Comparing the Effectiveness of Selected Cover Crops Incorporated as Green Manures without and with a Surface Seal Against Root Pathogens of Beans/Vegetables 2001
Type of grant: Cultural Methods / Biological Control
Project location(s): Findings are applicable nationally
Abstract: Green manures of a number of rotational and cover crops have been shown to effectively suppress the severity of root diseases and improve crop yield. We have recently documented that sudangrass incorporated as a green manure is effective in suppressing the root-knot nematode on vegetable crops. The principal mechanism involved in the observed suppression was shown to be due to the production of gaseous toxic compounds during the decomposition of the green manures in soil. This project was conducted to evaluate the effectiveness of green manures of sudangrass and wheat in suppressing root rot diseases of beans, thus the development an environmentally compatible management strategy for this important disease. Bean and fallow treatments were also included as checks. The replicated trial was established in a 2-acre experimental field, which is heavily infested with root rot pathogens. Sudangrass and wheat were planted on 5 June and incorporated on 9 August at rates of 29.4 and 5.3 T/A, respectively. Half of each of the plot areas were also sealed with a cultipacker-roller. The main results of this project will not be available until the end of the 2002 growing season. However, results of a greenhouse bioassay test showed that beans grown in soils collected from the sealed plots and receiving the green manure of sudangrass exhibited a slightly lower root rot severity. It is hoped that the suppression of root diseases will increase substantially prior to the next planting season.