Enhancement of Releasing Phosphorus from Bone Char in Calcareous Sandy Soil Under Applying Different Levels of Water Salinity

Abstract

The high cost of phosphate fertilizers, as well as pollution with heavy and radioactive elements, motivated us to find clean alternatives for phosphate fertilizers to conserve the environment such as bone char. Also, the groundwater used in the agricultural activity of desert soils is considered to be saline. Therefore, the specific objective of this incubation experiment was to investigate the application of bone char with different levels of water salinity on changes of phosphorus (P) availability and some soil quality indicators of calcareous sandy soil. The results of this study revealed that applying bone char (BC) combined with saline water significantly increased the available P (Olsen-P) in calcareous sandy soil compared to the control (unamended soil) and bone char with distilled water treatment. The P release from bone char increased with increasing water salinity levels. The increase of incubation time results in an increment of Olsen-P concentration at a high level of saline water. Soil pH values declined with the addition of bone char combined with saline water, while the electrical conductivity (EC) of the soil in this study increased gradually with increasing the water salinity level in the presence of bone char. The soluble sulfate (SO42−) increased by applying bone char and saline water. Based on this, we can suggest the use of bone char under the presence of saline water as an alternative to phosphate fertilizer, especially in sustainable agriculture because it is economically and environmentally friendly. The bone char can be a substitute for chemical fertilizers produced from rock phosphate.