Soil phosphorus fractionation after co-applying biochar and paper mill biosolids

Abstract

In recent decades, there has been a growing interest in the recycling of organic materials such as paper mill biosolids (PB) and biochar for use as soil amendments. However, the benefits of co-application of PB and biochar and its effects on soil phosphorus (P) availability remain unknown. An incubation study was conducted on two acidic soils to assess the effect of two PB types (2.5% w/w) co-applied with three rates (0%, 2.5%, and 5% w/w) of pine (Pinus strobus L.) biochar on soil P fractions. An unfertilized control and a mineral NP fertilizer were used as a reference. Soil P fractions were determined by Hedley procedure after 2 and 16 wk of incubation. Material fractionation indicated that the PB containing the highest total P and the lowest Al content had the highest proportion of labile P, whereas most P in the biochar was in a stable form. The incubation study revealed that the P-rich PB increased P availability in both soils to a level comparable to mineral fertilizer at the end of the incubation. The addition of biochar to PB, however, did not affect soil P availability, but the highest rate induced a conversion of P fixed to Al and Fe oxides towards recalcitrant forms, particularly in the sandy loam soil. We conclude that co-applying biochar and PB could be more beneficial than application biochar alone and soils amended with such a mixture would be expected to release part of their P slowly over a longer period of time.

Biochar in temperate soils: opportunities and challenges

“…Although biochar amendments can improve soil fertility and N, P, K, and total C content (Biederman and Harpole 2013;Mukherjee et al 2014), this C-rich material is generally not considered as a fertilizer source. The co-application with an organic or inorganic source of fertilizer is often recommended to increase the availability of nutrients in agricultural soil (Abedin 2018;Sánchez-Monedero et al 2019;Abedin and Unc 2020;Manirakiza et al 2020;Omara et al 2020;Ziadi et al 2020). For example, Abedin (2018) added biochar derived from sugar maple (Acer saccharum) at a rate of 20 Mg C ha -1 with half or the full recommended dose of fertilizers and fishmeal.…”

Amelioration of dry land suboptimal using biochar and compost to improve soil physical properties and soybean yield

“…Right now, using biochar and compost together is seen as a highly effective and sustainable agricultural approach to reduce environmental risks and boost soil fertility and crop yields [4,5]. Recent research suggests that biochar is most beneficial in enhancing soil qualities *Corresponding author: endriani@unja.ac.id when it is used alongside or processed together with other soil amendments like biosolids, paper mill sludge, manure, and compost [6][7][8][9].…”

Biochar amendments for sustainable soil management

“…Research also shows that biochar is most effective in improving soil properties when it is combined or co-processed with another soil amendment such as compost, manure, paper mill sludge, or biosolids (Manirakiza et al 2022;Ziadi et al 2022;Hangs et al 2022). Although the majority of biochar research has focused on soil and field crops, there is an emerging body of literature that examines the potential for biochar use in the horticultural industry for both fruit and vegetable production (Messiga et al 2022a;Shang et al 2022).…”