Dados do Trabalho

Título

ACIDIFICATION AND LOCALIZED APPLICATION: STRATEGIES TO INCREASE P USE EFFICIENCY FROM BIOWASTES

Resumo

Increasing prices of mineral P fertilizers enhances the need for efficient recycling of P-rich biomaterials. Based on that, we proposed the integration of localized application and acidification as two approaches to increase the P use efficiency of biowastes. For that, we selected biogas digestate (BGF), meat and bone meal (MBM) in a rhizobox experiment with wheat grown for 28 days. Both biomaterials were applied as P fertilizers placed below the seeds, untreated and acidified (based on preliminary experiments). In another experimental setup, the same biomaterials were incubated (without plants) in rhizoboxes for 14 days. After incubation, diffusive gradients in thin gels (DGT) were deployed in the fertilizer-soil interface to assess P diffusion from the biomaterial to the soil. A parallel setup was equipped with planar optodes for 21 days to visualize pH changes in the placement zone and in the surrounding soil. The placement of BGF created a 'hot-spot' for root proliferation. On the other hand, no root growth was observed in the placed acidified BGF, in which roots proliferated in the surrounding of the placement zone. Images from DGT indicate that considerable amounts of P were released from the acidified BGF to the soil. In the case of MBM, both untreated and acidified created an ammonium toxicity zone in the soil surrounding the placement zone. DGT imaging demonstrated that for the MBM untreated the P remained in the placement zone, whereas for the acidified, it was substantially released to the soil. For both MBM (2.84 vs. 1.72 mg P) and BGF (4.56 vs. 2.69 mg), the acidification significantly increased the P uptake compared to the untreated. However, only for MBM there was a significant increase on shoots biomass (1.37 vs 0.90 g per plant). Based on these results we conclude that acidification can be an approach to increase P use efficiency when biomaterials are placed in the soil.

Palavras-chave

meat and bone meal; biogas digestate; nutrient recycling

Instituição financiadora

This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No.860127