Project at a Glance
Title: Effects of SO2 on growth and yield of winter crops grown in California.
Principal Investigator / Author(s): Thompson, C. Ray
Contractor: Statewide Air Pollution Research Center, UC Riverside
Contract Number: A3-057-33
Research Program Area: Ecosystem & Multimedia Effects
Topic Areas: Agriculture, Ecosystem Impacts
The sulfur dioxide sensitivity of California crop plants grown during the winter was tested using lettuce (Lactuca sativa cv Empire) and wheat (Triticum aestivum cv Yecoro Rojo). The plants were grown in soil inside open top field chambers for 79 (lettuce) and 150 (wheat) days. Treatments include nonfiltered ambient air without added sulfur dioxide; filtered ambient air with 0, 79, 183 and 393 µg/m3 added sulfur dioxide; and out- side plots. Two harvests were made for each species: after 14 and 47 days of exposure for lettuce and after 47 and 118 days for wheat. The results clearly indicated that winter exposures to sulfur dioxide can injure California crops. For wheat, sulfur dioxide at 183 µg/m3 decreased wheat height by 5% and leaf area by 14% at the first harvest. Sulfur dioxide significantly reduced wheat yields at the final harvest. Sulfur dioxide at 393 µg/m3 reduced total seed weight by 26%; and at 79 µg/m3 and above, reduced 100 seed weight by 8% or more. Sulfur dioxide had no overall effect on lettuce plants at either harvest. Ambient oxidants had no overall effect on growth of lettuce or wheat. All chamber grown plants in general showed greater growth and yield than outside plants, indicating that the air pollutant sensitivity may be different for chamber-grown versus field-grown plants.
For questions regarding this research project, including available data and progress status, contact: Heather Choi at (916) 322-3893
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