Soil Phosphorus Fractionation as Affected by Paper Mill Biosolids Applied to Soils of Contrasting Properties

Abstract

Industrial by-products such as paper mill biosolids (PBs) have been used as fertilizers and amendments in agriculture for many decades. However, their content of plant essential nutrients including phosphorus (P) varies largely with sources, and availability of these nutrients once applied to soil still remains unknown. Five PBs differing in their C/N ratio (12-47) were used in an incubation study to assess the P forms and availability from both PBs and PB-amended soils. Biosolids were added to three contrasting soils varying in texture and pH in 500-ml jars at the rate of 50 Mg wet ha −1 , supplying between 45 and 112 kg total P ha −1. An unfertilized control and a mineral NP treatment (30 kg P ha −1) were also included. Biosolids and soil P fractions were determined by a modified Hedley fractionation method following 2 and 16 weeks of incubation. Phosphorus forms in PBs varied across type of materials with labile P ranging from 20 to 72% and organic P (Po) ranging from 28 to 66% of total P. Soil incubated with PB showed changes in all P fractions due to amendment, soil type, and duration of incubation. Resin-P and labile P, the most available forms, were significantly higher with addition of high PB-P content. Soil labile P represented up to 50% of total P added by PB. Overall, most inorganic P (Pi) fractions and labile P further increased with incubation duration. Close relationships were established between resin-P and labile P content in PB and the increases of those fractions in incubated soils, notably after 2 weeks. The P recovery as labile P represented on average 34% of total P added or 68% in terms of mineral P. We concluded that PB could be used as an efficient source of P for fertilizing crops.

Intercropping of Leguminous and Non-Leguminous Desert Plant Species Does Not Facilitate Phosphorus Mineralization and Plant Nutrition

“…Similarly, we found that the soil P fraction pool across these different plant community structures and soil horizon depths was dominated by the stable Ca-bound P fraction (HCl-P), which comprised 85.5% of the total soil P budget in the A horizon and 84.9% in the B horizon of the soil. The resin-extractable P represents the most labile pool of Pi and Po, followed by the bicarbonate-extractable Pi and Po [83,84]. The A. sparsifolia monoculture could absorb labile P and increase the proportions of resin-extractable P and bicarbonate-extractable Pi in the soil B horizon better than the K. caspia monoculture or intercropped plots (Figure 3).…”

Growth and foliar nutrition of a hybrid poplar clone following the application of a mixture of papermill biosolids and lime mud

“…The use of papermill biosolids could be an attractive soil amendment alternative in agriculture and forestry. They are rich in Ca, also contain N, P and K (but in lesser amount than municipal biosolids), and due to a high fiber content they can augment soil structure, organic carbon and cation exchange capacity (Chantigny et al 1999;Camberato et al 2006, Zhang et al 2020. Papermill biosolids potentially minimize environmental risks compared to municipal biosolids because they contain less heavy metals than municipal biosolids and do not lead to critical levels in plants after they are applied on agricultural fields (Gagnon et al 2013).…”