Preliminary Study on Germinable Summer Weed Seed Bank at Giza Farm Research Station, Agricultural Research Center, Egypt

Abstract

Despite efforts to eliminate weeds, they continue to thrive. Weed persistence is reliant upon the soil seedbank. Knowledge of the soil seedbank is continually expanding, but with the rising threat of herbicide-resistant weeds in agriculture, weed scientists have, in the past, focused their management tactics to more short-term solutions that tackle the aboveground problems, rather than long-term solutions. Uptill now, there are few studies about weed seed bank in Egypt. For this reason establishing weed seed bank studies about vertical and horizontal distribution patterns is needed for weed management in Egypt. The present study was carried out during 2018 and 2019 summer seasons to evaluate the magnitude of the non-dormant weed seed bank of summer annual weeds in five different basins in Giza research station. Weed seed germination was kept under observation for a period of six weeks and the germinated seeds were counted weekly and removed after that. The results indicated that most of weed seeds were concentrated in the above 0-5 cm layer followed by 5-10 cm layer and the least were found in 10-15cm layer from soil surface. Most of weed seeds germinated in 1 st and 2 nd weeks, and decreased gradually in the next weeks, where about 95% of weed seeds in soil profile were germinated in the first five weeks. The existed weed flora contained 15 species which differ in their richness from one basin to another. The highest number of germinated weed seeds were recorded in basin 12 (498.8 and 408.1 seedling/kg of soil) in 1 st and 2 nd seasons, respectively, while the least number of germinated weed seeds were found in basins 19 (45.7 and 64.0 seedlings/kg of soil) in 1 st and 2 nd seasons, respectively. By using ANOVA statistical analysis, experimental error decreased by taking 3-4 soil samples, to give adequate accuracy for soil seed bank determination than taking one soil sample. The relationship between number ofseedlings/m 2 and CV% was linear equations: "CV%= -0.26 × Number of seedlings + 29.53" and "CV%= -0.4 × Number of seedlings + 31.103" in the first and second summer seasons, respectively. In conclusion weed seed bank determination in soil is a key for sustainable agriculture in Egypt. The present study throws light of vertical or horizontal distributions in soil profile in seed bank as a good tool for improving weed management in cropping system in Egypt.