Biosolids and biochar application effects on bahiagrass herbage accumulation and nutritive value

Abstract

Pastures represent the major cropping system where biosolids are recycled in Florida, yet limited information is available documenting the agronomic benefits of biosolids recycling programs. A 2-yr experiment evaluated bahiagrass (Paspalum notatum Flügge) responses to application of biosolids and inorganic fertilizer applied either alone or in combination with biochar. Our hypothesis was that biochar could alter soil N and P dynamics, thus, affecting crop nutrient use efficiency. Treatments were a factorial arrangement of four fertilizer sources (inorganic fertilizer, thermally dried Class AA biosolids, aerobically digested Class B biosolids, and anaerobically digested Class B biosolids; surface-applied at 160 kg plant available N ha −1 yr −1 ) with or without biochar (applied at 1% wt basis). Bahiagrass total annual herbage accumulation was similar for biosolids and inorganic fertilizer treatments in 2017; however, inorganic fertilizer and aerobically digested Class B biosolids increased total annual herbage accumulation by as much as ∼29% relative to other sources in 2018. Biosolids and inorganic fertilizer increased bahiagrass crude protein (CP) concentration by as much as ∼22 and ∼39% in 2017 and 2018, respectively, compared to unfertilized treatment. No treatment effects were observed on in vitro digestible organic matter (IVDOM) concentration in 2017; however, in 2018 biosolids resulted in greater IVDOM than inorganic fertilizer. Data suggested no benefit of biochar on bahiagrass responses.Bahiagrass tissue mineral concentrations in both biosolids and inorganic fertilizer treatments were generally within sufficient range for optimum plant growth. Biosolids can be a viable alternative for sustainable bahiagrass production while reducing the dependence on inorganic fertilizer.Bahiagrass is a warm-season perennial grass species used for grazing and hay production in the southeastern United Abbreviations: AOAC, Association of Official Agricultural Chemists; CP, crude protein; IVDOM, in vitro digestible organic matter; PAN, plant available nitrogen.

Biochar impacts on nutrient dynamics in a subtropical grassland soil: 1. Nitrogen and phosphorus leaching

“…The significant drought period experienced in spring 2017 may have limited forage growth during the 2017 growing season. Data from previous published work conducted in the same experimental area confirmed that forage production was 18–21% greater in the 2018 than in the 2017 growing season (Lu et al., 2020). Results obtained in the current study were consistent with previous studies in the region, suggesting greater N offsite transport from agricultural fields mainly occurred during the months of June to October, which coincide with the rainy season in Florida (Zhang et al., 2007).…”

“…In Florida, biosolids are mainly applied to perennial pastures as an alternative source of nutrients (Florida Department of Environmental Protection, 2013). The agronomic benefits associated with land application of biosolids to pastures such as increased forage production and nutritive value are extensively documented in the scientific literature (Adjei & Rechcigl, 2002; Avery et al., 2018; Cogger, Bary, Myhre, & Fortuna, 2013; Corrêa & Silva, 2016; Lu, Silveira, Vendramini, Erickson, & Li, 2020). However, public concerns regarding the potential impacts of biosolids on water quality have prompted recent revisions in biosolids regulations in Florida, which resulted in a significant reduction in the area where biosolids can be land applied in the state.…”

Biochar and nitrogen application rates alter some forage and soil minerals concentrations and soil leachate quality in a semiarid mixed grassland system

“…The literature is less than compelling for a positive response of plant tissue minerals to biochar application rate. For example, in both contrast and concurrence to mineral responses to biochar application rate in this study, Keith et al, (2016) and Lu et al, (2020) reported no effects of biochar amendment on tissue minerals (N, P, K, S, Ca, Mg, Fe, Mn, Zn and Cu) concentrations of mixed pasture biomass and bahiagrass (Paspalum notatum Flügge), respectively. Further, Lentz and Ippolito (2012) reported no effect of biochar application on corn silage nutrient concentrations in the first year (2009) but in the second year of their study (2010) biochar decreased silage Cu, S and total N concentrations.…”

Biochar application on commercial field crops using farm-scale equipmen

“…Biochar application produces a variable growth response and nutrient composition in perennial forages. For example, Lu et al (2020) found that adding biosolids increased the crude protein content of perennial bahiagrass (Paspalum notatum Flügge) by up to 39% compared to the unamended control. Still, crude protein values of this forage were the same in biochar and inorganic fertilizer-treated plots in their experiment.…”