University of TehranIranian Journal of Soil and Water Research2008-479X511220210219Effects of Enriched Biochars on the Availability and Fractions of Phosphorus in the Saline Soils of Lake Urmia BasinEffects of Enriched Biochars on the Availability and Fractions of Phosphorus in the Saline Soils of Lake Urmia Basin317731937858010.22059/ijswr.2020.294590.668438FARoghayehMousaviDepartment of Soil Science, Faculty of Agriculture, Urmia University, Urmia, IranMirHassanRasouli-SadaghianiDepartment of Soil Science, Faculty of Agricultre, Urmia University, Urmia, Iran0000-0001-9804-4076EbrahimSepehrDepartment of Soil Science, Faculty of Agricultre, Urmia University, Urmia, Iran0000-0001-5843-0669MohsenBarinDepartment of Soil Science, Faculty of Agriculture, Urmia University, Urmia, IranMaryamKhezriDepartment of Plant Protection, Faculty of Agriculture, Urmia University, Urmia, IranJournal Article20191223In 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-H<sub>3</sub>PO<sub>4</sub>-RP)) and 2 calcareous soils with different EC (2 and 15 dSm<sup>-1</sup>). 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-H<sub>3</sub>PO<sub>4</sub>-RP treatments reduced the pH of S1and S2 soils, 0.5 and 1 unit, respectively. BC-H<sub>3</sub>PO<sub>4</sub>-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-H<sub>3</sub>PO<sub>4</sub>-RP and BC-HCl-RP treatments increased the amount of Ca<sub>2</sub>-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 Ca<sub>8</sub>-P, Al –P and Ca<sub>10</sub>-P fractions reduced significantly. Olsen-P positively and significantly correlated with Ca<sub>2</sub>-P, Fe-P, and Ca<sub>10</sub>-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.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-H<sub>3</sub>PO<sub>4</sub>-RP)) and 2 calcareous soils with different EC (2 and 15 dSm<sup>-1</sup>). 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-H<sub>3</sub>PO<sub>4</sub>-RP treatments reduced the pH of S1and S2 soils, 0.5 and 1 unit, respectively. BC-H<sub>3</sub>PO<sub>4</sub>-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-H<sub>3</sub>PO<sub>4</sub>-RP and BC-HCl-RP treatments increased the amount of Ca<sub>2</sub>-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 Ca<sub>8</sub>-P, Al –P and Ca<sub>10</sub>-P fractions reduced significantly. Olsen-P positively and significantly correlated with Ca<sub>2</sub>-P, Fe-P, and Ca<sub>10</sub>-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.https://ijswr.ut.ac.ir/article_78580_18f41d2d23fef148743c0acc858c8630.pdf