Applied Soil Ecology 144 (2019) 31–41 Contents lists available at ScienceDirect Applied Soil Ecology journal homepage: www.elsevier.com/locate/apsoil Composted biosolids for golf course turfgrass management: Impacts on the soil microbiome and nutrient cycling T ⁎ N.E. Staceya, R.W. Lewisb, J.R. Davenportb,c, T.S. Sullivanb, a Center for Sustaining Agriculture and Natural Resources, Washington State University, 2606 W. Pioneer, Puyallup, WA 98371, United States of America b Department of Crop and Soil Sciences, PO Box 646420, Washington State University, Pullman, WA 99164, United States of America c Irrigated Agriculture Research and Extension Center, 24106 N Bunn Road, Prosser, WA 99350, United States of America ARTICLE INFO ABSTRACT Keywords: Land application of biosolids is a primary means of recycling human waste products globally; however, because Soil microbiome biosolids are also heavily enriched with nutrients and pollutants, it is necessary to consider the environmental Composted biosolids impacts of land applications in various agro-ecosystems. To reduce costs and divert waste, biosolids from Joint Land applications Base Lewis-McChord, a military installation south of Tacoma, WA, USA, are composted with organic materials Turfgrass derived from the base itself. The potential for turfgrass management using the composted biosolids was tested in Turfgrass N management a field study at the military recreation facility, Eagles Pride golf course. The composted biosolids were surface- Fairway −1 Nutrient recycling amended to golf course fairways (n = 3) at a rate of 46 Mg ha , in split applications, fall and spring, over two years, 2015 and 2016. Soil bacterial and fungal community responses were evaluated in amended and un- amended soils from each fairway, along with soil chemical properties, including soil pH, total carbon (C), total nitrogen (N), and the C:N ratio. Soil microbial community analysis on soils sampled pre- and post-amendment did not demonstrate changes in community structure as a result of the composted biosolids application. Differences observed in soil microbial community structure appears to reflect edaphic and vegetative differences between fairways. Generally, correlations between soil properties and bacterial community OTUs were stronger than those with fungal OTUs, and predicted bacterial community functional analysis revealed several KO term groups were significantly correlated with soil TC and TN. Turfgrass biomass was unaffected, while leaf tissue N was increased by 4.5 and 10.6% in 2015 and 2016, respectively. These results suggest that amendment with composted biosolids does not strongly impact microbial communities across two years; however, long-term amendment could have affects that are not detected during this short-term study. 1. Introduction standards (Al-Rajab et al., 2015; Fytili and Zabaniotou, 2008; Lloret et al., 2016; Veeresh et al., 2003). But, due to food safety concerns, use As a byproduct of the wastewater treatment process, in 2007 bio- of biosolids in agroecosystems remains limited (Latare et al., 2014; − solids production in the U.S. was estimated at 7.18 MT year 1 (Beech Udeigwe et al., 2015). It has been proposed that combining biosolids et al., 2007), and has increased steadily since that time. Land applica- with organic amendments may mitigate some environmental impacts of tion is the internationally preferred biosolids disposal method based biosolids land applications (Paramashivam et al., 2017), and could primarily on the potential to recycle plant nutrients and improve soil create a suitable soil and nutrient management product for use in non- physical properties (European Commission, 2016; Sharma et al., 2017; food specialty crops, such as golf course turfgrass. USEPA, 2009). However, the potential for environmental degradation is In 2002, there were 15,827 golf courses in operation across the a major concern, as environmental contamination, and surface or United States alone (Haydu et al., 2008). An 18-hole golf course oc- groundwater pollution can result from improper land application from cupies a median of 60.7 ha, of which 38.4 ha is actively maintained a variety of organic and inorganic pollutants present in municipal turfgrass (GCSAA, 2017), though different playing areas (e.g., fairways, biosolids (Clarke and Smith, 2011; Edwards et al., 2009; Topp et al., greens, or roughs) are each subject to varying management intensities 2008). Therefore, biosolids land application is well-studied and inter- (Throssell et al., 2009; USEPA, 2013). The production of high-quality national regulatory bodies have determined local application limits and turfgrass, driven by aesthetics, playing conditions, and plant health, ⁎ Corresponding author. E-mail address: [email protected] (T.S. Sullivan). https://doi.org/10.1016/j.apsoil.2019.06.006 Received 26 October 2018; Received in revised form 24 May 2019; Accepted 10 June 2019 Available online 11 July 2019 0929-1393/ © 2019 Elsevier B.V. All rights reserved. N.E. Stacey, et al. Applied Soil Ecology 144 (2019) 31–41 typically includes intensive use of irrigation, fertilization, and pesti- Table 1 cides (Beard, 2002; Fry et al., 2013; Gillette et al., 2016; Hejl et al., Listed are chemical properties for as-received (AR) and dry weight (DW) 2016; King et al., 2001; Lyman et al., 2007; Mangiafico and Guillard, composted biosolids used in 2013 and 2016, along with methods of analysis. 