Growing Corn in Clumps Reduces Canopy Temperature and Improves Microclimate.

Uniform or evenly spaced planting (ESP) geometry is practiced when resources, such as water, are nonlimiting for growing crops, but under resource-limited environments, nonuniform treatment of the land can be an advantage. Corn (Zea maysL.) field studies were conducted in Gruver (Gruver field study, GFS) and Bushland (Bushland field study, BFS), Texas to compare plant canopy temperature, within-canopy vapor pressure deficit (VPD), grain yield, and yield components for clump (3 plants clustered) and ESP geometries with the same plant populations. At different growth stages for both studies, thermal images were taken for calculating canopy temperature (CT), and temperature and relative humidity (RH) within the plant canopy were measured. Overall, CTs were significantly lower for clumps compared with ESPs, and mean VPDs within the clumps were consistently lower than those for ESPs, indicating that clumps improved the microclimate. Compared with ESPs, clumps produced similar or higher grain yields, and harvest index (HI) was significantly higher for clumps than that for ESPs in both studies (0.56 vs. 0.54 in GFS and 0.48 vs. 0.45 in BFS). In GFS, plants were grown under three water levels (high, medium, and low). With decreasing irrigation level, canopy temperature and VPD increased and aboveground biomass, grain yield, and HI decreased. Results suggested that growing corn in clumps might be a useful strategy under semi-arid climatic conditions because they reduced CT, improved microclimate, decreased number of tillers, and increased HI with comparable grain yield compared with conventional ESPs. [ABSTRACT FROM PUBLISHER]