10/20/2023 - By Dr. Jeff Atkinson

Study:                  Evaluating the effect of two Fertilgold Prilled humic acid application rates on creeping bentgrass growth maintained under mild heat and drought stress.

Location:             Growth Chamber Study, Virginia Tech

Investigator:      Dr. Xunzhong Zhang

Summary:           A growth chamber study was conducted by Dr. Xunzhong Zhang at Virginia Tech to investigate the effect of Fertilgold Prilled humic acid on the growth of creeping bentgrass maintained under mild heat and drought stress conditions.  Mature ‘Penn A4’ creeping bentgrass plugs (4-inch diameter) collected from field plots were transplanted into 6-inch pots filled with a USGA specification sand (fine sand with 10% peat) on May 13, 2021. The bentgrass was maintained at 0.39” (10 mm). After 4 weeks of non-stressed growth with optimum temperature (72/64°F, day/night), water, fertilizer, light (400 µmol/m²/s PAR with 12 h photoperiod), and relative humidity (65%), the treatments were initiated. The treatments were applied on June 11 and repeated 30 days later.  Fertilgold Prilled humic acid was applied onto the canopy surface at 25 or 50 lbs/A and watered in immediately. The untreated control received the same amount of water at the same time when the treatments were applied.  All treatments received equal fertility throughout the duration of the experiment. Fertilgold Prillled humic acid applied at 25 lbs/A improved leaf color 28, 42, and 56 days after initial treatment, and improved root biomass, length, surface area, viability, and leaf calcium and magnesium concentration at the end of the study.

Figure 1.  Leaf color following applications of Fertilgold Prilled humic acid to creeping bentgrass grown under mild heat and drought stress. Different letters amongst treatments within the same rating date indicate a statistical difference at the α=0.05 level. DAIT = Days After Initial Treatment. 1 = brown turf; 9 = dark green turf. Virginia Tech, Blacksburg, VA, 2021.

Figure 2.  Root biomass following application of Fertilgold Prilled humic acid to creeping bentgrass grown under mild heat and drought stress. Different letters amongst treatments indicate a statistical difference at the α=0.05 level. Root biomass was measured at the end of the study. Virginia Tech, Blacksburg, VA, 2021.

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