Biochar‐Mediated Controlled Release of Mineral Nitrogen From Urea Enhances Wheat Yield in Low Fertility Alkaline Soil
Maryam Mumtaz, Sajid Mahmood, Sahar Naveed, Muhammad Akhtar, Samrah Shams, Hafiza Hafsa Iqbal, Maryam Naveed, Qudsia NazirABSTRACT
Background
Nitrogen (N) losses in low‐fertility alkaline soils substantially reduce nitrogen use efficiency and limit wheat productivity. Although biochar has been widely studied as a nutrient‐retentive soil amendment; however, its potential to assist fertilizer reduction under alkaline soil conditions remains insufficiently understood.
Aim
This study evaluated the effectiveness of integrating biochar with urea to regulate soil N transformations and enhance wheat productivity in alkaline soil.
Method
A 1‐month laboratory incubation study was conducted in soil amended with biochar at 1%, 2%, and 3% (w/w) and urea at the recommended rate of 150 kg N ha −1 (0.0144 g urea jar −1 ). In a complementary pot experiment, wheat was grown in alkaline soil amended with 1% biochar combined with urea applied at 100%, 85%, and 70% of the recommended rate (0.87, 0.74, and 0.60 g urea pot −1 ), respectively.
Results
Results showed that 3% biochar was the most effective rate in the laboratory incubation, significantly lowering NH 4 + ‐N concentration and delaying its nitrification to NO 3 – ‐N; however, on the basis of the practical applicability, 1% biochar was selected for the pot experiment. Results for pot experiment revealed that wheat plants receiving 85% of the recommended urea with 1% biochar displayed improved agronomic attributes and produced higher grain yield (15.5 g pot −1 ) and total N in roots, shoots, and grain than plants supplied with 100% urea alone.
Conclusion
Overall, the results demonstrate that low biochar application rate (1%) can partially substitute for mineral N fertilizer by regulating urea‐derived N dynamics and improving wheat performance in alkaline soil.