Physiological and microclimatic consequences of variation in agricultural management of maize

Background: Maize is cultivated under different agricultural management systems, which influence the ecological dynamics of the crop, and therefore the physiology of the plant. Questions: What is the effect of different agricultural management on the microclimate and the physiology of maize plants? Studied species: Zea mays L. Study site and dates: Nacajuca, Tabasco, Mexico; January to April 2017. Methods: Physiological performance of maize plants and microclimatic variation in the crop area was characterized under three management systems: maize monoculture, maize-bean, and maize-bean-squash intercropping. Each treatment was established in three 100 m2 plots (300 m2 per treatment). Four measurements were taken between days 33 and 99 after maize sowing, to characterize five microclimatic parameters (relative air humidity, air and soil temperature, vapor-pressure deficit and soil volumetric water content) and nine physiological parameters (photosynthesis, transpiration, water use efficiency, stomatal conductance, electron transport rate, quantum efficiency of photosystem II, non-photochemical quenching, foliar water potential and chlorophyll content). Results: Maximum soil temperature was up to 4.4 ºC less in the maize-bean system than in the monoculture at 15:00 h; soil in the maize-bean-squash intercropping retained up to 45 % more water than the monoculture throughout the day. Photosynthesis and electron transport rate in the maize-bean intercropping was up to 32 % higher than in the monoculture. The highest non-photochemical quenching and transpiration rate were observed in the maize-bean-squash system. Conclusions: The maize-bean and maize-bean-squash combination provides maize plants with lower soil temperature and higher water availability, allowing them better physiological performance compared to monoculture.