Response of water related grain yield determinants to management practices

ECHARTE, L.; ALFONSO, C.; HERNANDEZ, M.; ECHARTE, M.M.

Dakar

Congreso; Interdrought 2022; 2022

CIRAD, IRD, ISRA

Response of water-related grain yield determinants to management practicesLaura Echarte, Carla Alfonso, Mariano Hernández, Mercedes Echarte RATIONALEGrain yield is closely related to water resources and results from the combination of seasonal evapotranspiration (ET) and water use efficiency for grain production (WUEG,ET,s). This work studies the influence of N supply, plant density or soil cover on crop ET, WUEG,ET,s and their determinants (light interception, proportion of transpired water (T/ET), biomass produced per unit of transpired water (B/T) and reproductive growth) in main crops grown in Argentina. METHODSThe study compiles field experiments including different management practices (N supply, plant density or soil cover) and crops (maize, sunflower or soybean) under water limited and non-water limited conditions. Soil water balances were used to estimate crop ET and evaporation (E). Transpiration (T) was estimated as ET–E. RESULTSManagement practices that increased crop’s light interception (high plant density and N supply), increased crop ET by increasing T, with a stronger effect in non-water limited conditions. Soil cover reduced crop ET, with higher effect at larger cover crop biomass. Increasing plant density and N supply, increased WUEG,ET,s in non-water limited conditions, but not in rainfed conditions. In non-water limited environments, increments in WUEG,ET,s were attributed to higher T/ET, B/T and reproductive growth. Under rainfed conditions, reproductive growth limited WUEG,ET,s response to management practices. CONCLUSIONS & PERSPECTIVESThe effects of management practices that stabilize or increase grain yield through changes in ET, WUEG,ET,s and their determinants, are mediated by their influence on light interception and depend on water availability for crop growth.