Biochar‐Based Fertilizer Is Cost‐Effective, Reduces Nutrient Input and Improves Nutrient Use Efficiency Without Decreasing Yield

ABSTRACT Developing high‐efficiency fertilizers with less environmental footprint is essential for sustainable cropping systems. This study evaluated a biochar mineral complex (BMC) to reduce nutrient leaching and increase nutrient use efficiency (NUE), yield, and economic productivity. The novel BMC was produced by pyrolyzing minerals and organic feedstocks. The BMC was co‐applied with organic fertilizers to potting media using two methods: (1) rotary incorporation at 10%, 20%, and 50% rates, and (2) applied as a layer in the middle of the pot at 50% rate, and compared with synthetic and organic fertilizer controls. Nutrient availability and leaching, NUE, crop biomass, yield, and net income were examined. The BMC‐layered at 50% rate with organic fertilizer improved nitrogen (N) and potassium (K) use efficiencies by +103% and +158%, respectively, compared with synthetic fertilizer and N, phosphorus (P), and K use efficiencies by +60%, +134%, and +92%, respectively, compared with organic fertilizer. Applying BMC at 50% rate reduced potting costs by 12% and 20% compared with organic and synthetic fertilizers, respectively. The BMC‐layered at 50% rate increased net income than synthetic fertilizer, achieving comparable income to organic fertilizer. Balanced nutrient fluxes in the rhizosphere increased NUE, sustained plant growth, and yielded results comparable to synthetic and organic fertilizers despite lower input rates. Co‐applying BMC‐layered at 50% rate reduced nutrient leaching and led to increased NUE by improving CEC, physical entrapment, and surface bonding within the rhizosphere compared with incorporation methods. Therefore, applying a BMC‐layer at the 50% rate is recommended to maximize nutrient use without decreasing yield within fertilizer‐intensive and soilless cropping systems.