Effects of Spring Applications of K Fertilizer On Early Growth of Tall Fescue (Festuca arundinacea Schreb.).

Tall fescue (Festuca arundinacea Schreb.) is the major turfgrass species in northern China where plants typically enter dormancy in October and resume growth in March. This research was to investigate if sequential applications of K fertilizer promote early growth of tall fescue during spring. Field experiment designed as a completely randomized block with 4 replications was conducted in Shannxi, China. Sequential applications of K fertilizer at the rate of 0, 4, 8, 12, and 16g K2O /m2 at 10 days intervals was applied following the initiation of spring green-up. Total 6 applications were applied in March and April. Plant height, leaf length, chlorophyll content, alive shoot and green leaf counts per 100 cm2, and shoot biomass were measured 7 days after each K application. Results showed that K application significantly improved tall fescue spring growth evidenced by increased plant height, leaf length, alive stems and green leaf counts, and shoot biomass following spring green-up. Bigger effects were observed at 8 weeks after the initial K application (WAIA). For example, K applied at 16g K2O /m2 increased ~180% more shoots compared to untreated control. However, spring application of K fertilizer did not affect the color of the green leaves that no significant differences were found on chlorophyll content. Collectively, our results suggested that application of K fertilizer following spring green-up increases tall fescue growth with 8g K2O /m2 the best rate to avoid excessively stimulate fast growth during the spring.