Effects of Chronic Doses of Ozone and Sulfur Dioxide on Injury and Yield of Soybeans in Open‐Top Field Chambers¹

Abstract

Soybeans, Glycine max (L.) Merr. ‘Davis’, were exposed for 7 h day−1 (111 days) to six concentrations of ozone (O3) and for 4 h day−1 (101 days) to four concentrations of sulfur dioxide (SO2), singly and in mixtures (24 combinations). The pollutant concentrations were selected to span those that occur in major soybean production areas of the USA. The pollutant dose‐yield response relationships were modeled using regression analyses and a Weibull model analysis. Both analyses indicated that a dose of O3 typical for soybean production areas (seasonal 7—h day−1 mean of 0.055 ppm v/v) caused a seed weight decrease of 20% compared to a control dose of 0.025 ppm O3. Sulfur dioxide at levels known to exist regionally in the USA (seasonal 4—h day−1 mean of <0.026 ppm SO2) did not cause injury or affect soybean yield. Neither pollutant changed the dose‐response relationships for the other except at high concentrations where the effect of mixtures was less than the additive effects of the pollutants singly. The dose‐response relationships were similar for each of two soil types.

Ozone and Crop Yield*

“…At Argonne, IL; the range of responses for two winter wheat cultivars was from 9% greater to 7% less in the NF than in the CF chambers (64). The yield of Davis soybean over four seasons at Raleigh, NC, ranged from 8% less to 14% greater in the NF than in the CF treatment (21,25,27). On the other hand, the response of Williams soybean at Beltsville, MD was fairly uniform over two seasons, showing a mean loss of 10% in NF chambers ( Table 2) (48).…”

“…(33,36). The 03 dose-yield response relationships for soybean grown in a sandy-loa m soil or in a clay-loam soil were not significantly different (25).…”

Yield Response of Davis Soybeans to Simulated Acid Rain and Gaseous Pollutants in the Field

“…Ozone concentrations in 1984 were sufficiently high to elicit yield reduction between 12 and 18%, based on the response functions for yield developed for Davis soybeans by Heck et al (1983). The data from which these response functions were derived came from an experiment (Heagle et al, 1983a) in which irrigation was used to double the amount of water that soybeans would receive in an average year for rain (32 cm of rain, 30 or 34 cm of irrigation water) in North Carolina where the experiment was performed. The effects of a doubling of the water supply on the sensitivity of soybeans to O3 are, at present, not known.…”

“…The yield response of soybeans to O3 in the field in NCLAN experiments was predominantly a linear yield decrease with increasing seasonal 7 h d^^ concentrations (Heagle et al, 1983a;Heck et al, 1983;Kress & Miller, 1983). When data were fitted to WeibuU models, estimated yield losses for soybeans from 7-h daily mean O3 concentrations representative of current ambient levels of O3 pollution ranged from 7-9 to 18-6% (Heck et al, 1983).…”

Considerations for Evaluating Controlled Exposure Studies of Tree Seedlings

“…Building on exposure studies of crops in the National Crop Loss Assessment Network (e.g., see Heagle et al, 1983;, the experimental designs were generally a variation of split plot or randomized blocks, with chambers rather than seedlings as the units of replication because chambers are the level at which the pollutant treatment can be applied.…”