Effects of Fresh and Decomposing Corn Plant Residue Extracts on Corn Seedling Development
1984
Yakle, G. A. | Cruse, R. M.
Early corn (Zea mays L.) growth is frequently reduced in tillage systems that leave large amounts of corn residue on or near the soil surface. This effect may be due, in part, to the release of phytotoxic chemicals from the residue during rainfall or microbial breakdown. Laboratory experiments were conducted to investigate the activity of corn residue phytotoxins after movement through soil by using a corn seed bioassay for measurement. Corn seeds were germinated in tap water solutions extracted from corn residues that had been incubated with or without soil for 0, 15, or 30 d under wet, poorly aerated conditions. The extracted corn residue solutions were then either filtered or not filtered through columns of sterilize soil before being used to germinate the seeds. The corn seedlings were grown without light for 7 d in a growth chamber maintained at 22°C. A tap water check treatment was included in the study. Extracts of corn residue incubated without soil resulted in 39% as much root growth as did the check treatment. Incubation of the residue with soil reduced the inhibitory effects of the extracts, as did filtration of the corn residue extracts through the sterilized soil columns. The results suggest that phytotoxins extracted from corn residues incubated with soil were inactivated in the soil by microbial breakdown. Phytotoxins, however, were able to move through the sterilized soil columns without significant alteration of their inhibitory properties.
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