Biochar addition and reduced irrigation modulates leaf morpho-physiology and biological nitrogen fixation in faba bean-ryegrass intercropping

Xuezhi Liu; Weilun Liu; Zhenjuan Su; Junsheng Lu; Peng Zhang; Mengting Cai; Wangcheng Li; Fulai Liu; Mathias Neumann Andersen; Kiril Manevski

doi:10.1016/j.scitotenv.2024.171731

Biochar addition and reduced irrigation modulates leaf morpho-physiology and biological nitrogen fixation in faba bean-ryegrass intercropping

Sci Total Environ. 2024 May 15:925:171731. doi: 10.1016/j.scitotenv.2024.171731. Epub 2024 Mar 15.

Authors

Affiliations

¹ School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, China; Engineering Technology Research Center of Water-Saving and Water Resource Regulation in Ningxia, Yinchuan 750021, China; Ningxia Waler-saving Irrigation and Water Resource Control Engineering Technology Research Center, Yinchuan, Ningxia 750021, China. Electronic address: liu0816xuezhi@163.com.
² School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, China.
³ School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, China. Electronic address: szj1644yyds@126.com.
⁴ State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, China.
⁵ School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, China; Engineering Technology Research Center of Water-Saving and Water Resource Regulation in Ningxia, Yinchuan 750021, China; Ningxia Waler-saving Irrigation and Water Resource Control Engineering Technology Research Center, Yinchuan, Ningxia 750021, China.
⁶ Department of Plant and Environmental Science, Faculty of Science, University of Copenhagen, Højbakkegaard Alle 13, 2630 Taastrup, Denmark; Sino-Danish Center for Education and Research, Eastern Yanqihu campus, University of Chinese Academy of Sciences, 380 Huaibeizhuang, 101400 Beijing, China.
⁷ Department of Agroecology, Aarhus University, Blichers Allé 20, 8830 Tjele, Denmark; Sino-Danish Center for Education and Research, Eastern Yanqihu campus, University of Chinese Academy of Sciences, 380 Huaibeizhuang, 101400 Beijing, China.
⁸ Department of Agroecology, Aarhus University, Blichers Allé 20, 8830 Tjele, Denmark; Sino-Danish Center for Education and Research, Eastern Yanqihu campus, University of Chinese Academy of Sciences, 380 Huaibeizhuang, 101400 Beijing, China. Electronic address: kiril.manevski@agro.au.dk.

PMID: 38492602
DOI: 10.1016/j.scitotenv.2024.171731

Abstract

Intercropping legume with grass has potential to increase biomass and protein yield via biological N₂-fixation (BNF) benefits, whereas the joint effects of biochar (BC) coupled with deficit irrigation on intercropping systems remain elusive. A ¹⁵N isotope-labelled experiment was implemented to investigate morpho-physiological responses of faba bean-ryegrass intercrops on low- (550 °C, LTBC) or high-temperature BC (800 °C, HTBC) amended sandy-loam soil under full (FI), deficit (DI) and partial root-zone drying irrigation (PRD). LTBC and HTBC significantly reduced intrinsic water-use efficiency (WUE) by 12 and 14 %, and instantaneous WUE by 8 and 16 %, respectively, in faba bean leaves, despite improved photosynthetic (A_n) and transpiration rate (T_r), and stomatal conductance (g_s). Compared to FI, DI and PRD lowered faba bean A_n, g_s and T_r, but enhanced leaf-scale and time-integrated WUE as proxied by the diminished shoots Δ¹³C. PRD enhanced WUE as lower g_s, T_r and guard cell length than DI-plants. Despite higher carbon ([C]) and N concentration ([N]) in faba bean shoots amended by BC, the aboveground C- and N-pool of faba bean were reduced, while these pools increased for ryegrass. The N-use efficiency (NUE) in faba bean shoots was reduced by 9 and 14 % for LTBC and HTBC, respectively, but not for ryegrass. Interestingly, ryegrass shoots had 52 % higher NUE than faba bean shoots. The N derived from atmosphere (% Ndfa) was increased by 2 and 9 % under LTBC and HTBC, respectively, while it decreased slightly by reduced irrigation. Quantity of BNF in faba bean aboveground biomass decreased with HTBC coupled with reduced irrigation, mainly towards decreased biomass and soil N uptake by faba bean. Therefore, HTBC might not be a feasible option to improve WUE and BNF in faba bean-ryegrass intercropping, but PRD is permissible as the clear trade-off between BC and PRD.

Keywords: Biological nitrogen fixation; High-temperature pyrolysis biochar; Partial root-zone drying irrigation; Stomatal anatomy; Water-use efficiency.

MeSH terms

Charcoal*
Lolium*
Nitrogen Fixation
Plant Leaves / physiology
Soil
Vicia faba*

Substances

biochar
Soil
Charcoal