Effects of Enriched Biochars on the Availability and Fractions of Phosphorus in the Saline Soils of Lake Urmia Basin
2021
Mousavi, Roghayeh | Rasouli-Sadaghiani, MirHassan | Sepehr, Ebrahim | Barin, Mohsen | Khezri, Maryam
In order to reduce the problems of biochar application in calcareous soils, by changing the surface properties of apple-grape biochar by phosphoric and chloric acids, the effects of enriched biochars on the fraction of phosphorus (P) forms in saline soils of Lake Urmia was investigated as a factorial incubation experiment in a completely randomized design with two factors: fertilizer treatments (control (Cont), biochar (BC), phosphate fertilizer (TSP), Biochar-Rock phosphate (BC-RP) and enriched-biochar (EB) types (BC-HCl-RP and BC-H3PO4-RP)) and 2 calcareous soils with different EC (2 and 15 dSm-1). Olsen-P, pH and different forms of inorganic P were determined by sequential extraction method at 7, 30 and 60 days of incubation. The results showed that on average, the BC-HCl-RP and BC-H3PO4-RP treatments reduced the pH of S1and S2 soils, 0.5 and 1 unit, respectively. BC-H3PO4-RP and BC-HCl-RP treatments increased Olsen-P of S1 soil from 6.7 to 57.5 and 55.5 mgkg-1 and soil S2 from 7.4 mgkg-1 to 71.3 and 62 mgkg-1, respectively. Enriched biochars significantly (p <0.01) altered the distribution and amount of inorganic P forms. Thus, BC-H3PO4-RP and BC-HCl-RP treatments increased the amount of Ca2-P fraction in the S1 soil by 2.9 and 2.6 times and in the S2 soils by 1.06 and 0.97 times, respectively. However, the amounts of Ca8-P, Al –P and Ca10-P fractions reduced significantly. Olsen-P positively and significantly correlated with Ca2-P, Fe-P, and Ca10-P fractions and positively but not significantly with the Al-P fraction, suggesting that in the extraction of Olsen-P, phosphorus is released from these mineral fractions. In general, EBs application may cause P to remain in the plant-available forms over the time. Therefore, it can help to improve P nutrition, reduce salinity stress, and eliminate the common problems of biochar application in these soils.
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