Phosphate sludge: opportunities for use as a fertilizer in deficient.

Abstract

Phosphate sludge (PS) is an industrial by-product produced in huge quantities by the phosphate beneficiation plants in Morocco. In order to valorize this by-product, it was examined for its potential use as a soil fertilizer. The physicochemical properties, elemental and mineral content, morphological structure, and component stability of raw PS were investigated. In addition, pathogenicity, phytotoxicity, and the capacity of PS to promote plant growth in deficient sandy soil have been studied. The obtained results showed that PS was characterized by low values of moisture (2.10%), electrical conductivity (EC) (0.77 mS/cm), and organic matter (OM) (0.61%), with a slightly alkaline pH (8.20). Nevertheless, this material carried interesting content of fertilizing elements such as phosphorus (P2O5) of 20.01%, calcium (CaO) of 39.72%, and magnesium (MgO) of 2.33%. Thus, PS did not present any pathogenic or phytotoxic risk with a high increase in tomato plant growth than the control of only soil. In conclusion, the results of this study could provide the primary practical guidance for the PS application in deficient soils characterized by sandy texture.

Agro-physiological traits as biological factors to optimize organic and inorganic amendments for date palm cultivation

“…For example, in another study with tomato, the effect of PS was positive on tomato plants by improving growth in terms of biomass, SH, and NL, unlike in our study. This could be justified by the plant's variety and stage of development (Ait-El-Mokhtar et al, 2021;Haouas et al, 2021b). Another study showed an increment in potato yield and growth when a phospho-compost was applied as a biostimulant in the soil (Kammoun et al, 2017).…”

“…Phosphate ore from Morocco is processed using a series of enrichment procedures that include crushing, screening and washingwell as flotation (Boujlel et al, 2019). Phosphate sludge (PS) is produced in enormous amounts during the washing and flotation processes, with 28 million metric tons produced per year that contains about 20% of phosphorus (P 2 O 5 ) (Haouas et al, 2021b). PS is a huge economic and environmental problem that has resulted in the loss of recycled waste, the formation of dikes, the disfigurement of the landscape, and the reduction of arable areas as a result of its accumulation (Haouas et al, 2020).…”

“…PS is a huge economic and environmental problem that has resulted in the loss of recycled waste, the formation of dikes, the disfigurement of the landscape, and the reduction of arable areas as a result of its accumulation (Haouas et al, 2020). Until now, little research has tried to establish acceptable methods for PS valorisation, such as composting (Haouas et al, 2021b;Mobaligh et al, 2021). PS as a phosphate rock by-product has the potential to be a long-term, low-cost, and always-available substrate for rehabilitating deficient soils.…”