12/27/2022 - By Dr. Raymond Snyder

A field study was conducted on both bentgrass and bermudagrass based on the beneficial effect of potassium silicate observed in Dr. Xunzhong Zhang's growth chamber study. The objective was to determine if regular applications of potassium silicate in a field setting have the same plant health benefits observed in the growth chamber study.

Silicon Benefits on Turfgrass: Field Study - Roots

The following measurements took place in both field studies at day 0, 14, 28, 42, 56, 70, and 84 after initial treatments (additional measurements took place during two dry-down cycles as described below):

·         Turf quality: Turf quality was rated biweekly on a visual scale of 1-9 with 9 indicating the best quality and 6 being minimum acceptable quality.

·         Leaf color: Leaf color was rated biweekly on a visual scale of 1 – 9 with 9 indicating the dark green color, and 1 indicating brown color.

·         Photochemical efficiency (PE): The PE was measured biweekly with a chlorophyll fluorometer based on the Fv/Fm, which is the ratio of variable chlorophyll fluorescence (Fv) to maximum chlorophyll fluorescence (Fm). Leaves were dark-adapted for 15 minutes before each measurement; three readings were collected from each plot and the average was used for statistical analysis.

·         Leaf chlorophyll content: Leaf samples were collected biweekly, and chlorophyll content was determined using spectrophotometer method (Zhang et al., 2005).

·         Leaf carotenoids content: Leaf samples were collected biweekly and carotenoids content was determined using spectrophotometer method (Zhang et al., 2005).

·         Leaf antioxidant superoxide dismutase (SOD) activity: Leaf samples were collected biweekly, and the SOD activity was analyzed according to the method as described by Wu et al. (2017).

·         Leaf Si content: Leaf Si content was extracted and analyzed according to the method by Elliott and Snyder (1991) with minor modifications.

·         Root characteristics and biomas: At the end of the trial, 4 root samples (1.9 cm diameter and 15.24 cm deep) were collected from each plot and washed and root dry weight was determined after the samples were dried at 70 ᵒC for 72 h. The root length, root diameter, root surface area, and root volume were analyzed using WinRhizo technology. Briefly, after fine cleaning of each root sample, the sample from each plot was divided into multiple subsamples. Each subsample was scanned using WinRhizo and all root morphological parameters were generated and analyzed.

·         Root viability. Root viability was analyzed using TTC method (Zhang et al., 2021). Root viability is a good indicator of root function.

Silicon Benefits on Turfgrass: Bentgrass – Root Length and Mass

This study was carried out on the creeping bentgrass putting greens at Virginia Tech Turfgrass Research Center in Blacksburg, VA. The trial included three treatments with four replications. The plot size is 5 x 6 ft. Regular mowing and irrigation were performed. A randomized block design was used.

Treatments:

1. Fertilized Control (0.15 lb N/1000 ft² biweekly)

2. K silicate 3 fl oz per 1000 sq ft biweekly + fertilized control

3. K silicate 6 fl oz per 1000 sq ft biweekly + fertilized control

The trial lasted for 12 weeks from June 8 through August 31 and a total of 6 treatment applications.

Results

Potassium silicate applied at 6 fl oz per 1000 sq ft biweekly increased turf quality on June 30, July 6, July 12, August 17, and August 31.

Potassium silicate applied at 6 fl oz per 1000 sq ft biweekly increased leaf color on June 30, July 6, July 12, July 20, August 17, and August 31.

Potassium silicate applied at 6 fl oz per 1000 sq ft biweekly increased chlorophyll content on July 20, August 3, August 17, and August 31.

Potassium silicate applied at 6 fl oz per 1000 sq ft biweekly increased leaf silicon content on August 3, August 17, and August 31.

Potassium silicate applied at 6 fl oz per 1000 sq ft biweekly increased root biomass, length, surface area, volume, and viability.

Silicon Benefits on Turfgrass: Bermudagrass – Root Length and Mass

This study was carried out on the ultradwarf bermudagrass putting greens at the Independence Golf Course Research Putting Greens in Richmond, VA. The trial included three treatments with four replications. The plot size is 6 x 6 ft. Regular mowing and irrigation were performed. A randomized block design was used.

Treatments:

1. Fertilized Control (0.15 lb N/1000 ft² biweekly)

2. K silicate 3 fl oz per 1000 sq ft biweekly + fertilized control

3. K silicate 6 fl oz per 1000 sq ft biweekly + fertilized control

The trial lasted for 12 weeks from June 3 through August 26 and a total of 6 treatment applications.

Results

Potassium silicate applied at 6 oz/1000 sq ft biweekly improved turf quality on two observation dates, July 15 and August 26.

Potassium silicate applied at 6 oz/1000 sq ft biweekly improved leaf color on three observation dates, July 15, August 17, and August 26.

Potassium silicate applied at 6 oz/1000 sq ft biweekly increased chlorophyll content on two observation dates, July 29 and August 26.

Potassium silicate applied at 6 oz/1000 sq ft biweekly increased leaf silicon content on four dates, July 1, July 29, August 12, and August 26.

Potassium silicate applied at 6 oz/1000 sq ft biweekly increased root biomass, length, volume, and viability.

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If you have any questions about any of the research presented here or how you can develop an agronomic plan for your turf, reach out to your local Harrell's Rep.