Turfgrass fertiliser recommendations with or without soil tests

My slides for a keynote presentation about fertiliser recommendations at the European Turfgrass Society conference in Manchester, England.

1. Turfgrass fertiliser recommendations with or without soil tests Micah Woods July 2, 2018 Chief Scientist Asian Turfgrass Center www.asianturfgrass.com @asianturfgrass
2. Objective of turfgrass fertiliser applications Ensure the turf is supplied with just what it requires, while at the same time avoiding (or minimizing) overapplication.
4. 1. Short history of the problem.
5. 1. Short history of the problem. 2. Two recent (and general) solutions.
6. 47 years ago …
7. “Fertilizer is the number one management tool. It is worth all the attention you can give it.” Madison, 19711 1Madison, J.H. 1971. Principles of turfgrass culture. New York: Van Nostrand Reinhold Co. p. 270
8. 40 years ago …
9. “A study was conducted to determine differences among soil testing laboratories … in fertilizer recommendations for turfgrass maintenance and establishment.” Turner & Waddington, 19782 2Turner, T.R. and D.V. Waddington. 1978. Survery of soil testing programs for turfgrasses. Comm. Soil Sci. Plant Anal. 9(1):71-87.
10. “Unfortunately, turfgrass recommendations appear to be based on research done with other crops, such as forages, results from turfgrass fertility studies not designed to relate to soil testing, and the best judgement of the agronomist making the recommendations.” Turner & Waddington, 1978
11. Seventeen years ago …
12. “In some cases, turfgrasses have been placed in a ‘high’ P and K requirement category … This decision was based on economics, not agronomics. The cost of fertilization was not considered of primary importance for turf.” Carrow et al., 20013 3Carrow, R.N., Waddington, D.V., and P.E. Rieke. 2001. Turfgrass Soil Fertility and Chemical Problems. Wiley. p. 164.
13. Five years ago … Surely these issues have been resolved?
14. “Calibration of … soil P with turfgrass growth and subsequent P fertilization recommendations is scant, and additional data is needed. Many current recommendations for P fertilizer for turfgrasses are based on forage- or field-crop calibration data.” Frank & Guertal, 20134 4Frank, K.W. and E.A. Guertal. 2013. Potassium and phosphorus research in turfgrass. In: Stier, J.C., B.P. Horgan, and S.A. Bonos, editors, Turfgrass: Biology, Use, and Management, Agron. Monogr. 56. ASA, CSSA, SSSA, Madison, WI. p. 493-519.
15. “Relationships between extracted soil K, K fertilization rates, and turfgrass response needs additional study. Such work is especially missing for the sand-based systems in which many turfgrasses are managed.” Frank & Guertal, 2013
16. Festuca, Iceland
17. Zoysia, Italy
18. Agrostis, Cynodon, and Festuca, Portugal
19. Poa annua, France
20. Reality: Conventional soil test calibration will never be done for even a fraction of the turf species, soil, and climate combinations.
21. Poa pratensis, Japan
22. Paspalum vaginatum, Thailand
23. Axonopus compressus, Indonesia
24. Digitaria didactyla, Sri Lanka
25. Two recent solutions 1. Fertiliser recommendations without soil test data.
26. Two recent solutions 1. Fertiliser recommendations without soil test data. 2. Fertiliser recommendations with soil test data.
27. Fertiliser recommendations without soil test data
28. In this case, it makes sense to apply—at least initially—all that the plant can use.
29. This is the STERF “Precision fertilisation” approach.5 5Ericsson, T., K. Blombäck and A. Kvalbein. 2013. Precision fertilisation—from theory to practice. STERF.
30. “Precision fertilisation is based on the assumption that during vegetative growth …, grass requires nutrients in constant relative proportions.” Ericsson et al., 2013
31. “By matching fertilisation to requirements during the season, it is possible to avoid undesirable fluctuations in grass growth and playing quality.” Ericsson et al. 2013
32. Fertiliser recommendations with soil test data
33. In this case, one wants to ensure the grass is supplied with all that it can use. If the soil can supply some—or all—of that amount, then the fertiliser recommendation accounts for the soil supply.
34. Minimum levels for sustainable nutrition (MLSN) • Joint project6 of ATC (me) & PACE Turf (Wendy Gelernter and Larry Stowell, California) • Started with 16,163 soil samples collected from good-performing turf • Selected a subset of 3,683 with: • pH ≥ 5.5 & ≤ 8.5 • CECsum ≤ 60 mmolc kg-1 6Woods M.S., L.J. Stowell, and W.D. Gelernter. 2016. Minimum soil nutrient guidelines for turfgrass developed from Mehlich 3 soil test results. PeerJ Preprints 4:e2144v1 https://doi.org/10.7287/peerj.preprints.2144v1
41. https://asianturfgrass.shinyapps.io/turfsi/
42. For more, please see www.asianturfgrass.com or @asianturfgrass on Twitter.