Effects Of Different Fertilization Methods On Growth Of Quercus Mongolica Container Seedlings

Quercus mongolica is an important dominant tree species in natural forest in Northeast China,which can be used for wind protection,soil consolidation and water conservation.Its leaves,fruits,branches and stems have important economic value.It is of great significance to study the fertilization technology of Quercus mongolica container seedlings for improving seedling quality,raising the survival rate of transplanting and cultivating high-quality Quercus mongolica resources.In this paper,the growth,physiology and nutrient content of Quercus mongolica container seedlings were studied from different fertilization time(spring and autumn),different fertilization amount and different fertilization methods,in order to provide theoretical basis for the future fertilization technology of Quercus mongolica container seedlings.The main results are as follows:1.In autumn fertilization(A)treatment,seedling height,ground diameter,and their increment,biomass decreased with the increase of fertilizer amount,and reached the maximum value in A1(low fertilizer amount)treatment(N: 56 mg/plant,P: 24 mg/plant,K:48 mg/plant),and the seedling quality index was the largest(9.83).In the spring fertilization(S)treatment,the seedling height,ground diameter,and their increment,biomass were the highest in S3(high fertilizer amount)treatment(N: 112 mg/plant,P: 48 mg/plant,K: 96mg/plant),and the seedling quality index was the highest(8.01).Under the condition of low fertilizer,the effect of fertilization in autumn on the growth of container seedlings of Quercus mongolica was significantly higher than that in spring.The biomass and seedling quality index in autumn fertilization treatments were higher than those in CK and spring fertilization treatments.2.In autumn fertilization treatment,the maximum values of chlorophyll a content,chlorophyll b content and total chlorophyll content were in A3(high fertilizer amount)treatment.The content of soluble protein in leaves,soluble sugar,starch and non structural carbohydrate(NSC)in the whole plant increased first and then decreased with the increase of fertilizer application rate,and the maximum values were in A2(medium fertilizer amount)treatment(N: 84 mg/plant,P: 36 mg/plant,K: 72 mg/plant).The contents of chlorophyll a,chlorophyll b,total chlorophyll,soluble protein,starch and NSC contents of the whole seedling were all in S3(high fertilizer amount)treatment in spring.The maximum soluble sugar content of the whole plant was in S2 treatment.Under the same fertilization rate,the content of chlorophyll a,chlorophyll b,total chlorophyll,starch and NSC content of the whole plant were higher in autumn fertilization treatment than in spring fertilization treatment.The soluble sugar and soluble protein content of the whole plant under high fertilizer amount in spring was higher than that in autumn fertilization treatment.3.With the increase of fertilization rate,the concentrations of total nitrogen,total phosphorus and total potassium in the whole plant of seedlings increased at first and then decreased.Under autumn fertilization treatment,the total nitrogen concentration and content of Quercus mongolica reached the maximum in A2 and A1 treatments respectively.The maximum concentrations and contents of total phosphorus and potassium in the whole plant were in A2 treatment.Under spring fertilization treatment,the concentration and content of total nitrogen,total phosphorus and total potassium of S2 treated seedlings were the highest.Compared with the same amount of fertilization,the concentrations and contents of total nitrogen and total phosphorus in autumn fertilization treatment were higher than those in spring fertilization treatment,and the difference was significant under low fertilizer amount.However,the total potassium concentration of the whole plant was higher in the spring fertilization treatment under the low fertilizer amount,and the total potassium content of the whole plant was higher in the autumn fertilization treatment than in the spring fertilization treatment.Under high fertilizer rate,K concentration and content of whole plant in autumn fertilization treatment were higher than that in spring fertilization treatment,and the difference was significant.4.Six different N treatments were set in exponential fertilization experiment,which were CK(0 mg/plant),E1(25 mg/plant),E2(75 mg/plant),E3(125 mg/plant),E4(175mg/plant)and E5(225 mg/plant),respectively.The experimental results show that: With the increase of N application rate,the growth index,physiological index and nutrient content of container seedlings of Quercus mongolica increased first and then decreased.In E3 treatment,seedling height,ground diameter,aboveground and whole plant biomass,soluble sugar content and NSC content in various tissues reached the maximum;The underground biomass and starch content of all tissues were the highest in E2 treatment;All the above indexes were higher than those of no fertilization treatment.The content of chlorophyll increased with time,and the highest in September.The content of soluble protein decreased with time,and the lowest in September.The results showed that the suitable N fertilizer application could significantly promote the absorption and accumulation of nitrogen,phosphorus and potassium.The maximum contents of total nitrogen content in leaf,stem,root and whole plant,total phosphorus and potassium contents in stem,root and whole plant were all at E3treatment;and the maximum contents of total phosphorus and potassium in leaves were in E2 treatment.The contents of all nutrients were significantly higher than those of CK.In conclusion,from the perspective of improving nutrient utilization rate,reducing pollution and waste,and saving costs,fertilization in autumn had a greater promoting effect on Quercus mongolica container seedlings than that in spring fertilization treatment.When nitrogen,phosphorus and potassium were 56 mg,24 mg and 48 mg per plant in autumn,respectively,the growth and nutrient accumulation of Quercus mongolica container seedlings were significantly promoted.The results showed that the nitrogen application rate of index fertilization ranged from 75 mg/plant to 125 mg/plant,which promoted the growth and nutrient accumulation of Quercus mongolica container seedlings significantly,and the nitrogen absorption and utilization efficiency was high.