9/7/2021 - By Dr. Jeff Atkinson

Conclusion:

Applications of POLYON® Controlled-Release Fertilizer in fall 2019 and spring 2020 in combination with Dimension® applied in spring 2020 provided 100% crabgrass control throughout 2020 (Figure 1; Figure 2).  POLYON® applied only in fall 2019 in combination with Dimension® applied in spring 2020 provided 94% crabgrass control. Dimension® applied in spring 2020 without fertility provided 91% control - significantly less crabgrass control than all POLYON® + Dimension® treatments. Fall + spring POLYON® without Dimension® provided up to 40% crabgrass control in early August, but control was poor (<5%) from late August onward (data not shown). 

Plots receiving fall 2019 POLYON® application resulted in higher turfgrass quality in spring 2020.  Application of POLYON® in fall 2019 and spring 2020 in combination with Dimension® applied in spring 2020 provided the highest turfgrass quality throughout the experiment. Fall 2019 POLYON® + spring 2020 Dimension® resulted in poorer turfgrass quality than fall POLYON® + spring POLYON® + spring Dimension® from June 20 until the conclusion of the experiment but greater quality than the Dimension® + no fertilizer program on most rating dates. Turfgrass quality in the spring 2020 Dimension® + no fertilizer treatment was low (= 6) from 6 June until the conclusion of the experiment despite >90% crabgrass control.

This trial further confirms the benefit of incorporating POLYON® Controlled-Release Fertilizer into a balanced approach program for smooth crabgrass control and enhanced turfgrass quality in fine turf areas.

Figure 1. Treatment effects from different fertility and herbicide programs for crabgrass control. F = Fall 2019; S = Spring 2020. Pictures taken August 31st, 2020. North Brunswick, NJ.

Figure 2. September 7th, 2020 – Smooth crabgrass (Digitaria ischaemum) control provided by fertilizer and herbicide treatments applied at the Rutgers Horticulture Farm No. 2 in North Brunswick, NJ. Fall 2019 - September 2020. Bars with different letters are statistically different at the a=0.05 level. 

Figure 3. Turfgrass quality following fertilizer and herbicide treatments applied to Kentucky Bluegrass (Poa pratensis) at the Rutgers Horticulture Farm No. 2 in North Brunswick, NJ. Turf quality was rated on a 1 to 9 scale with 1 representing poor turf quality and 9 representing excellent turf quality. Data points within the same rating date with different letters are statistically different at the a=0.05 level.

About Dr. Jeff Atkinson
Dr. Jeff Atkinson serves as Harrell’s Director of Agronomy for the Northern United States. In this role, Dr. Atkinson is responsible for the testing and development of proprietary products to expand Harrell’s portfolio and to provide technical support to our sales representatives and customers. Dr. Atkinson has experience in research and development across several disciplines of golf course agronomics. His work can be found in both industry and peer-reviewed journals. Dr. Atkinson has worked in the turf industry for 15 years and holds a bachelors, masters, and doctorate degree from Clemson University. His graduate research focused on the physiological effects of shade on putting green turf, herbicide efficacy and turfgrass tolerance, and biology of invasive species.