Engineering better irrigation in turf: quantifying impacts of application uniformity on turf quality in golf


This project aimed to quantify links between irrigation heterogeneity (non-uniformity) and turf management and provide industry guidelines for greenkeepers and course managers on irrigation management and reducing environmental impacts. The 3-year PhD study combined fieldwork in the UK, Denmark and Norway to (i) calibrate and validate a ballistics model for simulating sprinkler irrigation uniformity and performance, and (ii) parameterise a biophysical model (STICS) to simulate fine turf growth and development and impacts on dry matter production (clippings) and nutrient leaching risks. The work was informed by liaising with greenkeepers and key informants in the Scandinavian golf industry.

Golf sprinkler irrigation modelling
Successful validation and calibration of a ballistics model to simulate overlapped irrigation distribution patterns and non-uniformity on golf greens under varying conditions (changing wind speed and wind direction), operating pressures and sprinkler spacings.  

Modelling turf growth and development
STICS model successfully calibrated and validated and then used to model a range of irrigation system and irrigation scheduling scenario. Modelling showed that system design plays a crucial role in achieving high irrigation uniformity, particularly sprinkler position and spacing. Greater spacing between sprinklers decreased irrigation rates and significantly decreased uniformity, particularly at wind speeds >2 m s-1. The pressure and nozzle sizes tested did not significantly affect uniformity. Non-uniform irrigation had a considerable impact on the spatial variability in turf growth, soil moisture content, drainage and leaching. In the northern European climate, irrigation strategy had a more significant impact on turfgrass response than irrigation uniformity. A moderate deficit strategy (replacing 60% potential evapotranspiration) gave the highest growth rates (233 ± 10.6 g m-2), reduced irrigation water use and minimised nitrate leaching in drainage. An inadequate irrigation schedule combined with poor irrigation uniformity (CU <60%) led to a threefold increase in water use and 114% and 50% increase in drainage and nitrate leaching, respectively. Inadequate irrigation practices had little impact on turfgrass growth, which could be misleading as excess irrigation might not affect plant growth and visual quality but would mask poor irrigation uniformities, leading to water overuse and an increased risk of groundwater contamination.

Jerry Knox

Jerry Knox, Cranfield Water Science Institute, Department of Environmental Science and Technology, Cranfield University, Bedford MK43 0AL, UK. Phone: +44 (0) 1234 758365 Email:

Category: Water, nutrients, construction
Status: Ongoing
Project period: OCTOBER 2014 - JUNE 2018

Fundings (kSEK)















Other sources
(Cranfield University)















Project objectives

  • To assess the environmental impacts of irrigation heterogeneity on turf quality, water use and nutrient uptake.
  • To evaluate irrigation management practices using two case study golf courses in Norway (Oslo GC) and Denmark (Furesø GC).
  • To review current irrigation practices, scheduling methods and equipment operation and management through fieldwork and industry survey.
  • To calibrate a ballistic model to simulate irrigation application (uniformity, adequacy, efficiency) under contrasting climate and turf management scenarios.
  • To interview greenkeepers, irrigation engineers and representatives from the Scandinavian golf industry in order to assess turf irrigation management practices and how these relate to system design.
  • To develop best management practice guidelines for the Scandinavian golf industry.

Project participants

Jerry Knox


Cranfield Water Science Institute, Department of Environmental Science and Technology, Cranfield University, Bedford MK43 0AL, UK

+44 (0) 1234 758365

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