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A Modern Method for Estimating Turfgrass Nutrient RequirementsMicah Woods, Ph.D.Chief Scientist | Asian Turfgrass Center7 October 2014Idaho GCSA Fall MeetingPinecrest Golf Course, Idaho Fallsseminar.asianturfgrass.com/2014_igcsa.html
We need to know 3 quantities
L-93 creeping bentgrassIthaca, New York
1. How much of an element is
present in the soil?
2. How much of an element is
needed in the soil?
3. How much of an element does the grass use?
As the grass grows, and as it is mowed, nutrients are removed Kyushu, Japan
Element C3 grass
N 4%
K 2%
P 0.5%
Ca 0.5%
Mg 0.2%
S 0.2%
Macro and secondary nutrient content in grass leaves
http://www.paceturf.org/journal/new_and_improved_climate_appraisal_form
bent & Poa annua may use 0.6 lbs N/1000 ft2/month in good weather Oregon, USA
2.8
1.4
0.35 0.350.14 0.14
0
1
2
3
4
N K P Ca Mg SElement
Pred
icte
d U
se p
er 1
000 (ft
2 )
We need to know 3 quantities
L-93 creeping bentgrassIthaca, New York
1. How much of an element is
present in the soil?
2. How much of an element is
needed in the soil?
3. How much of an element does the grass use?
ReferenceMinimum Levels for Sustainable Nutrition
Soil Guidelines
The Minimum Level for Sustainable Nutrition (MLSN) Guideline is a new, more sustainable ap-proach to managing soil nutrient levels that can help you to decrease fertilizer inputs and costs, while still maintaining desired turf quality and playability levels. The MLSN guidelines were devel-oped in a joint project between PACE Turf and the Asian Turfgrass Center. All soil analyses were conducted at Brookside Laboratories, New Bremen, OH.
Nitrogen requirements are best determined based on turf growth potential, which incorporates
Course Management, p. 108-113, March, 2005).
September, 2014
MLSN Soil
Guideline
pH >5.5
Potassium (K ppm) 37
Phosphorus (P ppm) 21
Calcium (Ca ppm) 331
Magnesium (Mg ppm) 47
Sulfur as sulfate (S ppm) 7
http://www.paceturf.org/journal/global_soil_survey
The amount of fertilizer to apply is:
The amount we need
minus
The amount we have
The amount we need is:
the amount the grass will use (harvest)
plus
the amount we need to retain in the soil (MLSN)
The amount we have is:
the amount in the soil (soil test result)
Expressed as an equation, the amount of fertilizer (F) to apply is:
MLSN (lbs/1000 ft2) + Harvest (lbs/1000 ft2)
- soil test (lbs/1000 ft2) = F
Reference
©2014 PACE Turf, LLC 1267 Diamond Street, San Diego CA 92109 www.paceturf.org
Minimum Levels for Sustainable Nutrition
Soil Guidelines
The Minimum Level for Sustainable Nutrition (MLSN) Guideline is a new, more sustainable ap-proach to managing soil nutrient levels that can help you to decrease fertilizer inputs and costs, while still maintaining desired turf quality and playability levels. The MLSN guidelines were devel-oped in a joint project between PACE Turf and the Asian Turfgrass Center. All soil analyses were conducted at Brookside Laboratories, New Bremen, OH.
How the guidelines were developed
not poor performing turfgrasspH 5.5 - 8.5 to avoid aluminum toxicitytotal exchange capacity <6 cmol/kg
-tion (in ppm) of each nutrient that 10% of the soil samples fell below, but were still performing well. This 10th percentile value is the MLSN soil guideline shown above.
For more information, see the Facebook MLSN page at: www.facebook.com/mlsnturf
version 14091801
Nitrogen requirements are best determined based on turf growth potential, which incorporates
Course Management, p. 108-113, March, 2005).
September, 2014
MLSN Soil
Guideline
pH >5.5
Potassium (K ppm) 37
Phosphorus (P ppm) 21
Calcium (Ca ppm) 331
Magnesium (Mg ppm) 47
Sulfur as sulfate (S ppm) 7
How to convert between ppm and lbs/1000 ft2?
Adding an element as fertilizer:
1 lb/1000 ft2 will increase the top 4 inches by 34 ppm
0.1 lb/1000 ft2 will increase the top 4 inches by 3.4 ppm
As the plant harvests elements:
1 lb/1000 ft2 will decrease the top 4 inches by 34 ppm
0.1 lb/1000 ft2 will decrease the top 4 inches by 3.4 ppm
MLSN (lbs/1000 ft2) + Harvest (lbs/1000 ft2)
- soil test (lbs/1000 ft2) = F
let’s say we harvest 1.4 lbs K and
soil test K is 50 ppm
MLSN (37 ppm) + 1.4 lbs/1000 ft2
- soil test (50 ppm) = F
1.1 lbs/1000 ft2 + 1.4 lbs/1000 ft2
- 1.5 lbs/1000 ft2 = F
1.1 lbs/1000 ft2 + 1.4 lbs/1000 ft2
- 1.5 lbs/1000 ft2 = 1 lbs/1000 ft2
1.5
−1.4 0
0.0930.0
0.5
1.0
1.5
Soil Test AnnualPlant Uptake
FertilizerApplied
Remainingin Soil
K, lb
s pe
r 100
0 (ft
2 )
1.5−1.4 1
1.10.0
0.5
1.0
1.5
Soil Test AnnualPlant Uptake
FertilizerApplied
Remainingin Soil
K, lb
s pe
r 100
0 (ft
2 )
15
−0.35 0
150
5
10
15
Soil Test AnnualPlant Uptake
FertilizerApplied
Remainingin Soil
Ca,
lbs
per 1
000 (ft
2 )
2.8
1.4
0.35 0.350.14 0.14
0
1
2
3
4
N K P Ca Mg SElement
Pred
icte
d U
se p
er 1
000 (ft
2 )
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