Fertilizer & N:K ratios

Nitrogen and potassium, N and K, are the mineral elements used in the largest amounts by turfgrass. In this presentation, delivered on 11 March 2015 at the Sustainable Turfgrass Management in Asia conference, I discussed an experiment we did in Thailand.

N and K were applied in 2:1, 1:1, and 1:2 ratios to manilagrass, bermudagrass, and seashore paspalum. We measured clipping yield, nutrient uptake, and plant water use. Some results are shown here, and additional details are available at http://bit.ly/nk_ratio.

Transcript

1. Fertilizer & N:K ratios Micah Woods Chief Scientist | Asian Turfgrass Center Handout: bit.ly/nk_ratio www.asianturfgrass.com Sustainable Turfgrass Management in Asia 2015 Pattaya, Thailand 11 March 2015
2. Potassium (K), 2 approaches 1. Many turfgrass managers believe more K in relation to N will result in turf with: • more disease resistance • better heat tolerance • drought resistance • better wear tolerance • enhanced root growth 2. I'm confident that if enough K is supplied, ALL those listed benefits occur. Zoysia matrella Thailand
3. We grew 419 bermudagrass, Salam seashore paspalum, & nual noi manilagrass Zoysia matrella Thailand
4. In this experiment we grew the grasses for 6 months, then started the treatments of N:K ratios of 2:1, 1:1, & 1:2. Then for 7 weeks we measured: • clipping yield • water use • leaf water content • nutrient uptake • soil nutrients • leaf nutrients Researchers at 2014 Field Day Thailand
5. N and K were applied weekly, at an N rate of 1 g/m2 Irrigation was applied twice weekly. The grass was maintained as a simulated fairway turf. Cutting by hand shears, with all clippings collected, once a week. measuring water use Thailand
6. These are the grasses during the fourth week of the experiment in December 2013. experimental pots Thailand
16. Each species responded similarly to K. All species had leaf K at normal levels even when a 2:1 ratio was applied. Nual noi 25% more efficient in growth per gram of N applied and 22% more efficient per L of water applied. Slides & PDF handout w/ more details: bit.ly/nk_ratio manilagrass fairway Philippines