Enhancing the Availability of Potassium in New Egyptian Soils using Biochar Produced from Olive Stone Waste

Abstract

The warming phenomenon is one of the most difficult challenges of the times. Agricultural waste decomposition contributes to global warming due to the increase in greenhouse gases. Carbon sequestering is used to reduce greenhouse gases to mitigate the warming phenomenon. Applying biochar is one of the most important tools for sequestering carbon in the soil for hundreds to thousands of years. Paper aims to produce olive stone biochar (OSB) and apply it to soils to study its effect on soil properties and the status of K (Quantity/Intensity of K). Biochar was produced from olive stone waste at 650°C and applied at rates of 0, 1, 2, and 5% in two investigated soils (sandy and calcareous) to study its effects on soil properties and growth of the wheat plants. Results of biochar analysis indicated that it possesses several functional groups and essential elements (N, P, and K), a large surface area (394.25 m2 g-1), and an average fine diameter (0.8 µm). The application of OSB improved several soil properties, including water holding capacity, %porosity, bulk density, cation exchange capacity, and availability of some nutrients, especially potassium. Additionally, it increased the soluble-K and ammonium acetate (NH4OAc-K) levels in the investigated soils. The potential buffering capacity of K (PBCK), activity ratio of K (ARK), and labile K (KL) were also enhanced. Moreover, OSB application improved the wheat plant’s height, root depth, dry matter, and NPK content. Therefore, we concluded that biochar is beneficial for sequestering carbon for the long-term and improving soil fertility.