Different rates of biochar application change ¹⁵N retention in soil and ¹⁵N utilization by maize

Abstract

Biochar application to soil may impact soil nitrogen (N) dynamics, but the effects on N uptake and utilization by crop remain largely unknown, especially the effects of the rate of biochar application. To investigate the effects of biochar on soil 15 N retention rate and 15 N utilization efficiency (15 NUE) by maize, a six-month 15 N isotope tracer technique combined with in situ pot experiment was conducted in Mollisol. The experiment included four treatments: no biochar applied (CK) and biochar applied at the rates of 12 t ha −1 (P12), 24 t ha −1 (P24) and 48 t ha −1 soil (P48). Compared with CK, biochar application reduced soil bulk density and 15 N loss rate, and significantly improved total N and 15 N retention amount in the 0-30 cm soil depth. The P24 treatment had the largest increase in 15 N retention rate throughout the 0-40 cm depth. After biochar application, the 15 N uptake and 15 NUE were significantly increased in the grain and leaf, which promoted grain yields. Contrary to this, the P48 treatment appeared to lower 15 N uptake and 15 NUE compared with P12 and P24. In conclusion, biochar application improves the potential of the soil to retain N and the improvement in 15 N uptake and utilization are more pronounced in maize leaves and grain. Moreover, biochar application promotes 15 N utilization in maize plant and improves maize yield. However, when biochar application rate is high (i.e. P48 treatment), the 15 N retention by the soil and 15 N utilization by the maize are reduced markedly compared with P12 and P24.

Biochar for sustainable soil management

“…Biochar application increases soil organic content in soil, resulting in carbon sequestration (Zhao, Lin, et al, 2020). Biochar addition could alleviate N 2 O emission induced by straw return (Li et al., 2020); however, the biochar dosage needs to be optimized because high biochar dosage was found to significantly reduce nitrogen retention and nitrogen usage by crops (Ma et al., 2020). It is still unclear whether or not biochar can play a critical role in the current global battle against climate change.…”

Integrated Life Cycle Assessment for Sustainable Remediation of Contaminated Agricultural Soil in China

“…Although the longevity of various stabilization reagents at field is still not well understood, we do know that it is affected by physical, chemical, and biological forces, including UV light, wet–dry cycling, freeze-thaw cycling, and microbial colonization. , Robust studies must be carried out to determine their longevity in order to determine whether such remediation materials can be claimed as “green remediation material” . Moreover, the application of biochar can affect nitrogen retention and greenhouse gases, for example, N 2 O and CH 4 emissions; , our tertiary impact estimation method can be used to capture this potentially significant impact over a 50 year time horizon.…”

Application of Corn Straw and Woody Peat to Improve the Absorption and Utilization of 15N-Urea by Maize

“…The utilization efficiency of 15 N fertilizer by maize ( 15 NUR%), and the residual 15 N remained in soil were calculated according to [23].…”