Shiny Apps

Web apps for turfgrass data and calculations

I’ve made apps to calculate evapotranspiration, find the past year of DLI at any location, compare your soil test results to the MLSN dataset, see turfgrass industry Twitter rankings, and much more.

You can see the underlying R code for many of these apps on Github.

Global DLI app

Daily light integral (DLI) is the photosynthetically active radiation. This app allows the user to select a location on a world map, then queries the NASA POWER Agroclimatology dataset to obtain the past year of global solar radiation at that location. It then checks the monthly normal solar radiation at that site, and gives the user an option to download a formatted chart with daily, weekly, and monthly DLI for the past 52 weeks.

ET calculator

This app returns the reference and crop evapotranspiration for any day given inputs of latitude, maximum and minimum air temperatures, and crop coefficient. Based on the Hargreaves equation.

Sustainability index

This app returns the sustainability index (SI) based on soil test inputs. This is a direct comparison of input soil test results to the MLSN data.

Users can put in soil test results for K, P, Ca, Mg, and S. The app then shows where the input level of soil nutrients would sit on the cumulative distribution function (CDF) for all the MLSN data.

Irrigation requirement

These apps use weather data from four locations in Thailand, one location in the USA (Corvallis, Oregon), and three locations in the Philippines, to calculate the irrigation water requirement.

The users are able to select the location and then adjust factors that influence the soil moisture content and the irrigation water requirement. These factors include:

  • rootzone depth
  • field capacity
  • minimum soil moisture triggering an irrigation event
  • maximum volumetric water content (VWC) to irrigate to
  • crop coefficient
  • distribution uniformity of the irrigation system

Charts are then generated to show the VWC through the year, given the weather that happened at the selected location, along with the annual irrigation requirement, monthly irrigation requirement, and other interesting summary calculations.

Sunshine & temperature in Japan

Plots the combination of climatological normal sunshine and temperature for 11 cities in Japan. This combination of sun and temperature gives an indication of the growing environment for turfgrass at different locations.

MLSN K calculator

Calculates the fertilizer K requirement given inputs of grass species, soil test K, and annual N rate. A diagonal line on the chart displays how the fertilizer K will change based on the amount of K in the soil.

GP avatar

This app developed with PACE Turf generates a downloadable avatar that shows two lines – blue and red. Blue is the cool-season growth potential through the year, and red is the warm season growth potential. We put this together in a hackathon when I visited PACE Turf headquarters a few years ago.

You can choose built-in temperature data from any zip code in the USA, or can input your own temperature data for any location.

Assorted additional apps

The ET app and the MLSN K calculator are available in Japanese language versions.

このプログラムは、標準蒸発散値(ETo) を、年月日、緯度、その日の最高気温と最低気温を基にしてmm 単位で計算します。算出された ETo に、作物係数を乗算すると、 その作物の蒸発散値(ETc)が求められます。これらの計算はHargreaves の ETo


ここでの計算は、持続可能な最低栄養 (MLSNガイドライン) をベースとしています。


Returns the expected photosynthetic photon flux density (PPFD) for a second within any specified minute, given inputs of latitude, longitude, date, and time. Also returns expected daily light integral (DLI) at that location if it is sunny all day.


I have downloaded turf industry tweets and analyzed them along with account characteristics. This analysis finds some of the most influential industry accounts.