||Soil-Plant-Water Environment Research.
Horto, Maurice L. ;
Carlso, Charles G. ;
Ston, Loyd R. ;
||South Dakota State Univ., Brookings. Water Resources Research Inst.
||DI-14-01-0001-1862; OWRR-A-018-SDAK; 06518,; A-018-SDAK(2)
( Soil moisture ;
( Grain sorghum plants ;
Water loss ;
Temperature measurement ;
South Dakota ;
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A number of field observations were made within an actively growing crop environment. The observations included soil water movement, evapotranspiration rates, plant canopy temperatures, and water use predictions based on plant and meteorological conditions. The results show that within three days following irrigation of a Great Bend silt loam soil water movement was upward at the 15-20 cm depth. Nineteen days following irrigation water movement was upward at the 130-150 cm depth. Evapotranspiration rates for grain sorghum determined by tensiometric methods during a 31-day study period averaged 0.35 cm per day. During the 31-day study, approximately 65% of the total water loss from the soil profile was due to evapotranspiration and approximately 35% was due to flux below the root zone. Grain sorghum canopy temperatures were observed to reflect soil water conditions and changes in meteorological conditions. Irrigated sorghum canopy temperatures were usually 1-2 C cooler than nonirrigated sorghum canopy temperatures with maximum differences up to 5 C observed. Canopy temperatures changed almost immediately in response to a change in meteorological conditions.