Turfgrass establishment and persistence in urban environments can be limited by topsoil removal and subsoil compaction. A 3‐yr study (September 2013–June 2016) where tall fescue (Festuca arundinacea Schreb.) was grown with and without irrigation was conducted to compare biosolids‐based amendments with synthetic fertilizer on (i) quality and quantity of tall fescue and (ii) soil properties of a post‐development soil. The experimental design was a split plot with irrigation as the main factor and fertility treatments as the subplot factor. Fertility treatments were applied to meet the agronomic N rate of 224 kg plant available N ha−1 yr−1 for tall fescue during September 2013 to June 2015. Fertility treatments were (i) synthetic fertilizer, (ii) anaerobically digested biosolids, (iii) anaerobically digested biosolids blended with sand and sawdust, (iv) anaerobically digested biosolids blended with sand and sawdust applied at the agronomic P rate of 64 kg P ha−1 yr−1 for tall fescue and supplemented with synthetic N, and (v) composted anaerobically digested biosolids. No fertility treatments were applied from June 2015 to May 2016 to measure residual effects. Greater turfgrass yield and quality, higher soil C and macro‐ and micronutrient concentrations, and reduced soil bulk density were observed for biosolids‐blended products compared with synthetic fertilizer. Applying biosolids at the agronomic P rate did not yield desirable turfgrass quality; however, applying at the agronomic N rate continuously may lead to potential P loss if rates are not reduced.

Spectral reflectance measurements collected from hyperspectral and multispectral radiometers have the potential to be a management tool for detecting water and nutrient stress in turfgrass. Hyperspectral radiometers collect hundreds of narrowband reflectance data compared to multispectral radiometers that collect three to ten broadband reflectance data for a cheaper cost. Spectral reflectance data have been used to create vegetation indices such as the normalized difference vegetation index (NDVI) and the simple ratio vegetation index (RVI) to assess crop growth, density, and fertility. Other indices such as the water band index (WBI) (narrowband index) and green-to-red ratio index (GRI) (both broadband and narrowband index) have been proposed to predict soil moisture status in turfgrass systems. The objective of this study was to compare the value of multispectral and hyperspectral radiometers to assess soil volumetric water content (VWC) and tall fescue (Festuca arundinacea Schreb.) responses. The multispectral radiometer VI had the strongest relationships to turfgrass quality, biomass, and tissue N accumulation during the trial period (April 2017-August 2018). Soil VWC had the strongest relationship to WBI (r = 0.60), followed by GRI and NDVI (both r = 0.54) for the 0% evapotranspiration (ET). Nonlinear regression showed strong relationships at high water stress periods in each year for WBI (r = 0.69-0.79), GRI (r = 0.64-0.75), and NDVI (r = 0.58-0.79). Broadband index data collected using a mobile multispectral sensor is a cheaper alternative to hyperspectral radiometry and can provide better spatial coverage.

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The need for water conservation continues to increase as global freshwater resources dwindle. Turfgrass mangers are adapting to these concerns by implementing new tools to reduce water consumption. Time-domain reflectometer (TDR) soil moisture sensors can decrease water usage when scheduling irrigation, but nonuniformity across unsampled locations creates irrigation inefficiencies. Remote sensing data have been used to estimate soil moisture stress in turfgrass systems through the normalized difference vegetation index (NDVI). However, numerous stressors other than moisture constraints impact NDVI values. The water band index (WBI) is an alternative index that uses narrowband, near-infrared light reflectance to estimate moisture limitations within the plant canopy. The green-to-red ratio index (GRI) is a vegetation index that has been proposed as a cheaper alternative to WBI as it can be measured using digital values of visible light instead of relying on more costly hyperspectral reflectance measurements. A replicated 2 × 3 factorial experimental design was used to repeatedly measure turf canopy reflectance and soil moisture over time as soils dried. Pots of ‘007’ creeping bentgrass (CBG) and ‘Latitude 36’ hybrid bermudagrass (HBG) were grown on three soil textures: United States Golf Association (USGA) 90:10 sand, loam, and clay. Reflectance data were collected hourly between 07:00 and 19:00 using a hyperspectral radiometer and volumetric water content (VWC) data were collected continuously using an embedded soil moisture sensor from soil saturation until complete turf necrosis by drought stress. The WBI had the strongest relationship to VWC (r = 0.62) compared to GRI (r = 0.56) and NDVI (r = 0.47). The WBI and GRI identified significant moisture stress approximately 28 h earlier than NDVI (p = 0.0010). Those metrics also predicted moisture stress prior to fifty percent visual estimation of wilt (p = 0.0317), with lead times of 12 h (WBI) and 9 h (GRI). By contrast, NDVI provided 2 h of prediction time. Nonlinear regression analysis showed that WBI and GRI can be useful for predicting moisture stress of CBG and HBG grown on three different soil textures in a controlled environment.

Rehabilitating anthropogenically disturbed soils is vital to restore soil functionality and improve plant growth. Biosolids can be used to improve such soils and increase soil organic C (OC) stocks, but repeated applications of such organic byproducts may result in excess soil P. Here, we present further data that complete the observations for a 5-yr study (September 2013-October 2018) conducted on an anthropogenic soil tall fescue (Festuca arundinacea Schreb.) system. This study compared the effects of irrigation strategies (with or without irrigation during summer heat stress) and soil amendments (annual applications of biosolids products and a conventional synthetic fertilizer) for improving soil properties and tall fescue health. Biosolids amendments applied at the agronomic N rate (ANR) reduced soil bulk density at the 0-to 5-cm depth by 33-53% and at the 5-to 10-cm depth by 4-9% relative to synthetic fertilizer. Soil OC in the top 10 cm increased from 1.74 to 13.6 g OC kg −1 (i.e., +682%) over the 5-yr period for the conventionally fertilized tall fescue, and larger gains were observed in the biosolids treatments. Repeated applications of biosolids amendments at the ANR increased total P concentrations; however, biosolids containing high Fe concentrations did not increase water-soluble P compared with biosolids applied at the agronomic P rate (APR) and synthetic fertilizer after 5 yr. Biosolids amendments applied at the ANR improved tall fescue visual quality (maintained acceptable quality 86-92% of the time), clipping biomass, and leaf tissue N accumulation (P < .05). 1666wileyonlinelibrary.com/journal/csc2