Phosphorus-Enriched Rice Husk Biochar Affected Growth and Mineral Nutrition of Wheat and Its Residual Effects on Maize Production

Biochar has proven to increase phosphorus (P) content in acidic soils; since biochar has alkaline character, its long-term applications may have a negative effect on the availability of P and other elements in alkaline soils. Therefore, this study aimed to study a newly developed P fertilizer, phosphorus-enriched biochar (PEB), to evaluate and compare for its agronomic performance on wheat and maize. Rice husk biochar was enriched with concentrated phosphoric acid (PA), (500/84: w/v ). X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to determine PEB’s functional and structural properties. Under controlled conditions, a greenhouse experiment was conducted with wheat followed by maize to determine the main and residual effects of P. The four treatments were control (no P), triple superphosphate (TSP), PA, and PEB (200 mg·P·kg -1 ). The experiment was designed using completely randomized design with five replications. Incorporation of PEB in the form of biochar (BC) integrated with PA significantly increased plant dry weight in both crops. PEB resulted in the highest P concentration in wheat (6.38 g kg -1 ). Similarly, the residual effects were seen in maize (3.18 g kg -1 ). In both plants, treatments did not significantly affect N and K concentrations. Calcium concentration in the wheat plants increased significantly. Different P sources had different effects on Fe (wheat remained un-changed; decreased in maize), Si, Zn, Cu, and Mn (decreased in both plants). Biochar enriched with PA decreased the soil pH and increased the P concentration in soil, and plant, hence, can replace inorganic P fertilizers as an alternative and in eco-friendly manner. Additional experiments are required for better understanding the main and residual effects of the designed fertilizer. This will enable us to find its effectiveness in growth and P nutrition in different types of soils and crops, which could sustain productivity in alkaline soils.