Site-specific analysis of a droughted corn crop: II. Water use and stress.

摘要: In the southeastern USA Coastal Plain, spatial variation in soils causes extreme grain yield, as seen yield maps. Corn (Zea mays L.) appears to be particularly susceptible soil variation, espedally during periods of drought. Our objectives were compare water use and stress corn within among map units. one field, at two sites each four units, we measured site-specific effects on crop from 40 d after planting until maturity using a time-domain reflectometer (TDR). On 4 vegetative growth, drought was evaluated eight transects infrared thermometer (IRT) measurements canopy temperature (T c ). During most severe drought, visibly stressed areas had canopy-air differences - T,) > 10°C, yet other remained <2°C. Two days 46-mm rain, T T, near zero over whole indicating little stress. The time series TDR produced estimates daily evapotranspiration, runoff, infiltration; site-to-site these dominated balance. Water stress, inferred use, matched that earlier components. sum, arrived final via fundamentally different paths. Further, between significant, soll units are not homogenous with respect relations. These results underscore need for within-season observations augment interpretation yleid