Compost Application Practices Improve Quality of Turfgrass and a Degraded Urban Soil Virginia Recycling Association Annual Meeting Organics Session Hotel Roanoke May 16, 2012 Shea Dunifon, Greg Evanylo, Michael Goatley, Rory Maguire, Shan Dexin, and Xunzhong Zhang Crop and Soil Environmental Sciences Department Virginia Tech

Introduction: Disturbed Soils Urbanization contributes greatly to soil disturbance. Permanent vegetation is most effective practice to stabilize soil and reduce water impairment. Compost has been demonstrated to improve disturbed soils for vegetation establishment.

Objective To compare various compost application and turfgrass seeding practices for revegetating disturbed urban land.

Methods and Materials: field study The Summit, Lynchburg, VA Cullen Loam Slope 3-5% Study established March 2009

Initial Soil Test Analysis and Fertilizer Recommendations: March 2009 Property Soil Test Value Fertilizer Recommendations (kg ha-1) N 45 P 3 mg kg-1 78 K 80 mg kg-1 112 Ca 1221 mg kg-1 Mg >120 mg kg-1 pH 7.1 CEC 7.3 cmol(+) kg-1

Field study Treatments 1: Fertilizer and seed No cover (Control) Straw blanket Compost blanket: 0.6 cm (1/4”) depth 2: Compost - broadcast: 2.5 cm depth 3: Compost - broadcast & incorporated: 2.5 cm depth 4: Compost - broadcast & incorporated: 5.0 cm depth

Compost Source and Methods Compost source: Royal Oak Farm, Evington, VA Compost feedstock Papermill sludge Woody waste Wood ash Food processing residuals Turned windrow processing

Compost composition Parameter Result ¼ in screen size (%) 94 Moisture (g kg-1) 430 EC (dS m-1) 2.97 pH 7.9 C:N 18:1 Total Organic C (g kg-1) 300 Total N (g kg-1) 17 NO3-N (g kg-1) 9.7 P (g kg-1) 10 K (g kg-1) 14 Maturity (Solvita) Very Mature (low CO2, NH3) Small amounts of NPK… pH a little high, but not bad; Solvita test indicates it is a very stable form… Solvita – plastic vials with compost, put in absorbent papers to the vial that change colors on the paper according to CO2, NH3 levels

Applying and Incorporating Compost 1 Compost 2 Aerovate 3 Seed, roll 3/28/2009

Nutrients Recommended and Applied by Treatments K kg ha-1 Fertilizer 45 78 112 0.64 cm compost 3,200 131 98 157 2.5 cm compost 12,800 524 392 627 5.0 cm compost 25,600 1048 784 1254 Fert trt according to standard soil test results; different levels of compost are what were delivered to the plots… a lot of C is being added as well as a lot of N, but Compost N is only about 10% available (must be microbially decomposed for release); high amounts of P could be of concern… when compost is used as an amendment, is this creating a potential problem… if it ran off in surface water, possibly… the P levels can be a concern… would be more of a concern on very high sand content soils but not on heavy textured clays.

http://connect.ag.vt.edu/compostforturf/ SCT+Straw Mat (back) 0.64 cm com blanket (fore) 2.5 cm compost blanket 5 cm compost PPI 2.5 cm compost PPI Standard Fert Photo taken April 17, 2009; Plots Seeded March 24, 2009. 11 11

Visual Treatment comparisons Four weeks after establishment 6.3 cm of rainfall Straw mat Control 0.25” compost broadcast

Treatment Effects on turf biomass with time

http://connect.ag.vt.edu/compostforturf/ SCT+Straw Mat (back) Feb. 9, 2012 http://connect.ag.vt.edu/compostforturf/ Standard fertility treatment based on soil test, rep 3 SCT+Straw Mat (back) ¼” com blanket (fore) 2” compost, incorporated , Rep 3 1” compost blanket 2” compost PPI 1” compost PPI Standard Fert 1” compost, incorporated , Rep 3 Photo taken April 17, 2009; Plots Seeded March 24, 2009. July 5, 2011 CVNLA Short Course 14 14

Effects of treatments on mean seasonal turfgrass density (averaged over Time) Density assessed visually using a scale of 1 to 9 where 1 = bare ground to 9 = dense turf.

Soil properties two years after treatment applications (summer 2011) Soil Test Extractable Treatment P K TN TOC bulk density mg kg-1 soil g kg-1 soil g/cc Fertilizer 16 c 145 b 0.8b 12.2c 1.25 b 2.5 cm compost, surface 15 c 180 a 1.1 ab 18.9b 1.33 c 2.5 cm compost, incorporated 22 b 172a 1.5 a 28.2a 1.24 ab 5.0 cm compost, incorporated 26 a 202 a 1.7 a 32.0a 1.18 a In general, P – despite large amounts we don’t see a high increase in P

Conclusions Slow release of compost nitrogen likely improved turfgrass biomass with time. Incorporated compost performed better than compost blanket. Greater turfgrass density with compost than with standard fertilizer practices. Soil properties improvements: compost > fertilizer.

Thanks to our supporters National Fish and Wildlife Foundation Mark Maslow and Southern Landscape Group, Inc., Lynchburg, VA John Hicks, Augusta Co-op, Lynchburg/Bedford, VA Mr. Ken Burger, Executive Director ,The Summit, Lynchburg, VA