichum seedlings was 3.0g·plant^-1.