CLCA Research Funding

The California Landscape Contractors Association (CLCA) established its Environmental Research Funding Program in 1999 to support scientific research on water conservation and natural resource management issues as they relate to landscape design, installation, and maintenance, as well as to quantify and better understand the environmental benefits of landscaping.


The program currently uses two funds to accomplish its purpose:

The former is made up of contributions from individuals and the association as a whole. The latter was funded by a 2006 contribution from CLCA's Sacramento Valley Chapter. The Landscape Educational Advancement Foundation (LEAF), a 501(3) charitable organization, maintains both funds.

Process for Granting Awards

CLCA issues a request for proposals (RFP) for applied research projects on an annual basis. To be placed on the association's mailing list for these announcements or to update contact information, qualified professional researchers at universities, colleges, and other research organizations should send their e-mail address to CLCA Assistant Executive Director Larry Rohlfes at

Research contributions are in the form of gifts or grants-in-aid to researchers or organizations conducting research. The program does not pay for university administration overhead. One hundred percent of all contributions must go to the researcher or researching organization.

Research Advisory Committee

CLCA's Research Advisory Committee awards the grants. The committee consists of the chair of the Resource Management Committee, the director of resource management, a representative from LEAF, a representative from Sacramento Valley Chapter, and at least two affiliate CLCA members from the academic community. If two affiliate members from the academic community cannot be found among the membership, other individuals from the academic community are appointed.

The Research Advisory Committee works independently or with the Resource Management Committee to prioritize researchable issues and to plan the annual RFP process.

How to Contribute to Environmental Research

Contributions to the Environmental Research Funding Program can be sent at any time to CLCA at 1491 River Park Drive #100, Sacramento CA 95815-4501. Tax-deductible checks of any amount are very welcome. They should be made out to LEAF Research.

CLCA recognizes all environmental research benefactors by listing them in the association's newsletter, The Cutting Edge.

More Information

For more information, contact Larry Rohlfes, CAE, at (916) 830-2780 or

Research Reports

Grant recipients are expected to submit a final report of their accomplishments and findings. These reports can be accessed below:

Distribution Uniformity of Multi Stream Multi Trajectory Rotary Nozzles Spaced Below Recommended Distance
Ramesh Kumar, Robert Green, Eudell Vis, Kelly Parkins & Ranil Perera
Study measured low-quarter distribution uniformity (DU) of multi-stream, multi-trajectory rotary nozzles at maximum spacing for head to head coverage and at smaller spacings. The effect of DU of adjusting and not adjusting the radius drew on the nozzle for head to head coverage was also measured. Study found that DU was higher at spacings 10 percent and 25 percent less than the maximum spacings. Adjusting the radius screw to achieve head to head coverage for smaller spacings resulted in a higher DU.
View report (PDF)
Grasscycling As a Tool for Reducing Green Waste and Fertilizer Use on Tall Fescue Lawns in California, Phase 2
David W. Burger
Phase 2 of a study to determine the effects of grasscycling on a tall fescue lawn under California conditions. Effects examined are clipping yield, quantity/color of the turf and minimum amount of fertilizer that can be applied without reducing turf quality.
View report (PDF)
Grasscycling As a Tool for Reducing Green Waste and Fertilizer Use on Tall Fescue Lawns in California, Phase 1
David W. Burger & M. Ali Harivandi
A tall fescue research plot was established on the UC Davis campus to study grasscycling. Study showed that grasscycling tall fescue lawns can reduce nitrogen fertilizer use by 30-55 percent without a perceptible loss in turfgrass quality or color. Long-term effects on soil characteristics (e.g. organic matter, total nitrogen and carbon, nitrate and ammonium) and the evolution of the volatile greenhouse gas nitrous oxide (N2O) will be studied in 2011.
View report (PDF)
Effect of Sand Backfill When Transplanting Palms
Donald R. Hodel, A. James Downer, Maren Mochizuki, and Dennis R. Pittenger
Neither sand nor soil backfill significantly affected growth of transplanted Queen Palms or Windmill Palms. Only King Palms backfilled with sand grew significantly more leaves and had a significantly greener canopy and significantly higher survival rate two years after transplanting. Thus, only King Palms benefitted from sand backfill when transplanted.
View report (PDF)
Effect of Rotary Nozzles and Cycle and Soak Scheduling on Landsape Irrigation Efficiency
Ramesh Kumar, Eudell Vis, Marvin Seaman, Bill Raff & Ashley Scott
Report summarizes findings of research performed on four turf plots that simulated runoff from landscapes onto curbs and hardscapes. Several methods of irrigation were used, and runoff from the sprinkler plots was collected in two components: surface runoff and wind drift runoff. Report concludes, among other things, that proper irrigation scheduling can result in minimal surface runoff with a ten-percent slope. However, wind appears to be a major cause of runoff, even under moderate wind conditions.
View report (PDF)
  1. 2006
    Using a Buffalograss and Fine Fescue Mixture As a Long Term Alternative to the Traditional Lawn for Improved Resource Management
    Terry L. Vassey and Britani Axtell
    Report on the first phase of a study to determine the best combination of buffalograss and fine fescue species for the central California coast and to examine management strategies that would promote year-round turfgrass quality and color in those mixed stands. Seeded and vegetative buffalograss was planted into pre-established fine fescue subplots. The seeded buffalograss did not survive. Because of the slow germination potential of buffalograss and the competitiveness of the fine fescue, the report concludes that it is not possible to establish buffalograss in an existing turfgrass stand by seed. The vegetatively established cultivars did survive and spread, but it took two years to do so adequately.
    View Report (PDF)
  2. 2005
    Effectiveness of Bio-Retention-Infiltration System on Eliminating Dry Weather Runoff from Irrigated Urban Landscape
    Qingfu Xiao
    Reports on field experiments to evaluate the effectiveness of bio-retention infiltration systems in eliminating dry weather runoff from irrigated urban landscapes. Concludes that bio-retention systems are effective in reducing dry weather runoff.
    View Report (PDF)
  3. 2004
    Comparison of Distribution Uniformities of Soil Moisture and Sprinkler Irrigation in Turfgrass
    Ramesh Kumar, Shoumo Mitra, and Eudell Vis
    Compares irrigation scheduling based on lower-quarter distribution uniformity (DULQ) with scheduling based on lower-half distribution uniformity (DULH) to determine which is the more water-efficient method to use and still maintain turf quality. Concludes that scheduling based on DULH results in water savings of about 17 percent over scheduling based on DULQ.
    View Report (PDF)
  4. 2000
    Evaluating Irrigation Needs of Mixed Landscapes for Water Conservation
    Dennis R. Pittenger, William E. Richie, and Robert L. Green
    Evaluates mixed plantings of tall fescue turf, spring cinquefoil groundcover, and Bradford pear when grown in different combinations under two separate irrigation regimes. Study concludes that the most effective means of estimating a mixed landscape's irrigation need is to use the minimum amount of water required by the most water demanding species in the mix as the basis. This amount can be adjusted up or down in small increments of five percent to ten percent of reference evapotranspiration (ETo). There is no evidence that any species, alone or in combination with others, would perform better if the planting were irrigated above 80 percent ETo divided by the distribution uniformity.
    View Report (PDF)