Effect of biochar application on nitrogen use efficiency for sustainable and productive agriculture under different field crops

Abstract

This study was undertaken to investigate crop productivity, nitrogen use efficiency (AE_N, agronomic efficiency of N; ARF_N, apparent recovery fraction of N), and nitrous oxide (N2O) emission after biochar (BB, bamboo biochar) and nitrogen fertilizer (N) application in paddy and upland agricultural soils. The selected rice and Chinese cabbage were grown in the paddy soil and upland soil, respectively. Each treatment group, comprising N100% (N, 90 kg ha−1 for rice; 320 kg ha−1 for Chinese cabbage), BB + N35%, BB + N70%, and BB + N100%, was separated by a Control treatment. Overall, the increased nitrogen input and uptake resulted in improved crop growth. Under each experimental condition, soils treated with BB + N100% treatment had higher crop growth, nitrogen contents, and nitrogen uptake, as compared to other treatments. Nitrogen use efficiency was investigated independently of crop productivity results, and biochar played an important role in this assessment. In particular, both AE_N and ARF_N related to crop nutrient availability were significantly increased in the BB + N35% and BB + N70% treatments, as compared to the N100% treatment. In addition, N2O emission was reduced by decreasing the N input, and biochar contributed to N2O reduction in paddy and upland conditions. These results indicate that nitrogen use efficiency can be increased in agricultural soils supplemented with biochar application, such as paddy and upland field cultivations in South Korea. Additionally, it is considered good agricultural land management to reduce the use of inorganic fertilizers, and practice sustainable and productive agriculture.