Maize stover biochar increases urea ( 15 N isotope) retention in soils but does not promote its acquisition by plants during a 4-year pot experiment

Abstract

382Biochar as a soil amendment has been shown to improve soil quality and crop growth. However, biochar's effect on urea-N use efficiency in long term is not well elucidated. Here we studied urea-N ( 15 N isotope) allocation in plants and soil in the presence of maize (Zea mays L.) stover biochar (equivalent to 46 t ha -1 ) during a 4-yr pot trial. Results showed that biochar only increased maize biomass (about 9%) with high amount of urea addition, which indicates the increased maize dry weight by biochar application could be attributed to synergistic effects between biochar and urea. Soil total N contents and fertilizer N retention were increased by 20% and 10.47% to 94.52%, respectively, indicating that biochar was more capable for fertilizer N retention than promote plant adsorption. Moreover, inorganic N content in biochar treatment was greatly increased, which implies the increased N mineralization. In total, we concluded that biochar application was a potential urea enhancer during plant production.

Combined Use of Biochar with 15Nitrogen Labelled Urea Increases Rice Yield, N Use Efficiency and Fertilizer N Recovery under Water-Saving Irrigation

“…A similar positive impact of biochar on N recovery result of also observed from a previous study [76]. Liu et al [77] demonstrated that the inclusion of biochar with urea accelerated fertilizer N retention and increased N mineralization in the soil, which possibly resulted in enhanced N uptake with the improved FNR of rice.…”

Biochar‐based land development

“…For zucchini (corgette) crops, biochar increased N and P use efficiency has been noted on calcareous sandy soil (El-Eyuoon et al, 2017). In maize, it effectively improved the N use efficiency and yield on poor sandy soil (Omara et al, 2020) and reduced N loss from loamy soil (Liu, Cheng et al, 2017;Liu, He et al, 2017).…”

“…Meena et al (2020) have reported enhanced soil organic carbon, ammonium-N, and nitrate-N concentration in soil with the mixed application of biochar and N fertilizer than without biochar. However, a 4-year pot experiment by (Liu, Cheng et al, 2017;Liu, He et al, 2017) claimed an increase in retention of urea in soil but without acquisition by the plant when maize stover biochar was added. Furthermore, Melaku et al (2020) observed a lower marginal agronomic efficiency with biochar amendment than sole N predicting that plants utilized applied nutrients more efficiently without biochar at low doses of chemical fertilizers.…”