Dolomite and Micronutrient Fertilizer Affect Phosphorus Fate in Pine Bark Substrate used for Containerized Nursery Crop Production

Abstract

Dolomite and a micronutrient fertilizer are routinely incorporated into a pine bark-based soilless substrate when producing containerized nursery crops, yet the effect of these amendments on phosphorus (P) is not well understood. The objective of this research was to determine the effect of dolomite and micronutrient fertilizer amendments on P partitioning among four P fractions (i.e., orthophosphate-P [OP], non-orthophosphate dissolved P [nODP], total dissolved P [TDP], and particulate P [PP]) and to model potential P species in leachate of pine bark substrate. Amendment treatments incorporated into bark at experiment initiation included (1) a control (no fertilizer, dolomite, or micronutrient fertilizer), (2) controlled-release fertilizer (CrF), (3) CrF and dolomite, (4) CrF and micronutrient fertilizer, or (5) CrF, dolomite, and micronutrient fertilizer. Phosphorus fractions in leachate of irrigated pine bark columns were determined at eight sampling times over 48 days. Amending pine bark with dolomite and micronutrient fertilizer reduced leachate OP concentrations by 70% when averaged across sampling dates primarily due to retention of OP in the substrate by dolomite. The nODP fraction was unaffected by amendments, and the response of TDP was similar to that of OP. Particulate P was present throughout the study and was strongly correlated particulate Fe and DOC concentrations. Visual MInTEq indicated MnHPO 4 and Ca 5 (PO 4) 3 (OH) were consistently saturated with respect to their solid phase in treatments containing CrF. results of this study suggest amending pine bark with dolomite and micronutrients is a best management practice for reducing P leaching from containerized nurseries.

Storage Procedures Affect pH, Electrical Conductivity, and Nutrient Concentrations of Pour-through Leachate from Pine Bark and Peat-based Substrates

“…1, suggesting Ca 2+ is less stable in extracts from a peatbased compared with a pine bark-based substrate over time. Precipitation of Ca 2+ compounds such as hydroxyapatite [Ca 5 (PO 4 ) 3 OH] may have been partially responsible for lower Ca 2+ concentrations than the control at day 30 (Shreckhise et al, 2019). As was also discussed for Expt.…”

“…Phosphate-P (PO 4 3--P) concentration was 1.32 mg • L -1 at day 0 (Table 2) and remained stable through day 7 regardless of filtration or storage temperature. PO 4 3--P decreased (<11%) by day 30 in samples stored at RM, probably due to algal or bacterial uptake, the formation of insoluble phosphate precipitates (e.g., MnHPO 4 and Ca 5 [PO 4 ] 3 OH), or both (Gardolinski et al, 2001;Lambert et al, 1992;Shreckhise et al, 2019). PO 4 3--P concentrations generally remained stable for the duration of the experiment (30 d) when stored at RF or FZ; filtered RF was an exception, with a 5% higher PO 4 3--P concentration than the control.…”

Influence of Flue Gas Desulfurization Gypsum on Phosphorus Loss from a Horticultural Growth Medium

“…Reductions in P loss could be a result of gypsum reacting with soluble P to form insoluble Ca-P complexes [37], such as hydroxyapatite and fluorapatite [38]. Shreckhise et al [39] evaluate the influence of using dolomite on the reduction in P loss from nursey containers. Similar to our results, they observed reduction in P loss to leaching with the addition of dolomite when compared to fertilized substrate with no amendments.…”

Utilización de polvo de roca basáltica en comparación con la dolomita para ajustar el pH de un sustrato a base de compost de corteza de pino y su respuesta en la disponibilidad de nutrientes

“…Se sugiere la adición de calcáreos: el carbonato de calcio (CaCO 3 ) y la dolomita [CaMg(CO 3 ) 2 ] son los principales productos utilizados en la agricultura para incrementar el valor de pH (Altland y Jeong, 2016). En particular, para la corrección de sustratos a base de corteza de pino, la dolomita es la más empleada (Shreckhise et al, 2019), debido a que aporta Ca y Mg adicionales que absorbe la planta.…”