The persistence of color response to fertilizer treatments is an important criterion of turfgrass performance. Centipedegrass (Eremochloa ophiuroides (Munro) Hack.) is widely used throughout sub-tropical region, and was selectedas the subject of this study. Four N treatments were applied, with NH4NO3monthly atan application rate of 0, 2.5(1.4), 5.0(2.8), and 10.0(5.6) g-N/m2 (oz). A slow-release fertilizer applied as Osmocote at an application rate of 7.5g-N/m2 was added to each treatment. The trial was conducted in the greenhouse for 12 weeks. Chlorophyll content, N content, leaf area, plant biomass measurement, and growth characteristics were used to determine turfgrass growth qualities. From the results we found that highest average plant height, leaf length, leaf width, shoot dry weight (DW), and root DW were obtained with all fertilizer products application than without N fertilizer input. Regardless ofN fertilizer concentrations, the first leaf, and third leaf CMR increased with N treatments compared to the control in this study. Centipedegrass CMR closely corresponded to N application concentration. The experimental results revealed that average sufficiency index (142) showed an adequate amount of tissue N supplied at this stage of centipedegrass growth. Linear regression of leaf chlorophyll content and CMR values was found in this study (r2=0.9436, P<0.01). This research suggested that the chlorophyll meter could be useful to directly understand the tissue N in centipedegrass. The linear regression of dry weight-based or area-based N concentration on leaf CMR values was highly significant (P<0.01). The results also illustrated that CMR values correlated with Ndw (r2=0.9034) (N content/dry weight) better than with Na (r2=0.7611) (N content/leaf area), indicating that CMR estimated Ndw better than Na. Thus, this investigation suggested that Ndw is the major contributor to variation in SPDA-502 chlorophyll meter readings. Chlorophyll meter measurement can offer an alternative to the tissue test, and can aid in determining fertilizer N recommendations for centipedegrass was demonstrated in this study.
Key words: Centipedegrass, chlorophyll meter readings, N content, dry weight.
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