2007; Slavens and Petrovic, 2012; Wong and Haith, 2013). Characteristics Year Methodsa The composition and function of the soil microbial community largely controls organic matter decomposition, carbon (C) sequestra- 2013 2016 tion, soil aggregation, and many other aspects of soil health and eco- AR DW AR DW system function (Rillig and Mummey, 2006; Six et al., 2006; Zhou et al., 2011). In particular, the rate of nitrogen (N) cycling and the size of N Moisture (%) 53 – 44 – 03.09A (70 C) pools are heavily moderated by soil microorganisms (Elser et al., 2007; Solids (%) 47 – 56 – 03.09A (70 C) pH 6.3 – 5.8 – 04.11A (1:5 w:w) Hayatsu et al., 2008), which consequently moderate plant productivity − E.C. (dS m 1) 0.087 0.186 0.189 0.335 04.10A (1:5 w:w) in agro-ecosystems including turfgrass systems (Gai et al., 2016; Sabagh Organic C (%) 12.2 26.1 17.9 31.8 04.01A et al., 2017). Many microbial taxa and the related enzymatic systems Organic matter (%) 22.9 49.1 29.5 52.4 05.07A responsible for key transformations in the N cycle are well studied Ash (%) 23.7 50.9 26.8 47.6 03.02 b (Levy-Booth et al., 2014; Regan et al., 2017); however examination of C:N ratio – 14 – 14 Total N (%) 0.87 1.87 1.28 2.28 04.02D the microbial community in its entirety (structure, composition, and − Ammonium-N (mg kg 1) 222 476 47 83 05.02C “ ” − diversity comprising the microbiome ) is often a better predictor of Nitrate-N (mg kg 1) 193 414 539 957 04.02B − overall soil function than any individual enzyme or one specific taxon Chloride (mg kg 1) 605 1297 337 598 04.12D − (Kaiser et al., 2014). In fact, shifts in the microbiome have been linked Sulfate-S (mg kg 1) 114 244 568 1008 04.12D − B (mg kg 1) 8.1 17.3 8 14 04.12B/04.14A to global scale ecosystem processes (Wagg et al., 2014) and their in- − Zn (mg kg 1) 192 412 103 183 04.12B/04.14A − clusion in biogeochemical modeling enhances predictive power dra- Cu (mg kg 1) 106 227 60 107 04.12B/04.14A − matically (Powell et al., 2015). Fe (mg kg 1) 6236 13,365 5026 8923 04.12B/04.14A − Previous research has shown that land-use change (conversion from As (mg kg 1) – 3.9 – 6.1 04.12B/04.14A − Cd (mg kg 1) – 1.6 – 0.8 04.12B/04.14A a forest to a turfgrass system) can be a dominant force shaping soil − Cr (mg kg 1) – 29.6 – 4.2 04.12B/04.14A microbial communities in turfgrass systems (Bartlett et al., 2007; Yao − Co (mg kg 1) – 4.3 – 17.7 04.12B/04.14A − et al., 2006). Yet, very little is known concerning what occurs in the Pb (mg kg 1) – 144 – 23 04.12B/04.14A − turfgrass microbial community as a result of the varying and highly Hg (mg kg 1) – 0.71 – 0.68 04.12B/04.14A − intensive management regimes of golf course turfgrass systems, parti- Mo (mg kg 1) – 8.5 – 7.4 04.12B/04.14A − Ni (mg kg 1) – 19 – 11.2 04.12B/04.14A cularly with the addition of composted biosolids (CB). − Se (mg kg 1) – 0.8 ––04.12B/04.14A In this study, next-generation sequencing (NGS) was used to in- vestigate bacterial and fungal soil community responses to CB amend- a Method codes refer to Test Methods for the Examination of Composting and ments in a golf course turfgrass system located in the high-rainfall re- Compost (TMECC) (Leege et al., 2002), unless otherwise noted. gion of the Pacific Northwest (PNW). Further, these data were used to b Total nitrogen and organic carbon, combustion method (Gavlak et al., examine bacterial community functional response as a potential pre- 2005). dictor of nutrient management strategies in response to CB additions. − Surface applications of CB to a golf course fairway were hypothesized to 46 Mg ha 1 to meet a target depth of 0.635 cm per application and an result in altered soil microbial community structure and predicted C annual depth of 1.27 cm. Amendments were applied in July and and N cycling functions. September of 2015, as well as April and September of 2016, and sam- ples were collected 28 days following amendment. CB were surface 2. Materials and methods applied using a pull-behind Dakota turf tender 410 (Grand Forks, ND) and immediately brushed into the turfgrass canopy after each appli- 2.1.