Micah Woods
December 13, 2018
1.5k

# Turfgrass growth potential and measuring clipping volume

These slides were used to introduce and explain the magic of a temperature-based turfgrass growth potential. One can get a starting point estimate of turfgrass nutrient use by what seems like magic, starting with high and low daily air temperatures and ending up with, for example, a daily or weekly or monthly expected magnesium use by the grass. I then went on to explain that one can measure what actually does happen by measuring the clipping volume of the grass as it is mown.

## Micah Woods

December 13, 2018

## Transcript

1. ### Turfgrass growth potential and measuring clipping volume Micah Woods 13

December 2018 Chief Scientist Asian Turfgrass Center www.asianturfgrass.com

3. ### Grasses can grow well when temperatures are close to an

optimum for growth, and grasses grow more slowly as the temperature moves away from the optimum.
4. ### Temperature-based growth potential PACE Turf developed the Temperature-based GP to

express the actual temperature in terms of its proximity to optimum temperatures for shoot growth. GP = e−0.5( t−to var )2 where, GP = growth potential, on a scale of 0 to 1 e = 2.71828, a mathematical constant t = average temperature for a location, in celsius to = optimum temperature, 20 for C3 grass, 31 for C4 grass var = adjusts the change in GP as temperature moves away from to ; I suggest 5.5 for C3 and 7 for C4
5. ### Implications and use of GP • mowing frequency • fungicide

duration • heat-related stress • topdressing requirement • nutrient use

9. ### Use of clipping volume 1. Growth rate 2. Green speed

3. Nutrient use and supply
10. ### Use of clipping volume 1. Growth rate 2. Green speed

3. Nutrient use and supply 4. Consistency
11. ### Use of clipping volume 1. Growth rate 2. Green speed

3. Nutrient use and supply 4. Consistency 5. Topdressing

26. ### For bentgrass, with every 10 mL/m2, expect a dry matter

harvest of 0.6 g/m2.
27. ### Then resupply as desired For example, 200 mL/m2 of bentgrass

≈ 0.5 g N/m2. And 0.25 g K/m2. And so on.

33. ### “41% of members and players complain that sanded greens play

poorly, according to turf managers who participated in recent GCI research.” GCI Magazine—April 2018

35. ### Table 1: Annual clipping volume at that location from 2013

to 2016 Year Volume Estimated dry weight N applied L/m2 g/m2 g/m2 2013 4.4 266 NA 2014 3.4 201 13 2015 2.9 172 10 2016 2.4 142 8.5