Effects Of Fulvic Acid Potassium On Nitrogen Absorption And Distribution, And Fruit Yield And Quality Of Strawberry

The experiment was conducted in the solar greenhouse at the Horticultural Experiment Station of the College of Horticulture Science and Engineering,Shandong Agricultural University.The test soil was clay loam soil.The strawberry of‘Miao Xiang 7'was used as the test material for two groups of experiments.The technique of stable isotope ¹⁵N-labelled nitrogen was used to one group.The experiments included four kinds of treatments:¹⁵NH4NO3?M0T1?,NH4¹⁵NO3?M0T2?,Fulvic acid potassium and ¹⁵NH4NO3?M1T1?,fulvic acid potassium and NH4¹⁵NO3?M1T2?were respectively applied in the soil.This experiment was used to study the effect of fulvic acid potassium on the absorption,utilization,and distribution of nitrogen in strawberry.The other one set of tests consists of three treatments:tap water treatment?CK?,application of given fertilizer?F1?,application of fulvic acid potassium and fertilizer?F2?.This experiment was used to study the effect of fulvic acid potassium on the yield and quality of strawberry fruit and provide theoretical guidance and basis for the application of fulvic acid potassium in greenhouse strawberry production.The results of the study are as follows:1.The treatment applied fulvic acid potassium can increase nitrogen use efficiency of strawberry.Compared with the treatment without fulvic acid potassium,the results showed that after fulvic acid potassium treatment,ammonium nitrogen and nitrate nitrogen absorption utilization rate respectively increased by 199.70%and 24.40%.And the utilization rate of ammonium nitrogen in strawberry was higher than nitrate nitrogen.The overall performance among the treatments was:M1T1>M1T2>M0T2>M0T1.Without potassium fulvic acid,the strawberry has a high affinity for nitrate nitrogen in a short time.2.Fulvic acid potassium treatment can increase the ability of nitrogen to regulate various organs of strawberry.Under the condition of not applying fulvic acid potassium,the Ndff values of nitrate nitrogen treated by all organs were generally higher than that of ammonium nitrogen.The difference of the ability of the adjustment of ammonium nitrogen and nitrate nitrogen between various organs was not significant,and the Ndff value of root,young leaf and white ripe fruit was higher,and the Ndff value of the green fruit,the flower stalk and the old leaf was lower.After the treatment of potassium fulvate,the Ndff value of all organs marked by ammonium nitrogen treatment was significantly higher than that of the labeled nitrate nitrogen treatment.It showed that after the treatment of potassium fulvate,the ability of the strawberry to adjust to ammonium nitrogen was improved,which was higher than that of nitrate nitrogen.The Ndff values of roots,young leaves and white ripe fruits were higher in all treatments,while the Ndff values of flower stalk,old leaf and green fruit were lower.3.Fulvic acid potassium treatment had less effect on ¹⁵N migration and distribution amo ng organs.The ¹⁵N distribution rate of strawberry organs showed the same trend between the f ulvic acid potassium treatment and the treatment without fulvic acid potassium.The ¹⁵N distri bution rate of the vegetative organs?root,young leaves,and old leaves?was significantly high er than that of the genital organs.?flower shank and fruit?;¹⁵N distribution rate of young leav es in each treatment is the highest,indicating that in the fruit ripening stage,nitrogen is transf erred from the other organs of strawberry to the leaves for theirselves needs.It was learned fro m the above that after treatment of fulvic acid potassium treatment and the treatment without f ulvic acid potassium,there was no significant difference in the distribution rate of ¹⁵N in vari ous organs of strawberry,and it was shown that fulvic acid potassium had a small effect on th e migration and distribution of ¹⁵N in various organs.4.Fulvic acid potassium treatment can increase the SPAD value and the daily net photosynthetic rate of strawberry leaves.After applying fulvic acid potassium,the relative content of chlorophyll,daily net photosynthetic rate and yield of strawberry respectively increased by 1.79%,10.48%and 24.13%,compared with the control.It shows that fulvic acid potassium can promote the synthesis of chlorophylland increase the net photosynthetic rate of strawberry leaves in some extent,thus it can enhance the photosynthesis of the plants.The SPAD value of fertilization treatment was also significantly higher than that of CK,indicating that the appropriate amount of nitrogen fertilizer also facilitates the synthesis of chlorophyll.With the increase of light intensity,the stomata of the leaves were closed,accompanied by the consumption of respiration.The net photosynthetic rate of strawberry leaves at different time points on the same day showed a significant downward trend from 9:00 am to 16:00 pm.5.Fulvic acid potassium combined with inorganic fertilizers can increase the single fruit weight and yield of strawberry.Stochastic sampling of strawberry fruits at different time periods did not differ greatly in the number of fruit in each treatment.The average fruit weight and yield were the highest in treatment F2,followed by treatment F1,and treatment CK was lowest.During the measurement period,the total output of F2 and F1 respectively increased by 24%and 15%compared with CK.The total fruit weight of F2 and F1respectively increased by 24%and 17%compared with CK.Excessive nutrient application could reduce the soluble solid content,reduction Vc content and soluble sugar content of strawberry fruit.The combination of fulvic acid potassium and inorganic fertilizer could effectively reduce the bad effects of excess nutrients on fruit quality.The soluble solids content,reduction Vc content and soluble sugar content of CK in strawberry fruit were highest in the three treatments,followed by F2,and the lowest in treatment F1.Compared with F1 treatment,soluble solids content,reduction Vc content and soluble sugar content in F2 treatment were respectively increased by 3.14%,9.98%and 8.43%,compared with F1.