Eco-physiological processes underlying maize water use efficiency response to plant density under contrasting water regimes

HERNÁNDEZ, M.D.; ALFONSO, C.; CERRUDO, A.; CAMBARERI, M.; DELLA MAGGIORA, A.; BARBIERI, P.; ECHARTE, M.M.; ECHARTE, L.

FIELD CROPS RESEARCH

ELSEVIER SCIENCE BV

Año: 2020 vol. 254

0378-4290

This study quantified maize (Zea maysL.)water use efficiency for grain yield (WUEg) in response to plantdensity under contrasting water regimes; and focused on relevant eco-physiologial processes underlying theresponses of maize WUEg to plant density (i.e., the proportion of transpiration in the total water used, T/ET; andthe crop growth rate during the critical period for kernel set, CGRcp). Maize crops were grown at Balcarce,Argentina during two seasons. Treatments included two water regimes (i.e., rainfed and irrigated) and threeplant densities (4, 8 and 12 plants m−2). Measurements comprised (i) soil water content and iPAR during thewhole growing season, (ii) shoot biomass around silking and (iii) grain yield and shoot biomass at physiologicalmaturity. Crop ET was calculated by means of water balance and soil evaporation was measured with micro-lysimeters. The response of WUEg to increasing plant density from 4 to 8 or from 4 to 12 plants m−2wasinfluenced by seasonal water supply. Both seasonal ET and T/ET consistently increased with plant densitiesacross contrasting water regimes. Although increments in T/ET partition were in accordance with increasingiPAR, they did not promote higher WUEg at low water supply. Grain yield increased with plant density, except inthe driest environment where no response of either grain yield nor WUEg to plant density was detected. Ourresults showed that the response of CGRcp to plant density increments (i) depended on the water supply, and (ii)contributed to explain WUEg response to plant density under contrasting water supplies