Biostimulants and Ballfields Erik Ervin Professor Turfgrass Culture

Biostimulants and Ballfields Erik Ervin, Professor Turfgrass Culture & Physiology Virginia Tech

Two main biostimulant ingredients • Humics = humic and fulvic acids – A natural source of rooting hormone = AUXIN • Seaweed extracts – A natural source of chlorophyll-stabilizing hormone = CYTOKININS

Humic Substances Derive from the decomposition (or humification) of carbon containing compounds (plant or animal) Source: Brady & Weil, Soil Science

Humic Substances defined ü Humic substances comprise 60 -80% of soil OM and are the components of OM most resistant to microbial decomposition ü Classified into: Ø Fulvic acid: smallest & soluble in acid & alkali Ø Humic acid: medium & soluble in alkali Ø Humin: largest, most persistent, dark, insoluble ü Sources Ø Leonardite (mined soft coal, lignite): 30 -80% HA, 150 CEC Ø Peats: 5 -25% HA, Ø Biosolids/Compost: 3 -15% HA

Humic Acid has been shown to increase photosynthesis and root growth ü In a greenhouse experiment, Crenshaw bent was grown in solution culture supplied with non-limiting nutrients (no stress) and 3 concentrations of HA. ü Photosynthesis and root growth was increased significantly from 1 to 4 weeks after treatment by HA at 400 ppm (0. 0004%) ü VT foliar spray rate ~5000 ppm Liu, Cooper, Bowman. 1998. Hort. Science 33: 1023 -1025

Auxin or IAA: a component of humics • • Produced in new leaves Cell division & Stem elongation Induction of rooting In combination with cytokinins they regulate ratio of tillering to root initiation and growth • Bending of shoots toward light, roots towards gravity • IAA overproducing mutants of Arabidopsis are known as “rooty” and “superroot” Rogg & Bartel. 2001. Developmental Cell. 1(5): 595 Turf

KBG sod establishment on sand ü Two humic substances sources compared against fertilizer only; fertilizer inputs equalized ü Peat based versus leonardite, both applied at 3 oz/M every 2 wks for 6 applications Table 4. Humic acid (HA) effects on monthly post-transplant root strength measurements of Kentucky bluegrass Treatment Root Strength 22 May 2002 21 June 2002 22 July 2002 -2 --------------- kg m ---------------Control 367. 4 a 483. 7 a† 470. 1 a‡ Leonardite HA 401. 1 a 532. 6 a 587. 6 b Peat HA 430. 7 a 600. 5 b 593. 0 b Treatment Control Leonardite HA Peat HA Root mass ----mg cm-3 -------0. 60 a‡ 34 and 73% transplant rooting increase 0. 85 b 1. 06 b

KBG sod establishment on sand Ervin et al. , 2005. Acta Hort

Kelp or Seaweed Extracts (SWE) • Why do they tend to be in every biostimulant? • Where do they come from and what’s in them? – N. Atlantic rockweed=brown algae=Ascophyllum nodosum – Contain carbos, aminos, minor nutrients, CYTOKININS, Auxin, GA betaines (dehydration avoiders) Turf

Stay-green mutant of corn due to maintenance of high leaf cytokinin levels Loss of ACC oxidase expression stops ethylene’s effects on cytokinin degradation and senescence is delayed under drought (above) and light deprivation (below) From: D. R. Gallie, Biochemistry, UC-Riverside Turf

Root-injection of synthetic cytokinin improved bentgrass heat stress tolerance Means are from 56 d of heat treatments and 56 d after Zeatin Riboside (ZR) injection into the root zone; All mean comparisons are diff. at P=0. 05 Turf Adapted from Liu et al. , 2002. Cytokinin effects on creeping bentgrass responses to heat stress. Crop Sci. 42: 457 -472.

