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Comparison of pots versus microcosms for predicting agroecosystem effects due to waste amendment
Author(s) -
Tolle Duane A.,
Arthur Mickey F.,
Chesson Jean,
Van Voris Peter
Publication year - 1985
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620040410
Subject(s) - microcosm , amendment , agronomy , medicago sativa , yield (engineering) , crop , avena , agroecosystem , field experiment , chemistry , zoology , mathematics , horticulture , environmental science , biology , ecology , environmental chemistry , agriculture , materials science , political science , law , metallurgy
Two laboratory test units (plastic flower pots and intact soil‐core microcosms) were compared for their accuracy in predicting crop yield and element uptake in field plots. All three test units were amended with four treatment levels of unweathered, acidic fly ash (0, 100, 400 and 700 t/ha), fertilized with alfalfa meal and planted in late June with equivalent rates of Saranac alfalfa (Medicago sativa) , Climax timothy (Phleum praetense) and Clintford oats (Avena sativa). Microcosms were more accurate than pots in predicting the dose‐response yield curve for alfalfa/timothy grown in field plots. The hypothesis of parallelism between regression equations for alfalfa yield was rejected for pots versus field plots, but was not rejected for microcosms versus field plots. Neither of the two laboratory units accurately predicted the dose‐response curves for oat grain or total oat yield. Pots were only slightly more accurate than microcosms in predicting the enrichment ratios (ERs) for alfalfa uptake of elements from field plots, based on statistical analysis of the distributions of In‐ER ratios for 22 elements. The extra rooting depth of the 60‐cm microcosms may provide more accurate yield data for long tap‐rooted species like alfalfa, as well as permit a second year of accurate data on crop yield and element uptake.