Response of 15N to corn straw and biochar application in soils with different fertility levels, during corn seedling stage

Abstract

Nitrogen (N) is a necessary and the most limiting nutrient in crop production. Addition of organic amendments to the soil can improve the use of N fertilizer in crops. However, the response of N to corn straw and biochar application in soils with different fertility levels is yet not well studied. This study investigates N utilization and uptake by corn plant at seedling stage using 15N-label tracer method. Two soils with different fertility levels were selected: (i) high fertility soil (HF), and (ii) low fertility soil (LF). The HF and LF soils were amended with biochar (HFB and LFB) and corn straw (HFC and LFC) in an outdoor pot experiment. The results showed that N absorption in corn plant increased by 23.47 − 30.58% (HFB), and by 10.34 − 13.59% (HFC) compared with unamended HF soil, and increased by 26.09 − 41.53% under LFB and by 13.59 − 20.23% in LFC compared with unamended LF soil. The 15N utilization rate increased in the order of: HFB > HFC > HF and LFB > LFC > LF, illustrating that biochar and corn straw application increases the efficiency by which corn plant utilizes N. Biochar and corn straw application significantly reduce 15N losses in the soil and improve 15N utilization in corn, particular in low fertile soil.