Residual effect of single biochar application on soil nutrients availability and fertilizer productivity in a mulched drip-irrigated corn field.

A 3-year field experiment was conducted to determine the impact of corn residue-derived biochar on soil organic matter (SOM), soil nutrients, corn yield and partial factor productivity of synthetic fertilizer in Hetao Irrigation District, Inner Mongolia of China. Three rates of biochar, 15 (B15), 30 (B30) and 45 (B45) t ha⁻¹, and a non-biochar control (B0) were applied to a corn field one time at the first crop growing season under film-mulched with drip-irrigation. Relative to B0, the B30 led to a significant increase in SOM at top 30 cm soil layer (15.3%) and partial factor productivity of fertilizers (12.8%) as averaged across 3 years. Amendment in B30 also increased the available nutrients in the soil (nitrogen, phosphorus and potassium), corn yield and economic benefit. In contrast, the first year showed the largest improvements for corn yield and economic benefit for B30, followed by the second year and the third year. The corn grain yield has potentially increased when the SOM and the available phosphorus were increased when compared to the available nitrogen and potassium. A single biochar amendment at the rate of 30 t ha⁻¹ can be adequate for the corn production in 3 years under dry climatic conditions. [ABSTRACT FROM AUTHOR]