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Intercropping legume with grass has potential to increase biomass and protein yield via biological N 2 -fixation (BNF) benefits, whereas the joint effects of biochar (BC) coupled with deficit irrigation on intercropping systems remain elusive. A 15 N 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 Δ 13 C. 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., Competing Interests: Declaration of competing interest The authors declare no competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Quantitative knowledge of the spatial variability of soil infiltration processes caused by canopy rainfall redistribution has significant hydro-chemical consequences owing to their influence on nutrients leaching and groundwater recharge in agricultural ecosystems. The heterogeneity of throughfall and stemflow under the maize canopy was quantified in this study, and its subsequent effect on soil water distribution at the row scale was further examined. Throughfall at 15 locations within and between maize rows as well as stemflow was observed over three growing seasons of 2015, 2016 and 2017 on the Loess Plateau of China. Soil water content at five depths in the row and interrow positions were continuously monitored. The results showed that throughfall was significantly different among the five sampling sections between maize rows, with the highest throughfall in the center and a decreasing trend towards the maize row. Greater throughfall was observed on the windward side of the maize row than on the leeward side. These spatial patterns persisted for most rainfall events. However, much higher net rainfall (throughfall plus stemflow) was obtained in the row positions when stemflow was further considered. Net rainfall reaching the row positions resulted not only in earlier water infiltration, but also in deeper penetration. The results suggested that the presence of maize canopy altered the soil surface water flux and thus caused heterogeneous infiltration water in the soil, which has implications for guiding the placing of fertilizers/pesticides and soil erosion management in the maize field., (Copyright © 2019 Elsevier B.V. All rights reserved.)