Minimum Nutrient Requirements for Putting Green Turf

Minimum Nutrient Requirements for Putting Green Turf Micah Woods, Ph.D. Chief Scientist | Asian Turfgrass Center 1 August 2013 Philippine Turfgrass Forum University of the Philippines Los Baños

soil samples collected from research putting green

nutrient research, Cornell University

1. The elemental content of fertilized turfgrass leaves is relatively constant

2. The amount of nitrogen supplied to the grass controls growth and uptake of the other nutrients 3. A temperature-based growth potential can predict how much nitrogen the grass will use 4. The MLSN guidelines ensure that soil nutrient levels remain high enough to produce excellent turf conditions 5. By considering the previous points, mathematically, the minimum nutrient requirement can be determined

1. The elemental content of fertilized turfgrass leaves is relatively constant

research project to study different grass species

Thailand Institute of Scientific and Technological Research

N:P:K ratio in leaves is about 8:1:4

leaf clippings contain nutrients

2. The amount of nitrogen supplied to the grass controls growth and uptake of the other nutrients

“N supply was the primary determinant of turfgrass growth rate, plant nutrient demand, and nutrient uptake. Nitrogen uptake accounted for over 88% of uptake of all other nutrients. Uptake of P and K were strongly related to tissue N content irrespective of soil test levels.” (Kussow et al., 2012)

www.hindawi.com/isrn/agronomy/2012/359284/

Monthly dry matter yield (g/sq. meter)

300

200

100

0 0

5 10 Monthly N rate (g/sq. meter)

15

3. A temperature-based growth potential can predict how much nitrogen the grass will use

4. The MLSN guidelines ensure that soil nutrient levels remain high enough to produce excellent turf conditions

5. By considering the previous points, mathematically, the minimum nutrient requirement can be determined

Using this method, the amount of fertilizer ( F ) to apply is:

F = Harvest

2 (g/m )

+ MLSN

2 (g/m )

- soil test

2 (g/m )

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1F==G.HI8,6:1=F:J=FH8.K,H;9%

100 soil samples from putting greens in 5 countries in SE Asia Median values pH: 6.6 K : 84 ppm P: 44 ppm Ca: 519 ppm Mg: 69 ppm

Clipping yield = (3 x 0.94 x 12) / 0.04 = 846

3 g N/m2 as maximum N rate 0.94 is average GP at Manila 12 months in the year 4% N in leaves

2 g/m

Potassium (K) (846 x 0.02) + (5.2) - (12.5) = 9.6

2 g/m

Phosphorus (P) (846 x 0.005) + (2.7) - (6.6) = 0.6

2 g/m

Calcium (Ca) (846 x 0.0045) + (53.7) - (77.5) = -20 g/m2 none is required as fertilizer

Magnesium (Mg) (846 x 0.002) + (8.1) - (10.3) = -0.5 g/m2 none is required as fertilizer

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