Influences of N, PO and KO fertilizer application amounts on growth of Thunb and soil properties

Abstract

We conducted this study to determine the recommended application rate of fertilizer for Houttuynia cordata Thunb cultivation. The effects of various application levels of N, P₂O₅, and K₂O fertilizers on the growth of this plant were investigated and the associated changes in soil properties were evaluated in the field. Soil pH at harvest time of Houttuynia cordata Thunb did not differ from that before fertilization, whereas EC tended to decrease during cultivation. The soil organic matter (SOM) and available phosphorus increased after treatment, and the amount of applied fertilizer (P₂O₅) and available phosphorus were proportional. The nitrogen absorption amount increased in N 100% treatment, but decreased in N 150% treatment. The phosphorus absorption amount rose with the fertilizer treatment concentration until P₂O₅ 150% treatment. The amount of absorbed potassium decreased in treatments with K₂O 150% and K₂O 200%. The plant length was the longest in N 100%, P₂O₅ 150%, and K₂O 200%. The stem diameter was estimated to be 3.46 - 3.67 ㎜ in N 100 - 200% treatment, 3.55 - 3.67 ㎜ in P₂O₅ 100 - 150%, and 3.79 ㎜ in K₂O 200%. The number of tillers did not differ amongst fertilization treatments. The fresh weight was summed to be 3.67 ton/10 a in N 100% treatment, 3.79 Mg/10 a in P₂O₅ 150%, and 3.83 Mg/10 a in K₂O 150%. Thus, the relationship between the fertilizer amount and yields of the plant showed that the most economical quantity of fertilizers should be 10.2 N ㎏/10 a, 5.5 P₂O₅ ㎏/10 a, and 8.2 K₂O ㎏/10 a for Houttuynia Cordata Thunb.