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Response of ‘Norman’ soybeans [Glycine max(L.) Merr.] to a shelter‐induced microclimate was studied under dryland and irrigated soil water regimes. Leaf water potential (Ψ1), xylem water potential (ΨX), stomatal diffusion resistance (rB), canopy temperature, dry matter accumulation, leaf area, leaf density, plant height, and yield components were measured to determine the effects of shelter influences on a soybean crop. Plant water status, characterized by measuring Ψ1, ΨX, rB, and canopy temperature during selected days, was strongly affected by soil water regime and sheltered conditions. The treatment combination of shelter plus irrigation resulted in the most favorable plant water status. Under dryland, where soil water was limiting, plant water status of the sheltered and exposed treatments was similar. Dry matter production, green leaf area, and plant height were generally increased under sheltered treatments if soil water was not limiting. Dryland sheltered treatments showed early vegetative stimulation when compared to exposed treatments, but the resulting depletion of soil water in the sheltered treatment restricted later growth. Both irrigated and dryland sheltered plants had a lower leaf density compared to exposed plants. Soybean yields were increased from 20.4 hl/ha for the irrigated exposed treatment to 24.0 hl/ha for the irrigated sheltered treatment. Under dryland, the yields were 11.8 and 12.8 hl/ha for exposed and sheltered treatments, respectively.

The Penman formula in three modifications accounts reasonably well for the observed values. Roughly, evapotranspiration was equivalent to 0.8 of net radiation over the crop.

The roots of tobacco plants were subjected to a wide range of simulated aeration conditions. In general plant functions were not appreciably reduced until the CO2concentration became greater than the O2concentration but were sharply reduced after the CO2to O2ratio became larger than one.

The roots of tobacco plants were subjected to a wide range of simulated aeration conditions. In general nutrient uptake remained relatively constant until oxygen concentrations dropped below 10%. However, a concentration of 5% carbon dioxide apparently stimulated phosphorus uptake.