Root-injection of synthetic cytokinin improved bentgrass heat stress tolerance Means are from 56 d of heat treatments and 56 d after Zeatin Riboside (ZR) injection into the root zone; All means are sig diff. at P=0. 05 Adapted from Liu et al. , 2002. Cytokinin effects on creeping bentgrass responses to heat stress. Crop Sci. 42: 457 -472. Turf

Seaweed extract (SWE) contains cytokinins (75 -100 ppm) and improved bentgrass drought resistance Data taken at end of 28 -d dry-down where Θv = 5%; All mean comparisons are diff. at P=0. 05 Adapted from Zhang and Ervin, 2004. Crop Science, 44: 1737 -1745 Turf

SWE + HA improve creeping bentgrass drought resistance 5. 4 b 5. 5 b 6. 3 a 4. 4 c Av. Quality for Penncross, L-93, G-2 1. 12 b 1. 45 a 1. 60 a 0. 95 c Av. root mass for Penncross, L-93, G-2 Source: Zhang and Ervin, 2004. Crop Science, 44: 1737 -45

HA+SWE had no effect under optimum temperature and moisture conditions Ervin &Zhang Turf kept at FC = 34% H 20

Check Aca SWE OO SWE CK-check ashed-SWE End of 2006 trial, 49 days of heat stress Turf

Biostimulant Testing on Virginia Tech’s Soccer Game Field Erik Ervin Josh Mc. Pherson and X. Zhang Virginia Polytechnic Institute and State University

Field Details • Rootzone is a modified soil, Cambridge sand-slit system installed in summer 03. • Big-roll Kentucky bluegrass sod installed July 28, 2003 over a 1” sand cap and played on 3 weeks later • Getting adequate rooting through 1” layer was a problem

Soccer Field Experiment Objective: determine the effects of various season-long biostimulant programs on field performance under regular season play (women’s soccer and lacrosse; men’s soccer) Measured: – Color and Percent Cover – Divot (or Shear) strength – Root strength – Antioxidant activity and Photochemical Efficiency

Products Tested Soluble potash. . . . 6% Iron. . . 1. 4% Humic and Fulvic acid extract. . . 35. 4% Kelp Extract. . . . 4. 8% Siloxane surfactant. . . 1. 4% Manure extract. . . . 0% 1% 0. 36% 9% 1. 2% 0. 36% 74. 3%

Products Tested Iron. Roots 2 Guaranteed nutrient analysis Available Phosphate (P 2 O 5). . . . 2. 0% Soluble Potash (K 2 O). . . 4. 0% Iron(Fe). . . . . 4. 0% Chelated Iron (Fe) Derived from: Potassium Orlhophosphale and Iron Citrate Complex Non-plant food ingredients Humic Substances. . . . 2. 6% Cold Water Kelp Extracts. . . . . 2. 0% Vitamin C (Ascorbic Acid). . . . . 2. 7% Vitamin B-| (Thiamine). . . 0. 3% Vitamin E (Alpha-tocopherol). . . . 0. 1% Myo-lnositol. . . . . 0. 4% Glycine. . . 0. 9%

Products Tested Lebanon/Emerald Isle Phosphoric acid. . . . 2% Soluble Potash. . . . 2% Kelp Extract. . . . 100% + Convert (a humic acid product)

Experiment Details Treatments: applied monthly at labeled rates from May to November 1. 2. 3. 4. 5. 6. Focus Launch Focus + Launch Roots program Pana. Sea Plus + Convert Untreated Control 4 replications in blocks around center circle; mowed at 2” (May-July) and 1. 5” (Aug-Nov); 4. 75 lb N/M with complete fertilizer applied May to November; diseases controlled preventively

Events August: 12 September: 29 October: 24 November: 8 Total: 73

Results: Turf Color (9 = darkest) (no differences)

Results: Percent Turf Cover (no differences)

