MEMBERS

PRODUCTS

QUALIFICATION

Trialing

Turfgrass Water Conservation Alliance (TWCA) is a 501c3 non-profit dedicated to water conservation and committed to preserving the ecological benefits of turfgrass in the managed environment.  TWCA relies on third party peer review of objective data to qualify the most drought tolerant turf available today. 
Using strong research TWCA advocates for the responsible use of drought tolerant turf in landscapes to preserve the livability and viability of communities around the world.​

TWCA Cooperator demonstrates DIA data collection with a lightbox at NexGen.

Technology
TWCA and its cooperators pioneered the use of Digital Image Analysis (DIA) to collect and evaluate stress related data in turfgrass.  This includes NexGen Turf Research and University of Arkansas developing the lightbox technology widely considered industry standard and developing the Turf Analyzer tool.
These revolutionary technologies, coupled with the use of Rainout Shelters (ROS)s allow effective and accurate evaluation of multi-year multi-site trialing.
Trialing Types
During the single species evaluation process, TWCA utilizes both Drought and Low Maintenance trialing.  Drought trialing gives an accurate accounting of cultivar performance under drought stress.  Low Maintenance trialing, on the other hand, looks at turf performance under a decreased inputs regime.
TWCA evaluates two types of droughts stress: chronic and acute.  Chronic stress is a low water scenario where the turf is brought to uniform green before being watered at a decreased evapotranspiration (ET) rate.  Chronic stress is excellent at simulating water requirements in a decreased water scenario like a daily or weekly watering restriction.  However, it is fairly labor intensive.  TWCA research cooperators have shown through repeated trialing, a high correlation between drought tolerance performance in chronic and acute conditions.  For these reasons, this is a less common approach in the program.  Acute stress, on the other hand, is a zero-water evaluation, where established turf is brought to uniform green and field capacity before the water is entirely shut off.  This is a prolonged drought, no water scenario and provides a smooth uniform performance curve for evaluation.  Drought trialing is governed by the TWCA's Turfgrass Water Conservation protocol.
Low Maintenance trialing presents a unique evaluation challenge.  Unlike TWCA drought trialing with one variability (drought) low-maintenance functions with a broad spectrum of variables.  The trialing regime bans herbicides and pesticides completely and restricts fertility to between 1 and three pounds per one thousand square feet.   Moreover, the low-maintenance regime also imposes acute drought stress.  A key requirement for any cultivars coming out of the low-maintenance regime is qualification through the TWCA Drought process.
Regardless of the trialing regime imposed, all TWCA trials are standardized using the TWCA Cooperators Manual.  This manual lays out expectations for ROS construction, trialing conditions including, establishment, mowing height and fertility.  
​
​Qualification
TWCA Qualification relies on third party peer review of the objective data collected at all the locations.  The TWCA Research Review Committee selects the final qualifications.  Comprised of University Researchers with no vested interest in any cultivar being evaluated, the RRC meets to review and evaluate the data before making the final qualifications.  As qualified cultivars approach expiration, they must either requalify against a new, higher standard of drought tolerance or lose their qualified status.

TRIALING TIMELINE

2010

Individual submissions permitted.

2011

Individual submissions permitted.

Individual submissions permitted.

2012

Individual submissions permitted.

2013

Individual submissions permitted.

2014

14WCLP

2015

15WCPP

2016

16WCFA

2018

18WCPP

 2020

20WCFA

​2024

LOCATIONS

Using a broad geographic trialing range reduces the impact of confounding factors on trial outcomes.

TWCA Code	Cooperator	Location	Most Recent Trial
1	Derr	​Virginia Tech	20WCFAnn
2	Hignight	NexGen Plant Science Center	20WCFAnn
3	Bigelow	Purdue University	20WCFAnn
4	Langlois	​NexGen Plant Science Center, New Jersey	18WCPPnn
5	Richardson	University of Arkansas	20WCFAnn
6	Dodson	Olds	15WCPPnn
7	Lyons	​University of Guelph	20WCFAnn
8	Gregoire	Laval	15WCPPnn
9	Fricker	​Pure Seed Testing	​20WCFAnn
10	Kopp	Utah State	​20WCFAnn
11	Richardson	University of Arkansas  ​LOW MAINTENANCE	16WCFA
12	Frazer	​Pure Seed Testing East	20WCFAnn
13	Hignight	NexGen Plant Science Center ​LOW MAINTENANCE	16WCFA
14	Baird	​​UC Riverside	​18WCPPnn
15	Sorochan	University of Tennessee	16WCFAnn
16	Hignight	NexGen Plant Science Center ​CHRONIC	18WCPPnn
19	Raymer	University of Georgia	​​20WCFAnn
22	Goatley	Virginia Tech, Blacksburg	18WCPPnn
24	Fidanza	Penn State, Berks	​​20WCFAnn