Convert + Pana. Sea Plus Launch + Focus Launch 5/27/2004 Control Roots Focus

6/11/2004 Focus Launch Roots Launch + Focus Control Convert + Pana. Sea Plus

9/21/2004 Focus Roots Launch + Focus Control Convert + Pana. Sea Plus

Results: Physiological Health Treatment Antioxidant level: superoxide dismutase June 11 Sept 21 Photochemical efficiency Sept 22 Control 1577 b 6099 a 0. 62 ab Focus 7039 a 6540 a 0. 64 a Launch 5967 a 5167 a 0. 61 ab F+L 3784 ab 4541 a 0. 63 ab Roots 6077 a 4442 a 0. 66 a Panasea 8014 a 3654 a 0. 58 b

Results: Root and Shear Strength Treatment Root Strength (kg) Shear Strength Aug 4 Dec 2 July Control 36. 5 a 36. 8 a 26. 8 b Focus 39. 8 a 37. 0 a 38. 1 a Launch 36. 3 a 39. 8 a 33. 0 ab F+L 40. 0 a 36. 5 a 33. 3 ab Roots 36. 5 a 40. 5 a 37. 8 a Panasea 31. 8 a 36. 3 a 31. 9 ab

Summary • Under adequate fertilization, irrigation, and mild environmental conditions biostimulant programs had minor effects on Kentucky bluegrass field performance When to consider using: – Cool-season: During sod or seed establishment, especially in summer; in hot, dry years and on high profile fields with inadequate irrigation. Most likely not going to increase wear tolerance or recovery. – Bermudagrass: justification of use is most likely questionable; no effect on overwintering seen; perhaps kick -start spring re-rooting?

Can monthly granular humate (2 lb/M) reduce summer N needs on bermuda? • Soil CEC increased from 4. 3 (control) to 5. 8 • Leaf N increased from 3. 0% (control) to 3. 5% (Sept) • No other nutrient increases; no strong visual color differences over the season; no roots measured Silt loam soil with 2. 5% OM at VT

4. Amino Acids

20 essential amino acids Nitrogen is stored and transported in amino forms Proteins are chains of 100’s of amino acids, usually containing all 20 in their chains Turf

What about foliar amino acid effects? • Why might a benefit be expected? – They most likely can be absorbed by leaves = smaller than sucrose – They may conserve carbohydrate during summer stress as carbohydrates are broken down in respiration to produce chemical energy (ATP and NADPH) to make amino acids…then proteins • Good candidates formulations? Glutamine: initial product in AA production cycle; its level controls need for more or less N-assimilation Tryptophan: auxin precursor = root initiation Proline: primary osmoregulator for drought protection Turf

What are the barriers to nutrient absorption through the leaves ? • Primary ports of nutrient entry are: – Stomates (20, 000/cm 2 leaf) – Tiny pores in cuticular wax (10 billion/cm 2 leaf) • Nutrient absorption occurs by: – Diffusion – Active transport Turf

Absorption is at its peak when stomates are fully open Stomate openings are about 10 µm wide Cuticle pores are 1 nm or less = 1000 times smaller than stomate openings, but there are 106 more Urea (COH 4 N 2) is 0. 44 nm in size; small enough to move through culticle pores Factors such as salinity, heat, and water stress will cause stomates to close Turf

Sizes of molecules to go through pores • Sucrose = 1 nm, mol. wt. = 342 • Glucose = 0. 6 nm • Various inorganic ions 0. 5 to 1 nm in their hydrated forms • Amino acids have mol. wt. of 75 to 204; they should pass through cuticular pores Turf

Bentgrass foliar uptake of N sources Stiegler & Richardson, UArk, 2008 Turf

Amino acid dosing trial • • L 93 bentgrass with complete nutrient solution: 0. 25 lb N/M/month 75 F on mist bench, 3 month trial 1. Tryptophan (3 m. M/month) 2. Glutamine (3 m. M/month) 3. Control Glutamine: initial product in AA production cycle; its level controls need for more or less N-assimilation = less root energy needed for nitrate uptake Tryptophan: auxin precursor = root initiation Turf

Results: Leaf Color Turf

Photochemical Efficiency Turf

Leaf Protein content (mg/g FW) Turf

Questions and Discussion Turf